This notice of written consent and appraisal rights and information statement is being furnished to the holders of common stock, par value $0.001 per share (the “Company Common Stock”), of Integral Ad Science Holding Corp., a Delaware corporation (“IAS”), in connection with the Agreement and Plan of Merger, dated as of September 24, 2025 (the “Merger Agreement”), by and among IAS, Igloo Group Parent, Inc., a Delaware corporation (“Parent”), and Igloo Group Acquisition Company, Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“Merger Sub”). Parent and Merger Sub are affiliates of investment funds managed by Novacap Management Inc. A summary of the Merger Agreement is provided in the accompanying information statement and a copy of the Merger Agreement is attached as Annex A to the accompanying information statement, and each are incorporated by reference into this notice. Pursuant to the Merger Agreement, Merger Sub will be merged with and into IAS (the “Merger”), with IAS surviving the Merger as a wholly owned subsidiary of Parent. Upon consummation of the Merger, on the terms and subject to the conditions set forth in the Merger Agreement, each share of Company Common Stock issued and outstanding as of immediately prior to the effective time of the Merger (the “Effective Time”) will be automatically cancelled, extinguished and converted into the right to receive cash in an amount equal to $10.30, without interest thereon (the “Per Share Price”). However, the Per Share Price will not be paid in respect of (i) any shares of Company Common Stock held by IAS as treasury stock or held by any subsidiary of IAS or owned by Parent or any of its subsidiaries (including Merger Sub), in each case as of immediately prior to the Effective Time, which shares will automatically be cancelled and extinguished without any conversion thereof or consideration paid therefor, and (ii) those shares of Company Common Stock held by any person who has properly exercised appraisal rights of such shares of Company Common Stock under Delaware law and has not withdrawn his, her or its demand for appraisal or has not lost or waived such rights.

The board of directors of IAS has unanimously (i) determined that it is fair to and in the best interests of IAS and its stockholders, and declared it advisable, to enter into the Merger Agreement providing for the Merger, in accordance with the General Corporation Law of the State of Delaware (the “DGCL”); (ii) approved and declared advisable the Merger Agreement, the execution and delivery of the Merger Agreement by IAS, the performance by IAS of its covenants and other obligations thereunder, and the consummation of the Merger upon the terms and conditions set forth therein; (iii) resolved to recommend that IAS’s stockholders adopt the Merger Agreement and the Merger in accordance with the DGCL; and (iv) directed that the Merger Agreement be submitted to IAS’s stockholders for adoption.

The adoption of the Merger Agreement by IAS’s stockholders required the affirmative vote or written consent by holders of a majority of the voting power of the outstanding shares of Company Common Stock entitled to vote thereon.

On September 24, 2025, following the execution of the Merger Agreement, Vista Equity Partners Fund VI, L.P., Vista Equity Partners Fund VI-A, L.P., VEPF VI FAF, L.P. and Atlas Venture Fund VIII, L.P. (collectively, the “Consenting Stockholders”), which on September 24, 2025 held of record and beneficially owned 87,732,772 shares of Company Common Stock representing approximately 52.6% of the aggregate voting power of the then issued and outstanding shares of Company Common Stock, delivered a written consent approving and adopting in all respects the Merger Agreement and the transactions contemplated by the Merger Agreement,

including the Merger (the “Written Consent”). As a result, no further action by any stockholder of IAS is required under applicable law or the Merger Agreement (or otherwise) to adopt the Merger Agreement, and IAS will not be soliciting your vote for or consent to the adoption of the Merger Agreement and the approval of the transactions contemplated by the Merger Agreement and will not call a stockholders’ meeting for purposes of voting on the adoption of the Merger Agreement and the approval of the transactions contemplated by the Merger Agreement. Under Section 228(e) of the DGCL, where stockholder action is taken without a meeting and by less than unanimous written consent, prompt notice of the taking of such corporate action must be given to those stockholders who have not consented in writing and who, if the action had been taken at a meeting, would have been entitled to notice of the meeting if the record date for such meeting had been the date that written consents signed by a sufficient number of holders to take the action were delivered to the corporation as provided in subsection (c) of Section 228 of the DGCL. This notice and the accompanying information statement are being mailed to persons who were holders of record of the shares of Company Common Stock as of the close of business on the date the Written Consent was delivered and shall constitute notice to you from IAS of the Written Consent, as contemplated by Section 228(e) of the DGCL.

Under Section 262 of the DGCL, if the Merger is completed, subject to compliance with the requirements of Section 262 of the DGCL, holders of shares of Company Common Stock, other than the Consenting Stockholders, will have the right to seek an appraisal for, and be paid the “fair value” in cash of, their shares of Company Common Stock (as determined by the Delaware Court of Chancery), together with interest, if any, on the amount determined to be fair value, instead of receiving the Per Share Price pursuant to the Merger Agreement. To exercise your appraisal rights, you must submit a written demand for an appraisal to IAS no later than 20 days after the mailing of this information statement, which mailing date is November 7, 2025, and comply precisely with all of the procedures set forth in Section 262 of the DGCL, which are summarized in the accompanying information statement. A copy of Section 262, which details the applicable Delaware appraisal statute, may be accessed without subscription or cost at the following publicly available website: https://delcode.delaware.gov/title8/c001/sc09/index.html#262. This notice and the accompanying information statement shall constitute notice to you from IAS of the availability of appraisal rights under Section 262 of the DGCL in connection with the Merger.

We urge you to read the entire information statement carefully. If the Merger is completed, you will receive instructions regarding payment for your shares of Company Common Stock.

The following questions and answers are intended to briefly address commonly asked questions as they pertain to the Merger Agreement and the Merger. These questions and answers may not address all questions that may be important to you as an IAS stockholder. Please refer to the “Summary” beginning on page 1 and the more detailed information contained elsewhere in this information statement, the annexes to this information statement and the documents referred to or incorporated by reference in this information statement, each of which you should read carefully. You may obtain additional information, which is incorporated by reference in this information statement, without charge by following the instructions in the section entitled “Where You Can Find More Information” beginning on page 85.

This information statement, and the documents to which we refer you in this information statement, contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), including, without limitation, statements regarding forecasts and projections as described in “The Merger—Certain Company Financial Forecasts” beginning on page 42, which are subject to the “safe harbor” created by those sections. Forward-looking statements are based on our management’s beliefs and assumptions and on information currently available to our management. All statements other than statements of historical fact, including statements regarding our current expectations relating to the Merger and the transactions contemplated by the Merger Agreement, our future results of operations and financial position, our business strategy and plans, our objectives for future operations, and any statements of a general economic or industry specific nature, are forward-looking statements. You can identify forward-looking statements by the fact that they do not relate strictly to historical or current facts. Words such as “approximately,” “anticipate,” “estimate,” “expect,” “future,” “project,” “plan,” “intend,” “assume,” “contemplate,” “believe,” “may,” “will,” “should,” “continue,” “could,” “can have,” “likely,” “outlook,” “potential,” “targets,” “seek,” “will,” “contemplates,” or the negative or plural of these words and similar expressions are intended to identify forward-looking statements. We have based these forward-looking statements largely on our current expectations and projections about future events and trends that we believe, based on information currently available to our management, may affect our financial condition, results of operations, business strategy, short-term and long-term business operations and objectives, and financial needs. These forward-looking statements are subject to a number of risks, uncertainties and assumptions, related to our operations, financial results, financial condition, business, prospects, growth strategy, and liquidity. Accordingly, there are, or will be, important factors that could cause our actual results to differ materially from those indicated in these statements. We believe that these factors include, but are not limited to:

Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the future events and trends discussed in this information statement may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur. Although we believe that the expectations and assumptions reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of activity, performance, or achievements. We undertake no obligation to publicly update any forward-looking statement after the date of this report, whether as a result of new information, future developments or otherwise, or to conform these statements to actual results or revised expectations, except as may be required by applicable law.

IAS is a leading global media measurement and optimization platform. Its mission is to be the global benchmark for trust and transparency in digital media quality for the world’s leading brands, publishers, and platforms. With our cloud-based technology platform and the actionable insights it provides, we deliver independent measurement and optimization of digital advertising to over 2,000 advertising customers across all devices, channels, and formats, including desktop, mobile, CTV, social, display, video and emerging media like audio and gaming. IAS’s Quality Impression® is a proprietary metric that helps ensure media quality standards. The viewability and invalid traffic filtration aspects of a Quality Impression are accredited by the MRC across desktop and mobile platforms. Without an independent evaluation of digital advertising quality, brands and their agencies previously relied on a wide range of publishers and ad platforms to self-report and measure the effectiveness of campaigns without a global benchmark or holistic reporting platform to understand success. IAS is an independent, trusted partner for buyers and sellers of digital advertising to increase accountability, transparency, and effectiveness in the market. IAS helps advertisers optimize their ad spend and better measure consumer engagement with campaigns across platforms, while enabling publishers to improve their inventory yield and revenue. IAS’s principal executive offices are located at 12 East 49th Street, 20th Floor, New York, NY 10017 and its telephone number is (646) 278-4871. IAS’s website is www.integralads.com. The information provided on or accessible through our website is not incorporated by reference into and is not part of this information statement. Additional information about IAS is included in documents incorporated by reference into this information statement and our filings with the SEC, copies of which may be obtained without charge by following the instructions in the section entitled “Where You Can Find More Information” beginning on page 85.

The Company Common Stock is listed with, and trades on, the Nasdaq under the symbol “IAS.”

Parent is a Delaware corporation that was formed solely for the purpose of entering into the Merger Agreement, consummating the Merger and engaging in the transactions contemplated by the Merger Agreement, and has not engaged in any business activities other than in connection with the transactions contemplated by the Merger Agreement and arranging of the equity financing and debt financing in connection with the Merger. Parent is an affiliate of investment funds managed by Novacap.

After the consummation of the Merger, IAS will be a wholly owned subsidiary of Parent. Parent’s principal executive offices are located at 3400, rue de l’Eclipse, Suite 700, Brossard, Québec, Canada, and its telephone number is +1 (450) 651-5000.

Merger Sub is a Delaware corporation that was formed by Parent solely for the purpose of entering into the Merger Agreement, consummating the Merger and engaging in the transactions contemplated by the Merger Agreement. Merger Sub is a wholly owned subsidiary of Parent and has not carried on any business activity other than in connection with the transactions contemplated by the Merger Agreement. Upon consummation of the Merger, Merger Sub will cease to exist. Merger Sub’s principal executive offices are located at 3400, rue de l’Eclipse, Suite 700, Brossard, Québec, Canada, and its telephone number is +1 (450) 651-5000.

The following chronology summarizes the key meetings and events that led to the signing of the Merger Agreement. The following chronology does not purport to catalogue every conversation among the Company Board, the Transaction Committee or the representatives of IAS and other parties.

As part of IAS’s ongoing consideration and evaluation of its long-term strategic goals and plans, the Company Board and IAS management periodically review, consider and assess the operations and financial performance of IAS, as well as overall industry conditions. These reviews include, among other matters, the consideration of potential opportunities for business combinations, acquisitions and other financial and strategic alternatives, including in response to indications of interest received from third parties, in each case, with a view towards enhancing stockholder value.

In the summer of 2024, the Company Board, based on the expertise and industry knowledge of each of Jefferies, Goldman Sachs (“Goldman”) and Morgan Stanley (“MS”), determined to invite representatives of each to present to the Company Board regarding its capabilities to assist the Company Board with evaluating and assessing potential strategic transactions available to IAS (including status quo trading, a potential sale or divestiture, and ECM-related products).

On July 23, 2024, the Company Board held separate meetings with representatives of Goldman and representatives of MS where each of Goldman and MS presented its views regarding the public market, IAS’s organic growth plan and potential strategic alternatives and impacts.

On August 8, 2024, the Company Board held a meeting with representatives of Jefferies where representatives of Jefferies similarly presented its views regarding the public market, IAS’s organic growth plan and potential strategic alternatives and impacts.

In August 2024, at the request of the Company Board, representatives of Jefferies reviewed with the Company Board a preliminary financial analysis of IAS based on Wall Street analyst estimates for IAS.

On September 22, 2024, the Company Board held a special meeting via videoconference with representatives of Jefferies and Kirkland & Ellis LLP (“Kirkland”), IAS’s regular outside legal advisor, in attendance, in order to discuss, among other topics, the strategic position of IAS and state of the advertising technology (“AdTech”) industry as well as the feasibility and advisability of a potential strategic review process with respect to a sale of IAS. Representatives of Jefferies and the Company Board discussed, among other things, challenges facing the AdTech industry generally and IAS specifically, including (among others) increased competition and macro-economic challenges that have resulted in reductions in customers’ brand marketing budgets, and also discussed IAS’s performance volatility and the receipt of unsolicited inbound interest from potential acquirors. At the request of the Company Board, representatives of Jefferies reviewed with the Company Board a preliminary list of financial sponsors and strategic companies that would potentially be interested in evaluating a transaction with IAS, and identified eight financial sponsors among that list as those most likely to be interested in a strategic transaction involving IAS and with the financial capacity and ability to complete such a transaction (collectively, those eight financial sponsors, the “Initial Outreach Sponsors”). The list of Initial Outreach Sponsors was compiled by representatives of Jefferies based on its expertise and industry knowledge, considering various factors that, among other things, reflected the parties’ knowledge of (and historical interest in) IAS and the broader industry sector in which it operates, their historical acquisition activity profile, their perceived approach to valuation, and risk tolerance and perceived equity capacity (including fund size). Following the presentation by representatives of Jefferies, representatives of Jefferies departed the meeting, at which time the Company Board discussed next steps, including whether to engage Jefferies as IAS’s financial advisor to conduct a broader review of potential strategic alternatives, and further considered the parties identified by representatives of Jefferies for potential outreach. Following discussion, the Company Board determined to engage Jefferies as IAS’s financial advisor in light of, among other things, Jefferies’ experience with transactions of this kind, historical knowledge of the AdTech industry generally and IAS specifically, its knowledge of certain potentially interested strategic and financial sponsor counterparties, and its views on a potential strategic review process as presented to the Company Board at the meeting, and to begin outreach as part of a strategic review process. The Company Board determined that representatives of Jefferies should begin reaching out to the Initial Outreach Sponsors and that representatives of Jefferies should also work to identify potential strategic companies for outreach. Also at this meeting, representatives of Kirkland reviewed with the

Company Board its fiduciary duties and certain process considerations in connection with the strategic review process and any potential resulting transactions. Representatives of Kirkland advised the Company Board that, if the Company Board determined to move forward with potentially interested counterparties, members of IAS’s management who became involved in the process should be instructed not to engage in discussions with any potential counterparty (or its representatives), with respect to employment, compensation or equity rollover matters unless authorized by the Company Board. Following the meeting, based on discussions with the Company Board, Mr. Rod Aliabadi, member of the Company Board, informed a representative of Jefferies that the Company Board determined to engage Jefferies, subject to entry into an acceptable engagement letter and conflicts disclosure, and instructed representatives of Jefferies to engage in preliminary discussions with the Initial Outreach Sponsors to determine their interest in a potential strategic transaction with IAS in connection with a broader review of potential strategic alternatives.

On September 29, 2024, the Company Board held a special meeting via videoconference, with members of IAS’s senior management, representatives of Jefferies and representatives of Kirkland present. During such meeting, among other topics, representatives of Jefferies provided an update with respect to the strategic review process, including that representatives of Jefferies had engaged in preliminary outreach to 26 potential counterparties, including 12 strategic companies who representatives of Jefferies and IAS had identified as potential strategic companies for outreach following the Company Board's instruction at the September 22, 2024 meeting, and 14 financial sponsors (the “2024 Outreach Parties”), 3 of whom had determined not to pursue an acquisition of IAS, citing that they had insufficient internal bandwidth to pursue, or lack of interest in pursuing, a potential transaction with IAS. Members of IAS management presented to the Company Board management’s long-range projections (the “September 2024 Forecasts” as discussed in further detail in the section of this information statement entitled “The Merger—Certain Company Financial Forecasts” beginning on page 42). The Company Board discussed the various assumptions contained in the September 2024 Forecasts and, following discussion, the Company Board authorized sharing of the September 2024 Forecasts with potential transaction counterparties in connection with the strategic review process whom had executed acceptable confidentiality agreements.

Over a period of several days starting on September 22, 2024, representatives of Jefferies, in accordance with the Company Board’s instructions at the September 22, 2024 meeting of the Company Board, commenced outreach to, and as applicable, negotiated confidentiality agreements through mid-October 2024 with, the 2024 Outreach Parties. 14 of these parties, consisting of 10 financial sponsors (“Party A,” “Party B,” “Party C,” “Party D,” “Party E,” “Party F,” “Party G,” “Party H,” “Party I” and “Party L,” respectively) and 4 strategic companies (“Party J,” “Party K,” “Party M” and “Party N,” respectively), executed separate confidentiality agreements with IAS. Each of the confidentiality agreements entered into by IAS with these potential counterparties included among other terms, a customary standstill provision that prohibited these parties (for an agreed upon period) from, among other things, offering to acquire IAS without the prior consent of the Company Board, except that certain of such potential counterparties could make confidential acquisition proposals directly to the Company Board at any time and the standstill would fall away after IAS entered into a definitive agreement with a third party providing for a change of control transaction of IAS. 12 of the 2024 Outreach Parties did not execute confidentiality agreements with IAS and did not attend a management presentation. Representatives of the parties that did not execute confidentiality agreements conveyed various reasons to representatives of Jefferies for determining not to pursue an acquisition of IAS, including, among other reasons, that a strategic transaction with IAS did not fit current strategic priorities, that IAS’s business was not a core priority for such party and concerns regarding pro forma revenue growth.

On October 5, 2024, prior to sharing any financial projections with potential bidders, IAS management sent an email update to the Company Board making some additional refinements to the September 2024 Forecasts, which refinements were made to (i) address an increase in the anticipated churn among key customers, (ii) incorporate revenue from certain new products offered by IAS and (iii) incorporate recently implemented price increases, all of which were immaterial (the “October 2024 Forecasts” as discussed in further detail in the section of this information statement entitled “The Merger—Certain Company Financial Forecasts” beginning on page 42).

On October 14, 2024, at the instruction of the Company Board following the September 22, 2024 meeting, representatives of Jefferies sent a process letter to the preliminary list of financial sponsors and strategic parties, requesting that these parties submit an indicative non-binding proposal by October 22, 2024. The process letter

requested, among other things, that each party provide their proposed purchase price, material assumptions underlying the purchase price, intended transaction structure, expected sources and uses of funding (including that potential counterparties who were willing to provide a full equity backstop would be viewed favorably in the process), due diligence timeline, post-transaction plans and a description of any internal review or approval processes.

Between October 7, 2024 and October 17, 2024, representatives of Party A, Party B, Party C, Party D, Party E, Party F, Party G, Party H, Party I, Party J, Party K, Party M and Party N each attended separate management presentations (“Management Presentations”) held by representatives of IAS.

On October 11, 2024, Party C verbally expressed to representatives of Jefferies that they were potentially interested in a transaction with IAS at a “market” premium to IAS’s then-current stock price, but given financing constraints, would need to partner with an equity co-investor to finance the transaction.

Between October 15, 2024 and October 21, 2024, representatives of Party A, Party B, Party C, Party F, Party G and Party L attended separate meetings held by members of IAS senior management and representatives of Jefferies to discuss, among other things, the projections model provided to such potential counterparties (each such discussion, a “Financial Discussion”).

Following a Financial Discussion held on October 21, 2024, Party L informed representatives of Jefferies that they were no longer interested in a potential transaction with IAS, citing concerns with IAS’s growth outlook as well as downward pricing pressure.

On October 22, 2024, Party B submitted a non-binding, all-cash indication of interest to the Company Board to acquire 100% of the Company Common Stock of IAS for $12.00 per share, which noted that Party B would need to conduct further due diligence and would finance the transaction through a combination of debt and equity.

On October 22, 2024, Party F verbally expressed to representatives of Jefferies that while they remained potentially interested in a transaction with IAS, they would not be willing to pay a premium to IAS’s then-current stock price.

On October 25, 2024, representatives of Jefferies delivered a relationship disclosure letter to the Company Board, which letter addressed Jefferies’ relationships with each of Party B, Party C and Party F.

Also on October 25, 2024, the Company Board held a special meeting via videoconference with members of IAS’s senior management, representatives of Jefferies and representatives of Kirkland present. During such meeting, among other topics, representatives of Jefferies provided an update with respect to the ongoing discussions with potential financial sponsor and strategic company counterparties, including with respect to the status of the potential counterparties’ respective due diligence reviews and their preliminary assessments of IAS. Since the September 29, 2024 Company Board meeting, 23 potential counterparties, consisting of 21 of the 2024 Outreach Parties and two additional potential counterparties whom representatives of Jefferies had reached out to since the September 22, 2024 meeting of the Company Board, determined not to proceed with a potential transaction with IAS, citing a variety of factors, including the highly competitive advertising sales market, pricing pressure from competition and other macroeconomic factors, concerns about the future growth outlook and its dependence on continuous product innovation, volatility in IAS’s recent performance and IAS’s vulnerability to pricing risks associated with revenue sharing agreements with demand-side platforms (“DSPs”). As a result, the only parties contacted by representatives of Jefferies that continued to have interest in a potential strategic transaction with IAS were Party B, Party C, Party F, Party K and Party M. Representatives of Jefferies informed the Company Board that of these parties, Party B was the only party to submit a written proposal to acquire IAS, although Party C and Party F had verbally expressed interest in a potential transaction involving IAS. The Company Board discussed with representatives of Jefferies Party B’s non-binding indication of interest and the likelihood of Party B increasing its proposed purchase price from $12.00 per share of Company Common Stock. Representatives of Jefferies also reviewed with the Company Board an updated preliminary financial analysis of IAS based on the October 2024 Forecasts, and discussed the ability of certain 2024 Outreach Parties to secure financing sources or pay a premium to IAS’s then-current stock price, and their likelihood of entering into a transaction with IAS. Representatives of Jefferies also summarized the status of discussions with potential strategic companies, noting that Party K was still evaluating whether or not to proceed with a potential transaction with IAS and engagement by Party M had been limited. Following this discussion, representatives of

Jefferies left the meeting and the Company Board entered an executive session. Kirkland disclosed its existing relationships with each of Party B, Party C and Party F, and Jefferies’ relationship disclosure memo (which identified its relationships with those parties) was provided to the Company Board ahead of the meeting. The Company Board concluded that none of the relationships disclosed would affect Jefferies’ ability to serve as IAS’ financial advisor or Kirkland’s ability to serve as IAS’s legal counsel. Following this discussion, members of IAS management other than those who are directors left the meeting and the Company Board determined that IAS and its advisors should continue to engage with potential counterparties, including Party B. The Company Board then discussed the terms of the potential engagement of Jefferies, including the transaction fees payable to Jefferies, and expressed support for Jefferies’ engagement.

Later on October 25, 2024, it was reported by Bloomberg that IAS was exploring a potential sale after receiving takeover interest.

By October 25, 2024, 13 potentially interested counterparties that had executed confidentiality agreements to date had been granted access to due diligence information regarding IAS in a virtual data room, including the October 2024 Forecasts. The virtual data room was updated with additional due diligence information throughout the strategic review process. Each potential counterparty that subsequently entered into a confidentiality agreement with IAS following the October 25, 2024 Company Board meeting was granted access to the data room on the same day the party entered into a confidentiality agreement.

Also on October 25, 2024, IAS executed an engagement letter with Jefferies as its financial advisor.

Following the release of the Bloomberg article, two additional potential counterparties reached out to representatives of Jefferies on October 29, 2024 and November 1, 2024, respectively, regarding a potential transaction with IAS, both of which are financial sponsors (“Party O” and “Party P”).

On October 31, 2024, representatives of Party K attended a Financial Discussion held by representatives of IAS senior management and representatives of Jefferies.

On November 1, 2024 and November 5, 2024, IAS executed confidentiality agreements with Party O and Party P.

Between November 5 and November 6, 2024, representatives of Party B and Party K separately attended “Product Deep Dive” discussions held by IAS and representatives of Jefferies.

Also on November 6, 2024, various media sources reported that Party B was engaging in discussions related to a strategic transaction involving IAS.

On November 7, 2024, representatives of Party P attended a Management Presentation held by representatives of IAS.

On November 8, 2024, following a number of diligence sessions focused on sales and go-to-market strategies, Party B informed representatives of Jefferies that it was no longer interested in a potential transaction with IAS due to slowing growth, the highly competitive nature of the industry and resulting pricing headwinds and low cash conversion relative to IAS’s earnings before interest, taxes, depreciation and amortization (“EBITDA”).

On November 20, 2024, IAS executed a confidentiality agreement with a potential counterparty that is a financial sponsor (“Party Q”).

On November 21, 2024, representatives of Party Q attended a Management Presentation held by representatives of IAS.

On November 22, 2024, representatives of Party P attended a Financial Discussion held by representatives of IAS senior management and representatives of Jefferies.

On December 27, 2024, IAS executed a confidentiality agreement with a potential counterparty that is a financial sponsor (“Party R”).

By late December 2024, all potentially interested counterparties that had executed confidentiality agreements over the few months following the October 25, 2024 Company Board meeting had been granted access to due diligence information regarding IAS in a virtual data room, including the October 2024 Forecasts.

On January 17, 2025, the Company Board held a special meeting via videoconference with representatives of Jefferies, members of IAS senior management and representatives of Kirkland to provide an update on the 2024 strategic review process (the “2024 Process”) as well as to discuss whether to conduct outreach to additional potential counterparties to a strategic transaction involving IAS. Representatives of Jefferies reviewed with the Company Board a list of (i) 36 recommended potential financial sponsor counterparties, of which four were financial sponsors that participated in and withdrew from the 2024 Process and (ii) 26 strategic companies, of which 13 participated in the 2024 Process. Representatives of Jefferies also reviewed with the Company Board an overview of each of the 36 recommended potential sponsor counterparties, including their historical acquisition activity profile, their perceived approach to investment and perceived equity capacity (including fund size).

On January 22, 2025, representatives of Jefferies met with members of IAS’s senior management to discuss the status of discussions with each of the 26 potential strategic company counterparties.

Over a period of several weeks starting on January 22, 2025, representatives of Jefferies, in accordance with the Company Board’s instructions at the January 17, 2025 meeting of the Company Board, commenced outreach to the potentially interested counterparties identified at the meeting, made up of a combination of financial sponsors (including Novacap) and strategic companies (the “2025 Outreach Parties”). 14 of the new potentially interested counterparties, consisting of 13 financial sponsors (including Novacap) and 1 strategic company, entered into customary confidentiality agreements, each on substantially similar terms, including, among other terms, a customary standstill provision that prohibited these parties (for an agreed upon period) from, among other things, offering to acquire IAS without the prior consent of the Company Board, except that certain of such potential counterparties could make confidential acquisition proposals directly to the Company Board at any time and the standstill would fall away after IAS entered into a definitive agreement with a third party providing for a change of control transaction of IAS. 44 of the 2025 Outreach Parties did not execute confidentiality agreements with IAS and did not participate in the 2025 strategic review process (the “2025 Process”) following the initial outreach call with representatives of Jefferies and 2 of the 2025 Outreach Parties had executed a customary confidentiality agreement with IAS during the 2024 Process.

On January 24, 2025, representatives of Jefferies reached out to Party L to reengage Party L in the 2025 Process.

On January 29, 2025, representatives of Jefferies shared a preliminary version of IAS’s 2025 Annual Operating Plan, including 3-year projections and revenue forecasts (the “February 2025 Forecasts” as discussed in further detail in the section of this information statement entitled “The Merger—Certain Company Financial Forecasts” beginning on page 42) with the Company Board for review.

On February 4, 2025, the Company Board held a special meeting via videoconference with representatives of Jefferies, members of IAS senior management and representatives of Kirkland to discuss the February 2025 Forecasts. Following discussion, the Company Board authorized sharing of the February 2025 Forecasts with potential transaction counterparties in connection with the strategic review process whom had executed acceptable confidentiality agreements.

Between February 3, 2025 and February 25, 2025, IAS executed separate confidentiality agreements with ten potential counterparties that are financial sponsors (“Party S,” “Party T,” “Party U,” “Party V,” “Party W,” “Party X,” “Party Y,” “Party Z,” Novacap, and “Party AA,” respectively) and two potential counterparties that are strategic companies (“Party BB” and “Party CC,” respectively). Between February 3, 2025 and February 28, 2025, representatives of Party R, Novacap, Party S, Party T, Party V, Party W, Party X, Party Y, Party Z, Party AA and Party BB, attended separate Management Presentations held by representatives of IAS. “Party DD,” a potential counterparty who is a strategic company, attended a joint management presentation with Party Y.

Over a period of several days starting on February 17, 2025, the February 2025 Forecasts were shared with potential counterparties.

On February 21, 2025, representatives of Party L attended a Financial Discussion held by representatives of IAS senior management and representatives of Jefferies.

Between February 24, 2025 and February 28, 2025, representatives of Party X and Party R attended separate Financial Discussions held by representatives of IAS senior management and representatives of Jefferies, and representatives of Party R attended a product demonstration held by IAS and representatives of Jefferies.

On March 3, 2025, representatives of Party Z attended a Management Presentation held by representatives of IAS and representatives of Party L attended a product demonstration held by IAS and representatives of Jefferies.

On March 4, 2025, representatives of Jefferies met with members of IAS senior management to provide an update regarding discussions with Party K.

Between March 5, 2025 and March 7, 2025, representatives of Party AA and representatives of Party BB attended separate Financial Discussions and product demonstrations held by IAS and representatives of Jefferies, and representatives of Party K and Party U attended separate Management Presentations held by representatives of IAS.

On March 10, 2025, representatives of Party R attended a follow-up financial due diligence discussion held by IAS and representatives of Jefferies.

On March 13, 2025, representatives of Party L submitted a non-binding written indicative term sheet for a $400 million convertible debt investment in IAS, the proceeds of which would be used to repurchase IAS shares in the open market (the “Party L Proposal”). The Party L Proposal was based on a $9.58 per share price at close of market on March 12, 2025 and noted that, among other things, the notes would be converted at a 25% premium to the 20-day volume weighted average price prior to announcement, subject to customary anti-dilution adjustment. The convertible debt investment contemplated granting Party L two seats on the Company Board, subject to certain limitations. The Party L Proposal was subject to further diligence to support the February 2025 Forecasts.

Also on March 13, 2025, representatives of Party R submitted a non-binding written indication of interest to acquire all of the outstanding shares of IAS in cash for an amount ranging from $10.50-$11.50 per share, representing a 16%-27% premium to the closing share price of $9.06 as of March 13, 2025 (the “Party R Proposal”). The Party R Proposal noted that they would have fully committed debt and equity financing in place at the time of signing a transaction and contemplated being in a position to sign definitive transaction documents within 30 days, subject to completion of due diligence.

On March 16, 2025, the Company Board held a special meeting via videoconference, with members of IAS’s senior management, representatives of Jefferies and representatives of Kirkland present. During such meeting, among other topics, representatives of Jefferies provided an update with respect to the ongoing discussions with potential financial sponsor and strategic company counterparties, including with respect to the status of the potential counterparties’ respective due diligence reviews and their preliminary assessments of IAS. Since the January 17, 2025 Company Board meeting, 44 of the 2025 Outreach Parties determined not to proceed with a potential transaction with IAS after the outreach call by representatives of Jefferies, six of the 2025 Outreach Parties attended a Management Presentation and subsequently determined not to proceed with a potential transaction, and two of the 2025 Outreach Parties attended additional meetings and conducted additional diligence, but ultimately determined not to proceed with a potential transaction. Some of the reasons expressed by various potential counterparties for not proceeding with a potential transaction included challenging market dynamics in the AdTech industry, the highly competitive nature of the AdTech industry, slowing growth and unfavorable pricing trends, the future growth outlook being highly dependent on new product innovation and IAS’s vulnerability to pricing risks associated with revenue sharing agreements with DSPs. As a result, Party K, Party L, Party Q, Party R and one additional potential counterparty who is a financial sponsor (“Party EE”) were the only 2025 Outreach Parties that remained potentially interested in a transaction with IAS, as of the March 16, 2024 Company Board meeting. Representatives of Jefferies reviewed with the Company Board a summary of the Party L Proposal and the Party R Proposal, including the material terms and conditions of each proposal. The Company Board authorized representatives of Jefferies to provide confidentiality agreements to a limited number of debt financing sources with respect to potentially providing acquisition financing in order to obtain a better view on the amount a financial sponsor could pay in a going private transaction of IAS, and further discussed the Party L Proposal and Party R Proposal. Following this discussion, the Company Board determined that IAS and its advisors should continue to engage with the potential counterparties, including

Party L and Party R, although the Company Board noted that the Company Board was not interested in a convertible note investment from Party L, but would continue to engage with them with respect to other potential transactions, and directed representatives of Jefferies to communicate the same to Party L.

By March 16, 2025, all 2025 Outreach Parties that had executed confidentiality agreements to date had been granted access to due diligence information regarding IAS in a virtual data room, including the February 2025 Forecasts. The virtual data room was updated with additional due diligence information throughout the 2025 Process.

On March 17, 2025, members of IAS’s senior management held a meeting with representatives of Jefferies and discussed next steps and potential timelines with respect to Party K, including potential marketing attribution use cases.

Over a period of several days starting on March 19, 2025, IAS executed confidentiality agreements with nine potential debt financing sources. Between March 25, 2025 and April 4, 2025, representatives of Jefferies held due diligence sessions with four such potential debt financing sources to discuss, among other topics, IAS’s potential leverage profile in a going private transaction.

At the direction of the Company Board, on March 20, 2025, representatives of Jefferies reached out to Party B to reengage Party B in the 2025 Process however, Party B declined to participate in the 2025 Process.

On March 25, 2025, representatives of Party R attended a due diligence session with representatives of IAS and Jefferies.

On March 26, 2025, representatives of Party Q attended a Management Presentation held by representatives of IAS.

On March 28, 2025, representatives of Party K and Party R attended separate follow-up diligence sessions held by IAS and representatives of Jefferies.

On April 2, 2025, representatives of Party L attended another meeting with representatives of Jefferies to discuss the feasibility and availability of debt financing.

On April 3, 2025, representatives of Party R attended a discussion regarding pricing trends, CTV and Publica held by IAS and representatives of Jefferies.

On July 1, 2025, representatives of Party X attended another Management Presentation held by representatives of IAS and received access to the customer cube.

On July 22, 2025, representatives of Party R attended a management discussion held by representatives of IAS.

On July 8, 2025, representatives of Novacap held a telephonic conference with representatives of IAS senior management to discuss pricing trends and IAS’s relationship with Oracle.

On July 17, 2025, representatives of Novacap held a telephonic conference with representatives of Jefferies and with representatives of IAS to discuss IAS’s financial condition

On July 23, 2025, Novacap submitted a written non-binding indication of interest to acquire all of the shares of Company Common Stock of IAS for $9.30 per share in cash (the “Novacap July 23 Proposal”), which required the execution of a 45-day exclusivity period within which it would complete its due diligence and negotiate a transaction (with a 30-day initial period and 15-day extension subject to meeting certain conditions) and delivery of lock-up and support agreements from Vista and other key stockholders.

On July 29, 2025, representatives of Party R informed representatives of Jefferies that they had determined not to proceed with a transaction with IAS due to AdTech market dynamics, pricing pressure, competition in the market and IAS’s vulnerability to pricing risks associated with revenue sharing agreements with DSPs.

On July 30, 2025, the Company Board held a special meeting by videoconference with, among others, representatives of Kirkland, Jefferies and members of IAS’s management in attendance. Representatives of Jefferies provided a recap and update on the strategic review process to date, noting that since September 2024, representatives of Jefferies contacted a total of 77 potentially interested counterparties, of which 24 (including 20 financial sponsors and four strategic companies) held discussions with IAS management. Of those 24 potential counterparties, four financial sponsors (i.e., Novacap, Party R, Party L and Party B) submitted non-binding

written indications of interest. Representatives of Jefferies also updated the Company Board that Party L and Party R had recently declined to pursue a transaction following submission of its indication of interest such that Novacap was the only remaining potential counterparty interested in proceeding with a potential transaction at this time. Representatives of Jefferies then reviewed with the Company Board a summary of the Novacap July 23 Proposal noting that, among other things, the Novacap July 23 Proposal represented a 15% premium to IAS’s 30-day volume weighted average price per share as of the date prior to the Novacap July 23 Proposal, Novacap would require third party debt financing for the transaction, Novacap had proposed a 45-day exclusivity period within which it would complete its due diligence and negotiate a transaction (with a 30-day initial period and 15-day extension subject to meeting certain conditions), and the Novacap July 23 Proposal contemplated equity rollover by members of management (in an unspecified amount). The Company Board engaged in discussion regarding the strategic review process and potential next steps, including in light of IAS’s recent performance and industry trends. The Company Board considered the fact that, 11 months prior to the announcement of the Merger Agreement, it was publicly reported by Bloomberg that IAS was working with Jefferies in exploring a potential sale after receiving takeover interest, followed shortly thereafter with various media sources reporting that a third party was engaged in discussions to acquire IAS which provided any third party not otherwise contacted by IAS or its representatives wishing to engage in discussions with IAS an opportunity to put forward a compelling proposal. After further discussion, the Company Board instructed representatives of Jefferies to inform Novacap that the Novacap July 23 Proposal was inadequate and that it would need to improve its price in order for the Company Board to engage further with Novacap. The Company Board also authorized representatives of Jefferies to reach out to certain other bidders that had previously participated in the strategic review process to gauge if they would have a renewed interest in exploring a transaction with IAS. The Company Board also instructed IAS management to review, in light of the passage of time, the long-term plan previously prepared by management and reviewed by the Company Board in connection with the strategic review process so that the Company Board could consider any updates to such plan in connection with evaluating any revised proposal from Novacap.

Following the July 30, 2025 Company Board meeting, representatives of Jefferies had a call with representatives of Novacap during which they informed Novacap, per the Company Board’s instructions, that the Novacap July 23 Proposal was inadequate and explained that Novacap would need to increase its price before the Company Board would be willing to engage further.

On July 31, 2025, representatives of Jefferies reached out to Party B again to reengage Party B in the 2025 Process, however, Party B declined to participate in the 2025 Process.

On August 11, 2025, Novacap submitted a revised, non-binding all-cash written indication of interest to acquire all of the shares of Company Common Stock of IAS for $9.80 per share (the “Novacap August 11 Proposal”).

On August 14, 2025, the Company Board held a special meeting by videoconference with, among others, representatives of Kirkland, Jefferies and members of IAS’s management in attendance. Representatives of Jefferies reviewed with the Company Board a summary of the Novacap August 11 Proposal, noting that the price of $9.80 per share of Company Common Stock represented an 18% premium to the 30-day volume weighted average price per share of Company Common Stock as of August 11, 2025, but otherwise, the terms of the Novacap August 11 Proposal were the same as the Novacap July 23 Proposal. The Company Board and representatives of Jefferies discussed Novacap’s ability to increase the proposed purchase price further based on Novacap’s ability to obtain debt financing and concluded that Novacap would need to engage with potential debt sources to obtain a more definitive view on its ability to obtain debt financing for the transaction in an amount that would enable Novacap to increase its proposed purchase price. Next, the Company Board discussed management’s latest updates to IAS’s long-range financial projections as previously requested by the Company Board reflecting IAS’s latest financial results and trends, highlighting certain assumptions underlying the different scenarios including, among other things, with respect to the assumed growth rate of IAS’s business as well as certain tailwinds and headwinds to the business associated with artificial intelligence, changes to the macroeconomic environment, execution risk associated with IAS achieving its plan and the assumed growth rates underlying the scenarios provided by management, initiatives regarding new product innovation and developments, and trends in the AdTech industry generally and IAS’s ability to navigate such trends. After discussion, the Company Board approved the updated projections (the “August 2025 Projections” as discussed in

further detail in the section of this information statement entitled “The Merger—Certain Company Financial Forecasts” beginning on page 42) for use by the Company Board to compare the standalone business of IAS to any proposals received from counterparties and for use by representatives of Jefferies in connection with its analysis of any potential transaction with Novacap.

On August 17, 2025, the Company Board held a special meeting by videoconference with, among others, representatives of Kirkland, representatives of Jefferies and members of IAS’s management in attendance. Representatives of Jefferies reviewed with the Company Board an updated preliminary financial analysis of the Novacap August 11 Proposal. The Company Board and representatives of Jefferies then discussed IAS’s financial performance generally, including factors that may be suppressing IAS’s stock price, including low cash conversion relative to EBITDA, which was previously cited by Party B during its evaluation of a potential transaction as a challenge facing IAS. Representatives of Jefferies then reviewed with the Company Board an illustrative sponsor take-private analysis and assessment of Novacap’s ability to pay and raise financing for the potential transaction. The Company Board and representatives of Jefferies discussed that allowing Novacap to engage with potential debt-financing sources may lead to an improved proposal. The Company Board instructed representatives of Jefferies to inform Novacap that the Company Board would be willing to move forward with Novacap at a purchase price of $11.00 per share and that Novacap should provide its best revised offer. In addition, the Company Board resolved to form an ad-hoc transaction committee (the “Transaction Committee”) for convenience and efficiency and not to address any potential conflicts of interest, and to appoint Rod Aliabadi, Brooke Nakatsukasa, Jill Putman and Lisa Utzschneider, all of whom had significant experience with mergers and acquisition transactions, to the Transaction Committee. The Company Board authorized the Transaction Committee to assist and oversee management with respect to negotiating a possible transaction with Novacap; provided that any potential transaction involving IAS would need to be approved by the full Company Board.

Following the August 17, 2025 Company Board meeting, as instructed by the Company Board, representatives of Jefferies had a discussion with representatives of Novacap where they communicated that Novacap would need to further increase its offer price.

On August 19, 2025, representatives of Jefferies delivered an updated relationship disclosure letter to the Company Board, which letter addressed Jefferies’ relationships with each of Vista and Novacap.

On August 20, 2025, Novacap, submitted a revised, non-binding all-cash written proposal of $10.15 per share (the “Novacap August 20 Proposal”).

On August 21, 2025, the Transaction Committee held a special meeting by videoconference with representatives of Kirkland, representatives of Jefferies and members of IAS management in attendance. Representatives of Jefferies provided an overview of the Novacap August 20 Proposal, which restated the request to enter into a 45-day period of exclusivity (with a 30-day initial period and 15-day extension subject to meeting certain conditions) and included a new requirement that the transaction be structured as a written consent deal in lieu of a shareholder meeting (with written consents to be provided by Vista Equity Partners and Atlas Venture Fund (“Atlas”)). Representatives of Kirkland discussed the legal and fiduciary considerations associated with granting exclusivity and with agreeing to structure a transaction as a written consent deal, including how it could impact the ability of a competing bidder to submit a topping bid. The Transaction Committee instructed representatives of Jefferies to reach out to a select group of parties that were previously involved in the IAS strategic review process to gauge their interest in a transaction before entering into exclusivity with Novacap. The Transaction Committee discussed various tactics for obtaining a higher offer price from Novacap, and determined to recommend to the Company Board that they inform Novacap that IAS would be willing to grant a shorter initial exclusivity period of 15 days during which they could engage with debt financing sources and conduct more comprehensive due diligence, and would expect Novacap to increase its offer before extending the exclusivity period and negotiating transaction documents.

Later in the day on August 21, 2025, the Transaction Committee sent an update email to the Company Board informing them of this recommendation. Following feedback from all other Company Board members that they were aligned with this approach, representatives of Jefferies were instructed to communicate the same to Novacap, which representatives of Jefferies did on August 21, 2025.

On August 22, 2025, following further discussions with representatives of Jefferies, Novacap verbally communicated to representatives of Jefferies that it would increase its non-binding offer price to $10.25 per share of Company Common Stock, provided that IAS grant a longer exclusivity period and move forward with negotiating transaction documents on the other terms previously discussed.

On August 22, 2025, the Company Board held a special meeting by videoconference with, among others, representatives of Kirkland, representatives of Jefferies and members of IAS management in attendance. Representatives of Jefferies reviewed with the Company Board the $10.25 per share price verbally offered by Novacap, noting that the price of $10.25 per share of Company Common Stock represented a 20% premium to the 30-day volume weighted average price per share of Company Common Stock as of August 29, 2025. The Company Board discussed various tactics for obtaining a higher offer price from Novacap, and determined to instruct representatives of Jefferies to inform Novacap that $10.25 per share of Company Common Stock is not a price at which the Company Board would be willing to transact, but if Novacap agreed to offer $10.30 per share of Company Common Stock, the Company Board would be willing to transact at such price and would (i) agree to approve the transaction via written consent of the stockholders (rather than via stockholder meeting) and (ii) grant a longer overall exclusivity period (with an initial exclusivity period of 15 days and subsequent extensions of the exclusivity period (x) by an additional 7 days if Novacap reconfirmed the offer price of $10.30 per share of Company Common Stock after the expiration of the initial 15-day exclusivity period and (y) by an additional 8 days if Novacap delivers substantially negotiated debt financing commitment letters in an amount sufficient to fund the entirety of the debt financing by the 21st day of the exclusivity period). In determining whether to grant exclusivity to Novacap, the Company Board also took into account, among other things, the facts that (a) the publication of the Bloomberg article on October 24, 2024 combined with the strategic review process that had been conducted by IAS since September 2024 had served as a thorough public market check and (b) there was likely a limit to Novacap’s willingness to continue to engage on the potential transaction without exclusivity or finalizing definitive documentation imminently.

Later on August 22, 2025, representatives of Jefferies communicated the IAS counterproposal of $10.30 per share of Company Common Stock as well as the Company Board’s agreement to approval of the transaction by written consent and the Company Board’s proposal on exclusivity to Novacap.

On the morning of August 24, 2025, Novacap verbally communicated to representatives of Jefferies that they would increase their offer price to $10.30 per share of Company Common Stock, noting this was their best and final price.

On August 25, 2025, IAS executed an exclusivity agreement with an initial exclusivity period of 15 days (with a 7-day extension if Novacap confirms prior to the end of the initial period that it intends to continue negotiating the transaction at a price no lower than $10.30 per share of Company Common Stock and a further 8-day extension if Novacap delivers substantially negotiated debt financing commitment letters in an amount sufficient to fund the entirety of the debt financing by the 21st day of the exclusivity period) and Novacap began the Phase II due diligence process.

Beginning on August 25, 2025 and continuing until signing, Novacap and representatives of Jefferies met twice a week to discuss the due diligence process. These meetings included technology, financial, customer, legal, tax (including foreign taxes) and IT diligence sessions. On September 3 and September 4, representatives of Novacap attended in-person due diligence meetings with IAS and representatives of Jefferies. Also on September 3, 2025, Novacap attended a dinner with representatives of IAS and a representative of Jefferies.

On September 7, 2025, the Company Board held a special meeting by videoconference with, among others, representatives of Kirkland, representatives of Jefferies and members of IAS’s management in attendance. Representatives of Kirkland reviewed with the Company Board certain key terms of the initial draft of the merger agreement (the “Draft Merger Agreement”) proposed to be shared with Novacap. The Draft Merger Agreement, among other things, (i) contained customary representations, warranties and covenants for a transaction involving a financial sponsor buyer, (ii) provided for customary termination rights of IAS, including to enter into an acquisition agreement for a superior proposal prior to receipt of the requisite shareholder approval of the transaction (subject to compliance with the terms of the agreement and the payment of a termination fee), and (iii) included “hell or high water” obligations with respect to achieving required regulatory approvals. The Draft Merger Agreement contemplated that the Consenting Stockholders, who together held the

requisite percentage of voting securities of IAS to approve a change of control transaction in accordance with the DGCL and IAS’s organizational documents, would deliver a written consent approving the potential transaction after signing of the Merger Agreement. Following such discussion, the Company Board approved the distribution of the Draft Merger Agreement to Novacap.

On September 9, 2025, the Draft Merger Agreement was distributed to Novacap. Also on September 9, 2025, Willkie Farr and Gallagher (“Willkie”), Novacap’s legal counsel, sent Kirkland a letter which reaffirmed Novacap’s offer price of $10.30 per share of Company Common Stock and extended exclusivity to September 22, 2025.

On September 15, 2025, representatives of Kirkland met with representatives of IAS to discuss key issues in the Merger Agreement shared by Willkie on September 12, 2025, including, among other things, (i) delivery of a support agreement by each of the Consenting Stockholders, (ii) the inside and outside dates for the transaction, (iii) regulatory efforts required to be employed by Novacap as well as the quantum of any reverse termination fee, (iv) treatment of IAS’s equity awards and (v) scope of interim operating covenants and representations and warranties. Also on September 15, 2025, representatives of Willkie sent to representatives of Kirkland initial drafts of the Equity Commitment Letter and Limited Guarantee to be executed by Novacap in connection with the proposed transaction. Representatives of Kirkland promptly shared the drafts of the Equity Commitment Letter and the Limited Guarantee with IAS and Vista.

Between September 16, 2025 and the signing of the Merger Agreement on September 24, 2025, under the direction and supervision of the Company Board and representatives of Kirkland, Ms. Utzschneider had several discussions with representatives of Novacap with respect to the treatment of IAS’s outstanding equity awards, including IAS’s outstanding and unvested Company RSUs, Company MSUs and Company Options. Ms. Utzschneider promptly updated the Company Board following these discussions. During this time, representatives of Kirkland and representatives of Willkie also held several teleconferences with respect to the treatment of IAS’s outstanding equity awards, including IAS’s outstanding and unvested Company RSUs, Company MSUs and Company Options.

Also on September 17, 2025, following instruction from the Company Board, representatives of Kirkland had a telephonic meeting with representatives of Atlas to discuss the current terms of the proposed transaction as well as the various transaction documents in connection with Atlas’ review and consideration in connection with their potential approval of a possible transaction with Novacap.

On September 18, 2025, representatives of Willkie sent to representatives of Kirkland the initial draft of the Support Agreement to be executed by Vista and certain of its affiliated funds in connection with the proposed transaction. Representatives of Kirkland promptly shared the draft of the Support Agreement with IAS and Vista. On September 18, 2025, representatives of Kirkland sent the initial draft of the IAS confidential disclosure letter to representatives of Willkie.

On September 19, 2025, the Transaction Committee held a special meeting by videoconference with, among others, representatives of Kirkland, representatives of Jefferies and members of IAS’s management in attendance. Representatives of Kirkland updated the Transaction Committee on the latest discussions with Novacap, including that Novacap had reconfirmed their $10.30 offer and that representatives of Kirkland and Willkie continued to exchange drafts of the key transaction documents. Representatives of Kirkland discussed with the Transaction Committee the key remaining points, including treatment of the equity awards and covenants regarding employee benefit matters applicable to IAS employees generally and also reminded the Transaction Committee that the draft Merger Agreement contemplated that the Consenting Stockholders would deliver a written consent approving the Merger after signing of the Merger Agreement. The Transaction Committee also discussed the various regulatory approvals required in connection with the Merger and expected closing timeline.

Also on September 19, 2025, (i) representatives of Kirkland sent the draft Merger Agreement to representatives of Atlas and incorporated Atlas’s feedback into the Draft Merger Agreement and (ii) representatives of Jefferies shared an updated relationship disclosure letter with the Company Board, which letter addressed Jefferies’ relationships with each of Vista and Novacap.

On September 21, 2025, the Company Board held a special meeting with members of IAS’s management and representatives of Jefferies and Kirkland present. Representatives of Jefferies reviewed with the Company Board Jefferies’ updated preliminary financial analyses of Novacap’s offer of $10.30 per share in cash (which

were based on the August 2025 Projections, as more fully described in the section of this information statement titled “The Merger—Certain Company Financial Forecasts” starting on page 42). Members of the Company Board discussed with representatives of Jefferies the latest status of Novacap’s diligence and the parties’ expectation to announce the transaction pre-market September 24, 2025, as well as the communications rollout package. At the meeting, the Company Board reviewed Jefferies’ updated relationship disclosure letter, which was circulated to the Company Board immediately following the September 19 meeting, and again determined that there were no conflicts that would affect the ability of Jefferies to fulfill its responsibilities as financial advisor to IAS. Representatives of Kirkland provided relationship disclosures to the Company Board. Following such disclosure, the Company Board again concurred that there were no relationships that would affect the ability of Kirkland to fulfill its responsibilities as legal advisor to IAS. Representatives of Kirkland reviewed again with the Company Board its fiduciary duties under Delaware law in connection with the potential transaction.

During a break in the Company Board meeting, the Compensation Committee of the Company Board (the “Compensation Committee”) held a meeting to review the treatment of certain outstanding equity awards of IAS, including the conversion of certain Unvested Company RSUs into cash replacement awards and treatment of the Company MSUs, with 50% converting into cash replacement awards and the remaining 50% converted into restricted limited partnership unit awards of an affiliate of Novacap that would directly or indirectly own all of the equity of IAS post-transaction. At this meeting, the members of the Compensation Committee also discussed with representatives of Kirkland certain employee-related covenants impacting employees post-closing of the transaction as well as transaction related bonuses and employee retention bonuses.

Following the meeting of the Compensation Committee, the Company Board reconvened and resumed the Company Board meeting. Representatives of Kirkland then summarized the current terms of the draft Merger Agreement and open points, including with respect to (i) the efforts Novacap was required to take to obtain regulatory approvals, including the negotiation of a “clear skies provision,” (ii) the amount of the respective termination fees payable by IAS and Novacap in certain circumstances, (iii) the proposed inside and outside dates, (iv) treatment of certain equity awards and certain employee benefits following signing and (v) negotiation and finalization of the Support Agreement with Vista.

On September 22, 2025, representatives of Willkie sent to representatives of Kirkland a draft of the Debt Commitment Letter that contemplated debt financing consisting of a term loan facility in an aggregate principal amount equal to $1 billion and a revolving credit facility in an aggregate principal amount equal to $150 million. Representatives of Kirkland promptly shared the draft of the Debt Commitment Letter with IAS and Vista.

On September 22, 2025, representatives of Kirkland sent the draft Written Consent to representatives of Atlas. Additionally, between September 19, 2025 and September 23, 2025, representatives of Kirkland and representatives of Willkie exchanged drafts of the Merger Agreement and the IAS confidential disclosure letter, the Support Agreement, the Debt Commitment Letter, the Equity Commitment Letter, the Limited Guarantee, the Written Consent and other transaction documents. During this time, representatives of Kirkland, on behalf of IAS, and representatives of Willkie, on behalf of Novacap, had several discussions with respect to, among other things, the remaining open items in the Merger Agreement and other transaction documents.

On September 23, 2025, the Company Board held a special meeting with members of IAS’s management and representatives of Jefferies and Kirkland present. Representatives of Kirkland provided the Company Board with an update on the final terms of the draft Merger Agreement following negotiations conducted with Willkie since the September 21, 2025 Company Board meeting, including with respect to the proposed treatment of equity awards and employee-related covenants. Representatives of Jefferies reviewed with the Company Board Jefferies’ financial analyses with respect to IAS and delivered its opinion (which Jefferies subsequently confirmed in writing) that, as of September 23, 2025, and based on and subject to the various assumptions made, procedures followed, matters considered and limitations and qualifications on the scope of review undertaken as described in its opinion, the Per Share Price to be received by the holders of shares of Company Common Stock pursuant to the proposed Merger Agreement was fair, from a financial point of view, to such holders (other than Parent, Merger Sub and their respective affiliates). Jefferies’ opinion is more fully described in the section of this information statement entitled “The Merger—Opinion of Jefferies LLC.” Following finalization and agreement on all transaction terms and the unanimous recommendation of the Compensation Committee with respect to the treatment of the equity awards and employee-related covenants contemplated by the Merger Agreement and following prior discussion and consideration of the Merger Agreement and the other transactions contemplated by the Merger Agreement (including the factors described in the section of this information statement entitled

“Recommendation of the Company Board; Reasons for the Merger” beginning on page 32), the members of the Company Board (i) determined that it is fair to, and in the best interests of, IAS and its stockholders, and declared it advisable, for IAS to enter into the Merger Agreement providing for the Merger in accordance with the DGCL upon the terms and subject to the conditions set forth therein, (ii) approved the execution and delivery of the Merger Agreement by IAS, the performance by IAS of its covenants and other obligations thereunder, and the consummation of the Merger and the other transactions contemplated by the Merger Agreement upon the terms and subject to the conditions set forth therein, (iii) directed that the adoption of the Merger Agreement by written consent be submitted for consideration by IAS’s stockholders in accordance with the Merger Agreement, and (iv) resolved to recommend that IAS’s stockholders approve and adopt the Merger Agreement by written consent in accordance with the DGCL. Further, the members of the Company Board approved the other documents and instruments and other agreements as contemplated by the Merger Agreement, including the Equity Commitment Letter, Limited Guarantee, Support Agreement, Debt Commitment Letter, IAS confidential disclosure letter and Written Consent.

On September 24, 2025, IAS and Novacap executed the Merger Agreement and delivered the Equity Commitment Letter and the Limited Guarantee and an executed Support Agreement for Vista. IAS delivered the final IAS confidential disclosure letter. Novacap also delivered an executed Debt Commitment Letter. Following the execution of the Merger Agreement and other transaction documents, the Consenting Stockholders delivered the Written Consent. After execution of the Merger Agreement and the other transaction documents and the delivery by the Consenting Stockholders of the written consent approving the transaction, IAS and Novacap issued a joint press release announcing the entry into the Merger Agreement before the opening of the U.S. stock exchange on September 24, 2025.

After consideration of various factors as discussed in the section entitled “The Merger—Recommendation of the Company Board; Reasons for the Merger” beginning on page 32, the Company Board unanimously (i) determined that it is fair to, and in the best interests of, IAS and its stockholders, and declared it advisable, to enter into the Merger Agreement providing for the Merger, in accordance with the DGCL; (ii) approved and declared advisable the Merger Agreement, the execution and delivery of the Merger Agreement by IAS, the performance by IAS of its covenants and other obligations thereunder, and the consummation of the Merger upon the terms and conditions set forth therein; (iii) resolved to recommend that IAS stockholders adopt the Merger Agreement and the Merger in accordance with the DGCL; and (iv) directed that the Merger Agreement be submitted to IAS’s stockholders for adoption.

In the course of the Company Board making such determinations, the Company Board and the Transaction Committee consulted with management of IAS, as well as IAS’s legal and financial advisors, and considered the following potentially positive factors, which are not intended to be exhaustive and are not presented in any relative order of importance:

The Company Board and the Transaction Committee also considered and balanced against the potentially positive factors a number of potentially negative factors concerning the Merger, including the following factors:

During its consideration of the transaction with Novacap, the Company Board and Transaction Committee were also aware of and considered that IAS’s directors and executive officers may have interests in the Merger that differ from, or are in addition to, the interests of IAS stockholders generally, as described in the section entitled “The Merger—Interests of Our Directors and Executive Officers in the Merger” beginning on page 45.

After taking into account all of the factors set forth above, as well as others, the Company Board determined that the potentially positive factors outweighed the potentially negative factors. The foregoing discussion of the factors considered by the Company Board is not intended to be exhaustive, but summarizes the material information and factors considered by the Company Board in its consideration of the Merger. The Company Board reached the decision to recommend and approve the Merger Agreement, the Merger and the other transactions contemplated by the Merger Agreement, in light of the factors described above and other factors the Company Board felt were appropriate. In view of the variety of factors and the quality and amount of information considered, the Company Board did not find it practicable to and did not quantify or otherwise assign relative weights to the specific factors considered in reaching its determination and individual members of the Company Board may have given different weights to different factors. The Company Board conducted an overall analysis of the factors described above, including thorough discussions with, and questioning of, senior management of IAS, Jefferies as financial advisor, and Kirkland as legal advisor, and considered the factors overall to be favorable to, and to support, its determinations. This explanation of the reasoning of the Company Board and certain information presented in this section is forward-looking in nature and should be read in light of the factors set forth in the section entitled “Cautionary Statement Regarding Forward-Looking Statements” beginning on page 17.

Under the DGCL and IAS’s Charter, the adoption of the Merger Agreement by our stockholders required the affirmative vote or written consent of stockholders of IAS holding in the aggregate at least a majority of the voting power of the outstanding shares of Company Common Stock entitled to vote thereon. Holders of Company Common Stock are entitled to one vote for each share held of record on all matters on which stockholders are entitled to vote generally, including adoption of the Merger Agreement.

On September 24, 2025, immediately following the execution of the Merger Agreement, the Consenting Stockholders, which on September 24, 2025 beneficially owned 87,732,772 shares of Company Common Stock representing approximately 52.6% of the aggregate voting power of the then issued and outstanding shares of Company Common Stock, delivered the Written Consent to IAS, a copy of which was provided to Parent in accordance with the terms of the Merger Agreement. As a result, no further action by any stockholder of IAS is required under applicable law or the Merger Agreement (or otherwise) to adopt the Merger Agreement, and IAS will not be soliciting your vote for or consent to the adoption of the Merger Agreement and the approval of the transactions contemplated by the Merger Agreement and will not call a stockholders’ meeting for purposes of voting on the adoption of the Merger Agreement and the approval of the transactions contemplated by the Merger Agreement. No action by the stockholders of Parent is required to complete the Merger and all requisite corporate action by and on behalf of Merger Sub required to complete the Merger has been taken.

When actions are taken by the written consent of less than all of the stockholders entitled to vote on a matter, Delaware law requires notice of the action be given to those stockholders who did not consent in writing to the action and who, if the action had been taken at a meeting, would have been entitled to notice of the meeting if the record date for notice of such meeting had been the date that consents signed by a sufficient number of holders to take the action were delivered to the corporation in accordance with Section 228 of the DGCL. This information statement and the notice attached hereto constitute notice to you from IAS of the Written Consent as required by Delaware law.

IAS retained Jefferies as its financial advisor in connection with a possible sale, disposition or other business transaction involving IAS. In connection with this engagement, IAS requested that Jefferies evaluate the fairness, from a financial point of view, to the holders of shares of Company Common Stock of the Per Share Price to be received by such holders (other than Parent, Merger Sub and their respective affiliates) pursuant to the Merger Agreement. At a meeting of the Company Board held on September 23, 2025, Jefferies rendered its opinion to the Company Board to the effect that, as of that date and based on and subject to the various assumptions made, procedures followed, matters considered and limitations and qualifications on the review undertaken as described in its opinion, the Per Share Price to be received by the holders of shares of Company Common Stock pursuant to the Merger Agreement was fair, from a financial point of view, to such holders (other than Parent, Merger Sub and their respective affiliates).

The full text of Jefferies’ opinion, which describes the various assumptions made, procedures followed, matters considered and limitations and qualifications on the review undertaken by Jefferies, is attached as Annex B to this information statement and is incorporated herein by reference. IAS encourages you to read the opinion carefully and in its entirety.

Jefferies’ opinion was provided for the use and benefit of the Company Board (in its capacity as such) in its evaluation of the Per Share Price from a financial point of view and did not address any other aspect of the Merger or any other matter. Jefferies’ opinion did not address the relative merits of the Merger as compared to any alternative transaction or opportunity that might be available to IAS, nor did it address the underlying business decision by IAS to engage in the Merger or any term, aspect or implication of any other agreement (or amendment thereto or related arrangements) entered into in connection with, or contemplated by or resulting from, the Merger or otherwise. Jefferies’ opinion did not constitute a recommendation as to how or whether the Company Board or any holder of shares of Company Common Stock should vote on, consent to, or otherwise act with respect to, the Merger or any other matter. The following summary is qualified in its entirety by reference to the full text of Jefferies’ opinion.

In arriving at its opinion, Jefferies, among other things:

In Jefferies’ review and analysis and in rendering its opinion, Jefferies assumed and relied upon, but did not assume any responsibility to independently investigate or verify, the accuracy and completeness of all financial and other information that was supplied or otherwise made available to Jefferies by IAS or that was publicly available to Jefferies (including, without limitation, the information described above), or that was otherwise reviewed by Jefferies. Jefferies relied on assurances of the management of IAS that it was not aware of any facts or circumstances that would make any of the foregoing information incomplete, inaccurate or misleading. In its review, Jefferies did not obtain any independent evaluation or appraisal of any of the assets or liabilities (contingent, accrued, derivative, off-balance sheet or otherwise), nor did Jefferies conduct a physical inspection of any of the properties or facilities of, IAS, and Jefferies was not furnished with and assumed no responsibility to obtain, any such evaluations, appraisals or physical inspections. Jefferies did not evaluate the solvency or fair value of IAS, Parent or any other entity under any laws relating to bankruptcy, insolvency or similar matters.

With respect to the financial forecasts provided to and reviewed by Jefferies, Jefferies noted that projecting future results of any company is inherently subject to uncertainty. However, Jefferies was advised, and Jefferies assumed, that such financial forecasts were reasonably prepared on bases reflecting the best currently available estimates and good faith judgments of the management of IAS as to the future financial performance of IAS and the other matters covered thereby. Jefferies expressed no opinion as to IAS’s financial forecasts or the assumptions on which they were based.

Jefferies’ opinion was based on economic, monetary, regulatory, market and other conditions existing and which could be evaluated as of the date thereof. Jefferies expressly disclaimed any undertaking or obligation to advise any person of any change in any fact or matter affecting Jefferies’ opinion of which Jefferies becomes aware after the date thereof.

Jefferies made no independent investigation of, and Jefferies expressed no view or opinion as to, any legal, regulatory, accounting or tax matters affecting or relating to IAS, and Jefferies assumed the correctness in all respects material to its analyses and opinion of all legal, regulatory, accounting and tax advice given to IAS and its Board of Directors, including, without limitation, with respect to changes in, or the impact of, accounting standards or tax and other laws, regulations and governmental and legislative policies affecting IAS or the Merger and legal, regulatory, accounting and tax consequences of the terms of, and transactions contemplated by, the Merger Agreement and related documents to IAS and its stockholders. In addition, in preparing its opinion, Jefferies did not take into account any tax consequences of the transaction to any holder of Company Common Stock. Jefferies assumed that the Merger would be consummated in accordance with the terms of the Merger Agreement without waiver, modification or amendment of any term, condition or agreement and in compliance with all applicable laws, documents and other requirements and that the final form of the Merger Agreement would be substantially similar to the last draft reviewed by Jefferies. Jefferies also assumed that in the course of obtaining the necessary governmental, regulatory or third-party approvals, consents, waivers and releases for the Merger or otherwise, including with respect to any divestitures or other requirements, no delay, limitation, restriction or condition would be imposed or occur that would have an adverse effect on IAS, Parent or the contemplated benefits of the Merger or that otherwise would be material in any respect to Jefferies’ analyses or opinion.

Jefferies’ opinion did not address the relative merits of the transactions contemplated by the Merger Agreement as compared to any alternative transaction or opportunity that might be available to IAS, nor did it address the underlying business decision by IAS to engage in the Merger or the terms of the Merger Agreement or the documents referred to therein, including the form or structure of the Merger or any term, aspect or implication of any other agreements, arrangements or understandings entered into in connection with, or contemplated by or resulting from the Merger or otherwise. Jefferies’ opinion did not constitute a recommendation as to how or whether any holder of shares of Company Common Stock should vote on, consent to, or otherwise act with respect to, the Merger or any matter related thereto. Jefferies was not asked to address, and its opinion did not address, the fairness to, or any other consideration of, the holders of any class of securities, creditors or other constituencies of IAS or any other party, other than the holders of shares of Company Common Stock. Jefferies expressed no view or opinion as to the price at which shares of Company Common Stock would trade or otherwise be transferrable at any time. Furthermore, Jefferies did not express any view or opinion as to the fairness, financial or otherwise, of the amount or nature of any compensation or other consideration payable to or to be received by any of IAS’s officers, directors or employees, or any class of such persons, in connection with the Merger relative to the Per Share Price to be received by holders of shares of Company Common Stock or otherwise. Jefferies’ opinion was authorized by the Fairness Committee of Jefferies LLC.

In connection with rendering its opinion to the Company Board, Jefferies performed certain financial and comparative analyses, including those described below. The following summary is not a complete description of all analyses performed and factors considered by Jefferies in connection with its opinion. The preparation of a financial opinion is a complex process involving subjective judgments and is not necessarily susceptible to partial analysis or summary description. With respect to the selected public companies and selected transactions analyses summarized below, no company used as a comparison was identical or directly comparable to IAS. These analyses necessarily involved complex considerations and judgments concerning financing characteristics and other factors that could affect the public trading or other values of the companies concerned.

Jefferies believes that its analyses and the summary below must be considered as a whole and in context and that selecting portions of its analyses and factors or focusing on information presented in tabular format, without considering all analyses and factors or the narrative description of the analyses, could create a misleading or

incomplete view of the processes underlying Jefferies’ analyses and opinion. Jefferies did not draw, in isolation, conclusions from or with regard to any one factor or method of analysis for purposes of its opinion, but rather arrived at its ultimate opinion based on the results of all analyses undertaken by it and assessed as a whole.

The estimates of the future performance of IAS in or underlying Jefferies’ analyses are not necessarily indicative of future results or values, which may be significantly more or less favorable than those estimates. In performing its analyses, Jefferies considered industry performance, general business and economic conditions and other matters, many of which are beyond the control of IAS. Estimates of the financial value of companies or businesses do not purport to be appraisals or necessarily reflect the prices at which companies, businesses or securities actually may be sold or acquired. Accordingly, the estimates used in, and the implied reference ranges resulting from, any particular analysis described below are inherently subject to substantial uncertainty and should not be taken as Jefferies’ view of the actual value of IAS or its businesses or securities.

The terms of the Merger were determined through negotiations between IAS, on one hand, and Parent and Merger Sub, on the other hand, and the decision by IAS to enter into the Merger Agreement was solely that of the Company Board. Jefferies’ opinion and financial analyses were only one of many factors considered by the Company Board in its evaluation of the Per Share Price and should not be viewed as determinative of the views of the Company Board or IAS management with respect to the Merger or the Per Share Price payable in the Merger.

The summary of the financial analyses described in this section is a summary of the material financial analyses reviewed with the Company Board and performed by Jefferies in connection with its analyses and opinion. The financial analyses summarized below include information presented in tabular format. In order to fully understand Jefferies’ financial analyses, the tables must be read together with the text of each summary. The tables alone do not constitute a complete description of the financial analyses. Considering the data below without considering the full narrative description of the financial analyses, including the methodologies and assumptions underlying the analyses, could create a misleading or incomplete view of Jefferies’ financial analyses. The order in which the financial analyses summarized below appear does not necessarily reflect the relative importance or weight given to such analyses. The following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before September 22, 2025, and is not necessarily indicative of current or future market conditions.

Jefferies reviewed publicly available financial, stock market and operating information of IAS and the following seven selected publicly traded companies in the advertising technology industry that have financial and operating characteristics that Jefferies, in its professional judgment, considered generally relevant for purposes of its analysis, which are collectively referred to as the “selected companies”:

Jefferies reviewed, among other information and to the extent publicly available, enterprise values (“EVs”) of the selected companies, calculated as fully diluted equity values based on closing stock prices on September 22, 2025, plus total debt, capital leases, preferred equity and non-controlling interests, minus cash and cash equivalents, as a multiple of each company’s estimated earnings before interest, taxes, depreciation and amortization, as applicable (“Adjusted EBITDA”), for the calendar years 2025 and 2026, which Jefferies refers to as CY 2025E and CY 2026E, respectively. Financial data of the selected companies were based on publicly available research analysts’ estimates, public filings and other publicly available information.

The financial data reviewed included the following:

Jefferies applied a selected range of enterprise value to estimated Adjusted EBITDA multiples of 7.0x to 10.0x and 6.0x to 8.0x to corresponding data of IAS based on the IAS Forecasts for estimated Adjusted EBITDA for CY 2025E and CY 2026E, respectively, unburdened by stock-based compensation expense and unburdened by capitalized software, to determine ranges of implied enterprise values for IAS. Jefferies then subtracted IAS’s estimated net debt, preferred equity and minority interest as of September 30, 2025 to calculate a range of implied equity values, and divided the result by the number of fully diluted shares of Company Common Stock outstanding, each as provided by IAS management, to calculate a range of implied per share equity values for IAS. This analysis indicated the reference ranges of implied per share equity values set forth in the table below, in each case as compared to the Per Share Price of $10.30 per share.

No company utilized in the selected public companies analysis is identical to IAS. In evaluating the selected public companies, Jefferies made judgments and assumptions with regard to industry performance, general business, economic, market and financial conditions and other matters, many of which are beyond IAS’s and Jefferies’ control.

Jefferies reviewed publicly available financial, stock market and operating information of IAS and company filings, definitive proxy statements, press releases and Wall Street research relating to the following eight historical M&A transactions, announced since September 2017, involving companies in the advertising technology industry that have financial and operating characteristics that Jefferies, in its professional judgment, considered generally relevant for purposes of its analysis, which are collectively referred to as the “selected transactions”:

The financial data reviewed included the following:

Jefferies applied a selected range of enterprise value to the last twelve months (“LTM”) Adjusted EBITDA multiples derived from the selected transactions analysis of 7.5x to 11.5x to the estimated LTM Adjusted EBITDA of IAS for the twelve months ended September 30, 2025 to determine a range of implied enterprise values for IAS. Jefferies then subtracted IAS’s estimated net debt, preferred equity and minority interest as of September 30, 2025 to calculate a range of implied equity values, and divided the result by the number of fully diluted shares of Company Common Stock outstanding, each as provided by IAS management, to calculate a range of implied per share equity values. This analysis indicated the reference ranges of implied per share equity values set forth in the table below, in each case as compared to the Per Share Price of $10.30 per share.

No transaction utilized as a comparison in the selected transactions analysis is identical to the Merger. In evaluating the Merger, Jefferies made numerous judgments and assumptions with regard to industry performance, general business, economic, market, and financial conditions and other matters, many of which are beyond the control of IAS and Jefferies.

Jefferies performed a discounted cash flow analysis of IAS by calculating the estimated present value of the stand-alone unlevered free cashflows that IAS was forecasted to generate during the fourth quarter of calendar year 2025 and the calendar years ending December 31, 2026, through December 31, 2029, based on the IAS Forecasts (and burdened by stock-based compensation expense). The terminal values of IAS were calculated by applying a selected range of perpetuity growth rates of 5.5% to 6.5% to IAS’s estimated terminal year unlevered free cashflows, based on the IAS Forecasts and per management guidance. The present values of the unlevered free cash flows and terminal values of IAS were then calculated using a selected discount rate range of 11.2% to 12.2%, based on an estimate of IAS’s weighted average cost of capital, to determine a range of implied enterprise values for IAS. Jefferies then subtracted IAS’s estimated net debt, preferred equity and minority interest as of September 30, 2025, to calculate a range of implied equity values, and divided the result by the number of fully diluted shares of Company Common Stock outstanding, each as provided by IAS management, to calculate a range of implied per share equity values for IAS. This analysis indicated a reference range of implied per share equity values of $7.81 to $10.64 per share, as compared to the Per Share Price of $10.30 per share.

IAS has agreed to pay Jefferies for its financial advisory services in connection with the Merger an aggregate fee of approximately $22.5 million, $3.0 million of which became payable upon the delivery of Jefferies’ opinion and the balance of which is payable contingent upon the Closing. In addition, IAS agreed to reimburse Jefferies for expenses, including fees and expenses of counsel, incurred in connection with Jefferies’ engagement and to indemnify Jefferies and related parties against liabilities, including liabilities under federal securities laws, arising out of or in connection with the services rendered and to be rendered by Jefferies under its engagement.

As the Company Board was aware, during the two-year period prior to the date of Jefferies’ opinion, Jefferies and its affiliates have not provided investment banking services to IAS (other than in connection with Jefferies’ current engagement) for which Jefferies and its affiliates have received compensation. During the two-year period prior to the date of Jefferies’ opinion, Jefferies and its affiliates have provided financial advisory and financing services to Novacap and Vista and/or certain of their respective affiliates and portfolio companies, for which Jefferies and its affiliates have received aggregate compensation of approximately $2.0 million and

$19.1 million, respectively. Jefferies and its affiliates may provide financial advisory and/or financing services to IAS, Novacap, Vista and/or their respective affiliates and portfolio companies in the future, for which services Jefferies and its affiliates would expect to receive compensation. In the ordinary course of Jefferies’ business, Jefferies and its affiliates may trade or hold securities or financial instruments (including loans and other obligations) of IAS, Novacap, Vista and/or their respective affiliates and portfolio companies for Jefferies’ own account and for the accounts of Jefferies’ customers and, accordingly, may at any time hold long or short positions in those securities.

Jefferies was selected as IAS’s financial advisor in connection with the Merger because, among other things, Jefferies is an internationally recognized investment banking firm with substantial experience in mergers and acquisition transactions and based on its familiarity with IAS’s business and industry. Jefferies is regularly engaged in the valuation of businesses and their securities in connection with mergers, acquisitions, negotiated underwritings, competitive bids, secondary distributions of listed and unlisted securities and private placements.

IAS does not generally publish its business plans and strategies or make external disclosures of its anticipated financial position or results of operations given, among other things, the inherent difficulty of predicting financial performance for future periods and the likelihood that the underlying assumptions and estimates may not be realized, other than for providing, from time to time, estimates of certain expected financial results and operational metrics in its regular annual and quarterly earnings press releases and other investor materials. Projections as to future performance, revenues, earnings or other results, particularly for extended time periods further in the future, are inherently uncertain and unpredictable, including due to the subjectivity of the underlying assumptions and estimates. As a result, IAS does not endorse projections or other unaudited prospective financial information as a reliable indication of future results.

In connection with ‎its consideration of its stand-alone prospects and potential strategic transactions available to ‎IAS and the process leading up to the evaluation of the Merger, IAS’s management developed, among other things, certain forward-looking forecasts with respect to fiscal years 2024 through 2027 which were prepared by IAS management and reviewed and approved for use by the Company Board on September 29, 2024, which were further refined by IAS management and shared with the Company Board on October 5, 2024 (the “2024 Forecasts”) (as described in the section entitled “—Background of the Merger” beginning on page 20) in connection with the Company Board’s evaluation of the strategic review process, and, subsequently provided to representatives of Jefferies. Subsequently, at the direction of the Company Board, due to the passage of time and changes in market conditions and related performance and outlook, IAS’s management provided the Company Board and representatives of Jefferies with updated financial forecasts with respect to fiscal years 2025 through 2027 which were reviewed and approved by the Company Board on February 4, 2025 (the “February 2025 Forecasts”) in connection with the Company Board’s evaluation of its stand-alone prospects and the strategic review process as well as for use by representatives of Jefferies in connection with its financial analyses. In August 2025, IAS’s management provided the Company Board and representatives of Jefferies with updated financial forecasts with respect to fiscal years 2025 through 2029 which were reviewed and approved by the Company Board on August 14, 2025 (the “August 2025 Forecasts” and together with the 2024 Forecasts and the February 2025 Forecasts, the “Forecasts”) in connection with the Company Board’s evaluation of the proposed Merger as well as for use by representatives of Jefferies in connection with its financial analyses and opinion (as described in the section entitled “Opinion of Jefferies LLC”).

The Forecasts included in this information statement have been prepared by IAS’s management and are subjective in many respects. The financial forecasts reflect numerous assumptions including IAS’s continued standalone operation and other relevant factors relating to IAS’s strategic plan and were not prepared with a view to public disclosure and are included in this information statement only because such information was made available to the Company Board and to representatives of Jefferies, as described herein. The Forecasts were not prepared with a view to compliance with generally accepted accounting principles as applied in the United States, which we refer to herein as “GAAP,” the published guidelines of the SEC regarding projections and forward-looking statements or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information. Furthermore, the Forecasts do not take into account any circumstances or events occurring after the date they were prepared, including the Merger. The Forecasts are not fact and should not be relied upon as being necessarily indicative of future results, and readers of this information statement are cautioned not to place undue reliance on this information. Although

this summary of the Forecasts is presented with numerical specificity, the Forecasts reflect numerous variables, assumptions and estimates as to future events made by IAS’s management that IAS’s management believed were reasonable at the time the Forecasts were prepared, taking into account the relevant information available to management at the time. Because the Forecasts cover multiple years, by their nature, they become subject to greater uncertainty with each successive year. The Forecasts reflect numerous estimates and assumptions with respect to industry performance, general business, economic, regulatory, market and financial conditions and other future events, as well as matters specific to IAS’s business, all of which are difficult to predict and inherently uncertain, and many of which are beyond IAS’s control. The Forecasts also reflect assumptions as to certain business strategies or plans that are subject to change. As a result, the Forecasts may not be realized and actual results may be significantly higher or lower than projected. The Forecasts are subjective in many respects and thus are susceptible to multiple interpretations and periodic revisions based on actual experience and business developments.

As such, the financial forecasts constitute forward-looking information and are subject to risks and uncertainties, including the various risks set forth in IAS’s Annual Report on Form 10-K for the year ended December 31, 2024, IAS’s Quarterly Reports on Form 10-Q for the quarters ended March 31, 2025 and June 30, 2025, and the other reports filed by IAS with the SEC, as well as the section entitled “Cautionary Statement Regarding Forward-Looking Statements” elsewhere in this information statement.

The Forecasts included in this document have been prepared by, and are the responsibility of, IAS's management. PricewaterhouseCoopers LLP has not audited, reviewed, examined, compiled nor applied agreed-upon procedures with respect to the accompanying Forecasts and, accordingly, PricewaterhouseCoopers LLP does not express an opinion or any other form of assurance with respect thereto. The PricewaterhouseCoopers LLP report incorporated by reference relates to IAS's previously issued financial statements. It does not extend to the Forecasts and should not be read to do so.

The inclusion of this information should not be regarded as an indication that the Company Board, IAS management, Jefferies, their respective representatives and affiliates or any other recipient of this information considered, or now considers, the Forecasts to be predictive of actual future results and should not be relied on as such. Results may differ materially (and will differ materially if the Merger is completed) from the Forecasts.

Except to the extent required by applicable federal securities laws, IAS does not intend, and expressly disclaims any responsibility, to update or otherwise revise the financial forecasts to reflect circumstances existing after the date when management prepared the financial forecasts or to reflect the occurrence of future events or changes in general economic or industry conditions, even in the event that any of the assumptions underlying the financial forecasts are shown to be in error.

The Forecasts described below are included herein because they were made available to representatives of Jefferies by IAS, and were approved by the Company Board and IAS management for representatives of Jefferies’ use in connection with Jefferies’ financial analyses and opinion, as described in the sections entitled “—Opinion of Jefferies LLC” and “—Background of the Merger,” and were made available to the Company Board in connection with its consideration of the Merger and other strategic alternatives available to IAS and, with respect to the 2024 Forecasts and the February 2025 Forecasts, were provided to certain participants in the strategic review process who remained as participants in the strategic review process at the time each of the respective Forecasts were prepared, including Parent, who received the February 2025 Forecasts, for purposes of its due diligence review of IAS, as described in the section entitled “—Background of the Merger.”

The following table summarizes the 2024 Forecasts:

The following table summarizes the February 2025 Forecasts:

The following table summarizes the August 2025 Forecasts:

Certain of the measures included in the Forecasts, including Adjusted EBITDA, are “non-GAAP financial measures,” which are financial performance measures that are not calculated in accordance with GAAP. Non-GAAP financial measures should not be considered in isolation from, or as a substitute for, financial information presented in compliance with GAAP, and non-GAAP financial measures as used by IAS may not be comparable to similarly titled measures used by other companies. The SEC rules which would otherwise require a reconciliation of a non-GAAP financial measure to a GAAP financial measure do not apply to non-GAAP financial measures included in disclosures relating to a proposed business combination such as the Merger if the disclosure is included in a document such as this information statement. IAS has not prepared, and the Company Board has not considered, a reconciliation of these non-GAAP financial measures to applicable GAAP financial measures.

Parent obtained equity and debt financing commitments for the transactions contemplated by the Merger Agreement, the aggregate proceeds of which will be sufficient for Parent to pay the aggregate Merger consideration and all related fees and expenses of IAS, Parent and Merger Sub (including in connection with the debt financing described below).

Certain investment funds affiliated with Novacap have committed, pursuant to the Equity Commitment Letter, to capitalize Parent, at or immediately prior to the Closing, with an aggregate equity contribution in an amount of up to $857,800,000, on the terms and subject to the conditions set forth in the Equity Commitment Letter. Such funds have also provided limited guarantees in favor of IAS, pursuant to the Limited Guarantee, to guarantee, subject to certain limitations set forth in the Limited Guarantee, the payment of such guarantor’s pro rata share of the obligation of Parent to pay the Parent Termination Fee, certain reimbursement obligations of Parent and Merger Sub and the reasonable out-of-pocket fees, costs and expenses incurred by IAS in connection with any suit contemplated by, and solely to the extent reimbursable under, the Merger Agreement and the Limited Guarantee.

The Lenders have committed to provide the Debt Financing in connection with the Merger consisting of a term loan facility in an aggregate principal amount equal to $1,000,000,000 and a revolving credit facility in an aggregate principal amount equal to $150,000,000, in each case, on the terms and subject to the conditions set forth in the Debt Commitment Letter. The obligations of the Lenders to provide the Debt Financing under the Debt Commitment Letter are subject to a number of conditions, including the receipt of executed loan documentation, accuracy of certain representations and warranties, consummation of the transactions contemplated by the Merger Agreement and certain equity contributions.

Parent and Merger Sub acknowledged and agreed that its obligation to consummate the transactions contemplated by the Merger Agreement on the terms and subject to the conditions set forth therein are not conditioned upon the availability or consummation of the Debt Financing (as defined in the section entitled “The

Merger Agreement—Financing Cooperation” beginning on page 66) or any other debt financing, the availability of any alternate debt financing, the availability of any equity financing or receipt of the proceeds therefrom.

You should be aware that IAS’s non-employee directors and executive officers have interests in the Merger that may be different from, or in addition to, the interests of IAS’s stockholders generally. The Company Board was aware of these interests and considered them, among other matters, in approving the Merger Agreement. These interests are described below. For purposes of the discussion below, IAS’s executive officers and named executive officers are Lisa Utzschneider (Chief Executive Officer) and Alpana Wegner (Chief Financial Officer).

Except as otherwise specifically noted, for purposes of quantifying the potential payments and benefits described in this section, the following assumptions were used:

The amounts indicated below are estimates based on multiple assumptions that may or may not actually occur or be accurate on the relevant date, including the assumptions described above, and do not reflect or attempt to forecast certain compensation actions that may occur prior to the Effective Time. As a result of the foregoing assumptions, which may or may not actually occur or be accurate on the relevant date, the actual amounts to be received by the executive officers and directors of IAS may materially differ from the amounts set forth below.

At the Effective Time, each Company Option, other than an Underwater Option, will automatically be cancelled and converted into the right to receive an amount in cash, without interest and subject to applicable withholding taxes, equal to the product of (i) the total number of shares of Company Common Stock subject to such Company Options as of immediately prior to the Effective Time and (ii) the excess, if any, of the Per Share Price over the exercise price per share of Company Common Stock of such Company Option. At the Effective Time, each Underwater Option will be cancelled for no consideration.

At the Effective Time, each Vested Company RSU will be cancelled and converted into the right to receive an amount in cash, without interest and subject to applicable withholding taxes, equal to the product of (i) the Per Share Price and (ii) the total number of shares of Company Common Stock subject to such Vested Company RSU as of immediately prior to the Effective Time.

At the Effective Time, each Unvested Company RSU will be cancelled and converted into a Converted Cash Award with respect to an amount equal to the product of (i) the Per Share Price and (ii) the total number of shares of Company Common Stock subject to such Unvested Company RSU as of immediately prior to the Effective Time. Other than as set forth in the Merger Agreement, such Converted Cash Award will continue to have, and will be subject to, the same terms and conditions (including vesting conditions) as applied to the corresponding Unvested Company RSUs immediately prior to the Effective Time, except for terms rendered inoperative by reason of the consummation of the transactions contemplated by the Merger Agreement and other administrative or ministerial changes determined by Parent.

At the Effective Time, 50% of each Company MSU will automatically be cancelled and converted into a Converted Cash Award with respect to an amount equal to the product of (i) the Per Share Price and (ii) the total number of shares of Company Common Stock subject to such Company MSU as of immediately prior to the Effective Time (with the payout factor applicable to such Company MSUs determined based on the Per Share Price). Other than as set forth in the Merger Agreement, such Converted Cash Award will continue to have, and will be subject to, the same terms and conditions (including any service-based vesting conditions and double

trigger vesting conditions, but excluding any performance-based vesting conditions) as applied to the corresponding Company MSUs immediately prior to the Effective Time, except for terms rendered inoperative by reason of the consummation of the transactions contemplated by the Merger Agreement and other administrative or ministerial changes determined by Parent.

At the Effective Time, the remaining portion of the Company MSUs outstanding as of immediately prior to the Effective Time will automatically be cancelled and converted into a Replacement Company MSU Award, with the total number of units covered by such Replacement Company MSU Award to be equal to the quotient of (i) the product of (A) the Per Share Price and (B) the total number of shares of Company Common Stock subject to such Company MSU as of immediately prior to the Effective Time (with the payout factor applicable to such Company MSU determined based on the Per Share Price), and (ii) the fair market value of such unit as of the Effective Time (based on the same price per unit paid to acquire equity in such entity in connection with the transactions contemplated by the Merger Agreement). The Replacement Company MSU Award will, subject to the holder’s continued service with Parent, the Surviving Corporation or one of its subsidiaries or a direct or indirect parent entity of Parent through the applicable vesting dates, vest and be settled at the same time the Company MSUs for which such Replacement Company MSU Award was exchanged would have vested and been settled pursuant to its terms. All Replacement Company MSU Awards will otherwise have the same terms and conditions (including service-based vesting conditions and double trigger vesting conditions, but excluding any performance-based vesting conditions) as applied to the Company MSUs for which they were exchanged, except for terms rendered inoperative by reason of the consummation of the transactions contemplated by the Merger Agreement and other administrative or ministerial changes determined by Parent; however, upon settlement of any Replacement Company MSU Award, the holder thereof will be permitted, in lieu of paying any taxes required to be withheld from such holder, to require Parent, the surviving corporation, or one of its subsidiaries or a direct or indirect parent entity of Parent, as applicable, to withhold a number of units otherwise issuable upon settlement having a fair market value equal to such required applicable withholding taxes. In addition, if a Replacement Company MSU Award is settled in connection with a termination of the award holder’s employment or service by the Surviving Corporation or its affiliates without “cause” or with “good reason” (as defined in the Replacement Company MSU Award agreement), in each case, occurring within six months following the Effective Time, then the award holder will be permitted to require the ultimate parent entity of Parent to settle the Replacement Company MSU Award in cash in place of restricted limited partnership units. Notwithstanding the foregoing, in no event will “good reason” for these purposes include or be deemed to occur upon any change of duties, responsibilities or other terms and conditions of employment that automatically occurs because IAS no longer has a class of equity securities that is publicly traded and listed on a securities exchange.

For an estimate of the amounts that would be payable to each of IAS’s named executive officers with respect to their outstanding unvested equity awards, see the section entitled “—Quantification of Potential Payments and Benefits to IAS’s Named Executive Officers in Connection with the Merger” below. The estimated aggregate value of the Unvested Company RSUs held by all non-employee directors of the Company that are outstanding on the Assumed Closing Date is $726,644.

Prior to the Effective Time, IAS will establish an executive severance plan (the “Executive Severance Plan”) consistent with the executive severance program framework previously approved by the Compensation Committee of the Company Board, which will apply to each of IAS’s executive officers. Under the Executive Severance Plan, in the event the executive officer undergoes a termination of employment without “cause” or a resignation with “good reason” (each, to be defined in the Executive Severance Plan), in either case, within six months following the Effective Time (a “CIC Termination”), then the executive officer will be entitled to receive the following:

The severance payments and benefits will be conditioned upon the executive officer’s execution and non-revocation of a general release of claims in favor of Parent, IAS and its subsidiaries, and their respective affiliates within 60 days of such termination.

Under the Executive Severance Plan, if an executive officer’s employment is terminated by the Company without “cause” or by the executive officer for “good reason” after the six-month anniversary of the Effective Time, the executive officer will remain eligible to receive a prorated annual bonus and reimbursement of the employer’s portion of COBRA premiums for the applicable severance period. However, in such case, the cash severance payments will be reduced to an amount equal to 12 months of the executive officer’s then-current base salary (or, in the case of Ms. Utzschneider, 18 months of her then-current base salary).

For an estimate of the amounts that would be payable to each of IAS’s named executive officers pursuant to the Executive Severance Plan upon a qualifying termination of employment, see the section entitled “—Quantification of Potential Payments and Benefits to IAS’s Named Executive Officers in Connection With the Merger” below.

Pursuant to the terms of the Merger Agreement, IAS may establish a cash-based retention bonus program designed to incentivize and reward continued efforts to consummate the Merger. Retention bonuses granted under the program will vest and become payable as follows: (i) 33.34% upon the Effective Time, (ii) 33.33% on the six-month anniversary of the Effective Time, and (iii) 33.33% on the 12-month anniversary of the Effective Time, in each case, subject to the recipient’s continued employment through the applicable vesting date.

With respect to Ms. Utzschneider, if her employment is terminated on or following the Effective Time (a) by IAS without “cause,” (b) due to her death or “disability,” or (c) by her for “good reason” (each as generally defined in her employment agreement), any unpaid portion of her retention award will vest and become payable, subject to her execution and non-revocation of a general release of claims in favor of Parent, IAS, and their respective subsidiaries and affiliates within 60 days following such termination.

For the amounts payable to each of IAS’s named executive officers under the retention bonus program, see “—Quantification of Potential Payments and Benefits to IAS’s Named Executive Officers in Connection With the Merger” below.

Pursuant to the terms of the Merger Agreement, notwithstanding the terms of the Executive Severance Plan, if an executive officer incurs a CIC Termination during IAS’s 2025 fiscal year, the prorated annual bonus will be determined based on the greater of (i) actual performance through December 31, 2025 (as determined by the Company Board (or a committee thereof) in its sole discretion) and (ii) target performance.

IAS may engage an expert to perform calculations regarding Sections 280G and 4999 of the United States Internal Revenue Code of 1986, as amended (the “Code”), and, subject to Parent’s approval (such approval not to be unreasonably withheld, conditioned, or delayed), implement strategies to mitigate any adverse tax consequences under Section 280G or 4999 of the Code that could arise in connection with the transactions contemplated by the Merger Agreement. However, IAS may not provide any gross-up or otherwise indemnify any individual for taxes incurred under Section 280G of the Code.

As of the date of this information statement, none of our executive officers has entered into any agreement, with Parent or any of its affiliates regarding the potential terms of their individual employment arrangements or the right to purchase or participate in the equity of Parent or one or more of its affiliates following the

consummation of the Merger. Prior to or following the Closing, however, certain executive officers may have discussions, or may enter into agreements with, Parent or its affiliates regarding employment with, or the right to purchase or participate in the equity of, Parent or one or more of its affiliates.

Pursuant to the terms of the Merger Agreement, directors and officers of IAS will be entitled to certain ongoing indemnification and insurance coverage, including under directors’ and officers’ liability insurance policies. For more information, see the section entitled “The Merger Agreement—Indemnification and Insurance” beginning on page 66.

This section sets forth the information required by Item 402(t) of Regulation S-K under the Securities Act regarding the compensation of each of IAS’s named executive officers that is based on or otherwise relates to the Merger. This compensation is referred to as “golden parachute” compensation by the applicable SEC disclosure rules, and in this section we use such term to describe the Merger-related compensation payable to IAS’s named executive officers.

The table below sets forth, for purposes of this golden parachute compensation disclosure, the potential amount of payments and benefits (on a pre-tax basis) that each of IAS’s named executive officers would receive, assuming (i) the Closing occurs on the Assumed Closing Date, (ii) each of the named executive officers experiences a CIC Termination on such date, (iii) the named executive officers’ respective base salaries and target annual bonuses remain unchanged from those that were in effect as of the date of this filing, (iv) Company Options, Company RSUs and Company MSUs held by the named executive officers that are outstanding as of the date hereof do not otherwise vest prior to the completion of the Merger, except with respect to regularly scheduled vesting dates occurring prior to the Assumed Closing Date, (v) for purposes of determining the value of Company Options, Company RSUs and Company MSUs, the value of a share of Company Common Stock is equal to the Per Share Price, (vi) no named executive officer receives any additional equity grants prior to completion of the Merger, and (vii) each named executive officer has properly executed any required releases and complied with all requirements necessary to receive the payments and benefits described below. The actual amounts to be received by any of the individuals below may materially differ from the amounts set forth below.

The payments described in the table below would be made pursuant to the arrangements described in this section.

If the Merger is completed, the Company Common Stock will be delisted from the Nasdaq and deregistered under the Exchange Act, and IAS will no longer file periodic reports with the SEC on account of the Company Common Stock.

As of the filing of this information statement, IAS is not aware of any complaints filed or litigation pending related to the Merger. Lawsuits arising out of the Merger may be filed in the future. In addition, the Company may receive stockholder demand letters pursuant to DGCL Section 220 relating to the events leading to the execution of the Merger Agreement and could receive other stockholder demand letters relating to books and records requests or the disclosure in this information statement. No assurances can be made as to the outcome of such lawsuits, demands or other actions, if any.

The following is a general discussion of certain material United States federal income tax consequences of the Merger that may be relevant to holders of Company Common Stock who exchange their shares of Company Common Stock for cash pursuant to the Merger. This discussion is based on the Code, applicable United States Treasury Regulations issued thereunder, judicial authority and administrative rulings and pronouncements, each as in effect as of the date hereof and all of which are subject to change or differing interpretations, possibly with retroactive effect. Any such change, which may or may not be retroactive, could alter the tax consequences described herein. This discussion applies only to holders whose shares of Company Common Stock are held as “capital assets” within the meaning of Section 1221 of the Code (generally, property held for investment), and does not address the tax consequences that may be relevant to holders of Company Common Stock that are subject to special tax rules, such as insurance companies, United States expatriates, controlled foreign corporations, passive foreign investment companies, holders subject to the alternative minimum tax, tax-exempt organizations, tax-qualified retirement plans or other tax-deferred accounts, broker-dealers, banks, financial institutions, regulated investment companies, real estate investment trusts, cooperatives, traders in securities that elect to apply the mark to market method of accounting, United States Holders whose functional currency is not the United States dollar, pass-through entities for United States federal income tax purposes and holders who hold Company Common Stock through such pass-through entities, holders who hold Company Common Stock as part of a hedge, straddle or conversion or other integrated transaction, holders deemed to sell Company Common Stock under the constructive sale provisions of the Code, holders required to accelerate the recognition of any item of gross income as a result of such income being recognized on an applicable financial statement, holders who exercise appraisal rights, or holders who acquired Company Common Stock pursuant to the exercise of

employee stock options or otherwise as compensation. This summary does not address (i) any aspect of state, local or non-United States taxation, and does not address any aspects of United States federal taxation other than United States federal income taxation, (ii) any tax consequences to holders of any interests in IAS other than Company Common Stock, including Company Options, Company RSUs or Company MSUs, (iii) any tax consequences of any other transaction occurring in connection with the Merger or (iv) the Medicare tax on net investment income. This discussion is not binding on the Internal Revenue Service (“IRS”) or the courts and, therefore, the conclusions set forth in this discussion could be subject to challenge, which challenge could be sustained. No ruling has been or will be sought from the IRS with respect to the Merger.

For purposes of this information statement, a “United States Holder” means a beneficial owner of Company Common Stock that is (as determined for United States federal income tax purposes):

The term “Non-United States Holder” refers to any beneficial owner of Company Common Stock, other than a partnership or other entity or arrangement treated as a partnership for United States federal income tax purposes, that is not a United States Holder.

If a partnership or other entity or arrangement treated as a partnership for United States federal income tax purposes is a holder of Company Common Stock, the United States federal income tax treatment of a partner in that partnership will generally depend upon the status of the partner and the activities of the partner and the partnership. Partners of a partnership that is a holder of Company Common Stock should consult their tax advisors as to the particular United States federal income tax consequences of the Merger to them.

The United States federal income tax consequences set forth below are included for general informational purposes only and are based upon current law as of the date hereof. Because individual circumstances may differ, each holder of Company Common Stock should consult such holder’s tax advisor to determine the applicability of the rules discussed below to such holder and the particular tax effects of the Merger to such holder, including the application and effect of United States federal, state, local and non-United States tax laws.

United States Holders. The receipt of cash pursuant to the Merger by a United States Holder in exchange for shares of Company Common Stock will be a taxable transaction for United States federal income tax purposes (and also may be a taxable transaction under applicable state, local, non-United States and other income tax laws). In general, for United States federal income tax purposes, a United States Holder who receives cash pursuant to the Merger in exchange for shares of Company Common Stock will recognize gain or loss in an amount equal to the difference between (x) the amount of cash the United States Holder receives (determined before deduction of any applicable withholding taxes) and (y) such United States Holder’s adjusted tax basis in the surrendered shares of Company Common Stock. A United States Holder’s adjusted tax basis (which generally will equal the price the United States Holder paid for such shares, and if applicable, will have been reduced by return of capital distributions). Gain or loss will be calculated separately for each block of Company Common Stock (generally shares acquired by a holder at the same cost in a single transaction) converted in the Merger. Such gain or loss generally will be capital gain or loss, and will be long-term capital gain or loss if the Company Common Stock has been held by a United States Holder for more than one year as of the Effective Time. Long-term capital gains of non-corporate United States Holders may be eligible for reduced rates of taxation. The deductibility of capital losses is limited.

Non-United States Holders. Subject to the discussion below regarding backup withholding, a Non-United States Holder that receives cash pursuant to the Merger in exchange for shares of Company Common Stock

generally is not expected to be subject to United States federal income tax on any gain realized on such exchange, unless (i) such holder is an individual who is present in the United States for 183 or more days during the taxable year of the Merger and certain other conditions are met, (ii) the gain is effectively connected with the conduct of a trade or business in the United States by the Non-United States Holder (and, in the case of certain income tax treaties, is attributable to a permanent establishment or fixed base of the Non-United States Holder within the United States) or (iii) such holder owned, directly or under certain constructive ownership rules of the Code, more than 5% of Company Common Stock at any time during the five-year period preceding the Merger, and IAS is or has been a “United States real property holding corporation” for United States federal income tax purposes at any time during the shorter of the five-year period preceding the Merger or the period that the Non-United States Holder held Company Common Stock. IAS believes it is not and has not been a “United States real property holding corporation” for United States federal income tax purposes at any time during the five-year period preceding the Merger.

If you are a Non-United States Holder who is an individual and has been present in the United States for 183 or more days during the taxable year of the Merger and certain other conditions are satisfied, you will be subject to United States federal withholding taxes, currently at a 30% rate (or such lower rate as may be specified in an applicable income tax treaty), on any gain realized, which generally may be offset by certain United States source capital losses.

If you are a Non-United States Holder and your gain is effectively connected with the conduct of a United States trade or business by you (and, in the case of certain income tax treaties, is attributable to a permanent establishment or fixed base of the Non-United States Holder within the United States), you will be subject to United States federal income tax on any gain realized on a net basis in the same manner as a United States Holder. Non-United States Holders that are corporations may also be subject to an additional “branch profits tax” on such effectively connected income, currently at a 30% rate (or such lower rate as may be specified in an applicable income tax treaty), subject to certain adjustments.

Information Reporting and Backup Withholding. Cash consideration received by a United States Holder or a Non-United States Holder in the Merger may be subject to information reporting and backup withholding. To avoid backup withholding, a United States Holder that does not otherwise establish an exemption should complete and return to the applicable paying agent an IRS Form W-9, certifying that such United States Holder is a United States person, that the taxpayer identification number provided is correct and that such United States Holder is not subject to backup withholding. A Non-United States Holder generally may establish an exemption from backup withholding by certifying its status as a non-United States person under penalties of perjury on an IRS Form W-8BEN or other applicable IRS Form W-8. Backup withholding is not an additional tax. Amounts so withheld can be credited against such holder’s federal income tax liability and may entitle such holder to a refund, provided that the required information is timely furnished to the IRS.

United States Holders and Non-United States Holders should consult their tax advisors regarding the application of United States federal income tax laws and non-United States tax laws, including information reporting and backup withholding, to their particular situations.

Additional Withholding Requirements Under the Foreign Account Tax Compliance Act. Sections 1471 through 1474 of the Code, and the United States Treasury Regulations and administrative guidance issued thereunder (collectively, “FATCA”), generally impose a United States federal withholding tax, currently at a 30% rate on certain payments made to a “foreign financial institution” (as specially defined under these rules) unless such institution enters into an agreement with the United States government to withhold on certain payments and to collect and provide to the United States tax authorities substantial information regarding certain United States account holders of such institution (which include certain equity and debt holders of such institution, as well as certain account holders that are foreign entities with United States owners) or an exemption applies. FATCA also generally imposes a United States federal withholding tax, currently at a 30% rate on certain payments made to a non-financial foreign entity unless such entity provides the withholding agent a certification identifying certain direct and indirect United States owners of the entity or an exemption applies. An intergovernmental agreement between the United States and an applicable foreign country may modify these requirements. Under certain circumstances, a Non-United States Holder might be eligible for refunds or credits of such taxes.

The United States Treasury Department has released proposed regulations which, if finalized in their present form, would eliminate the FATCA withholding applicable to the gross proceeds of a sale or other disposition of Company Common Stock. In its preamble to such proposed regulations, the United States Treasury Department stated that taxpayers may generally rely on the proposed regulations until final regulations are issued.

Holders of Company Common Stock should consult with their tax advisors regarding the possible implications of FATCA on the disposition of Company Common Stock pursuant to the Merger.

THE FOREGOING SUMMARY DOES NOT DISCUSS ALL ASPECTS OF UNITED STATES FEDERAL INCOME TAXATION THAT MAY BE RELEVANT TO PARTICULAR HOLDERS OF COMPANY COMMON STOCK. HOLDERS OF COMPANY COMMON STOCK ARE URGED TO CONSULT THEIR TAX ADVISORS AS TO THE PARTICULAR TAX CONSEQUENCES TO THEM OF THE RECEIPT OF CASH FOR THEIR SHARES OF COMPANY COMMON STOCK PURSUANT TO THE MERGER UNDER ANY UNITED STATES FEDERAL, STATE, LOCAL, NON-UNITED STATES OR OTHER TAX LAWS, OR UNDER ANY APPLICABLE INCOME TAX TREATY.

Concurrently with the execution and delivery of the Merger Agreement, Parent and IAS entered into the Support Agreement with Vista and certain investment funds affiliated with Vista. Under the Support Agreement, the stockholders party thereto have agreed, among other things, to vote or execute consents with respect to all of their shares of Company Common Stock in favor of the Merger and the other transactions contemplated by the Merger Agreement, subject to certain terms and conditions contained therein. Vista and the other parties to the Support Agreement executed consents with respect to all of their shares of Company Common Stock in favor of the Merger and the other transactions contemplated by the Merger Agreement by delivering the Written Consent. Pursuant to the Support Agreement, the parties thereto also agreed to terminate certain agreements between Vista and its affiliates, on the one hand, and IAS, on the other hand, and to modify certain surviving provisions contained therein.

The foregoing description of the Support Agreement does not purport to be complete and is qualified in ‎its entirety by reference to the complete text of the Support Agreement, a copy of which is attached as ‎Annex C to this proxy statement and which is incorporated by reference in this proxy statement in its entirety.‎

Under the Merger Agreement, each of Parent and IAS has agreed to (i) cooperate and coordinate (and cause its respective affiliates to cooperate and coordinate) with the other in the making of specified regulatory filings; (ii) supply the other (or cause the other to be supplied) with any information that may be reasonably required in order to make such filings; (iii) supply (or cause to be supplied) any additional information that may be reasonably required or requested by the FTC, the Department of Justice or the governmental authorities of any other applicable jurisdiction in which any such filing is made; and (iv) subject to certain limitations, use reasonable best efforts to take (and to cause their affiliates to take) all actions reasonably necessary, proper or advisable to (1) cause the expiration or termination of the applicable waiting periods pursuant to the HSR Act and any other antitrust laws applicable to the Merger Agreement or the Merger; and (2) obtain all clearances, consents, approvals, waivers, actions, non-actions and other authorizations pursuant to any antitrust laws and foreign investment laws applicable to the Merger Agreement or the Merger, in each case as promptly as reasonably practicable.

Subject to certain limitations, if and to the extent necessary to obtain clearances, consents, approvals, waivers, actions, waiting period expirations or terminations, non-actions or other authorizations pursuant to the HSR Act, any other antitrust laws or any foreign investment laws applicable to the Merger and to avoid or eliminate each and every impediment under the HSR Act, any other antitrust laws or any foreign investment laws applicable to the Merger, as promptly as reasonably practicable, each of Parent and Merger Sub have agreed to use their respective reasonable best efforts to avoid or eliminate each and every impediment and to obtain all clearances, consents, approvals, waivers, actions, waiting period expirations or terminations, non-actions or other authorizations under the HSR Act, any other antitrust laws or any foreign investment laws, including offering, committing to, and effectuating (i) the sale, divestiture, transfer, license disposition, or hold separate (through the establishment of a trust or otherwise), of any and all of the capital stock or other equity or voting interest, assets (whether tangible or intangible), rights, properties, products or businesses of Parent, Merger Sub, IAS or any of

its subsidiaries; (ii) the termination, modification, or assignment of existing relationships, joint ventures, contracts, or obligations of Parent, Merger Sub, IAS or any of its subsidiaries; (iii) the modification of any course of conduct regarding future operations of Parent, Merger Sub, IAS or any of its subsidiaries; and (iv) any other restrictions on the activities of Parent, Merger Sub, IAS or any of its subsidiaries, including the freedom of action of Parent, Merger Sub, IAS or any of its subsidiaries with respect to, or their ability to retain, one or more of their respective operations, divisions, businesses, product lines, customers, assets or rights or interests, or their freedom of action with respect to the assets, properties, or businesses to be acquired pursuant to the Merger Agreement; in each case, so as to allow the consummation of the Merger as soon as reasonably practicable and, in any event, prior to the Termination Date; provided that Parent, Merger Sub, IAS or any of its subsidiaries shall not be required to take any action if (x) it would reasonably be expected to have a material adverse effect on the business, results of operations or financial condition of IAS and its subsidiaries, taken as a whole or (y) otherwise involve any assets, properties, operations or businesses other than those of Parent, Merger Sub, IAS or its subsidiaries.

Under the HSR Act and related rules, certain transactions, including the Merger, may not be completed until notifications have been given and information furnished to the Antitrust Division and the FTC and all statutory waiting period requirements have been satisfied by the applicable agencies. On October 24, 2025, both IAS and Parent filed their respective notification and report forms under the HSR Act, which triggered the start of the HSR Act waiting period. The waiting period under the HSR Act will expire at 11:59 p.m. EST on November 24, 2025.

At any time before or after the Effective Time, the Antitrust Division or the FTC could take action under the antitrust laws, including seeking to prevent the Merger, to rescind the Merger or to conditionally approve the Merger upon the divestiture of assets of IAS or Parent or subject to regulatory conditions or other remedies. In addition, United States state attorneys general could take action under the antitrust laws as they deem necessary or desirable in the public interest, including, without limitation, seeking to enjoin the completion of the Merger or permitting completion subject to regulatory conditions. Private parties may also seek to take legal action under the antitrust laws under some circumstances. There can be no assurance that a challenge to the Merger on antitrust grounds will not be made or, if such a challenge is made, that it would not be successful.

The consummation of the Merger is also conditioned upon the clearance or approval by the antitrust authorities in certain specified jurisdictions and relevant authorities under certain specified foreign investment laws. The Merger cannot be completed until IAS and Parent obtain clearance to consummate the Merger or the applicable waiting periods have expired or been terminated in such jurisdictions.

There can be no assurances that all of the required regulatory approvals will be obtained and, if obtained, there can be no assurances as to the timing of any approvals, Parent’s or IAS’s ability to obtain the approvals on satisfactory terms or the absence of any litigation challenging such approvals.

This section describes the material terms and conditions of the Merger Agreement. The description in this section and elsewhere in this information statement is qualified in its entirety by reference to the complete text of the Merger Agreement, a copy of which is attached as Annex A and is incorporated by reference into this information statement. This summary does not purport to be complete and may not contain all of the information about the Merger Agreement that is important to you. We encourage you to read the Merger Agreement carefully and in its entirety. This section is not intended to provide you with factual information about IAS. Such information can be found elsewhere in this information statement and in the public filings IAS makes with the SEC, which may be obtained by following the instructions set forth in the section entitled “Where You Can Find More Information,” beginning on page 85.

The Merger Agreement has been included to provide you with information regarding its terms. It is not intended to provide any other factual information about IAS, Parent, Merger Sub or any of their respective subsidiaries or affiliates. The representations, warranties, and covenants contained in the Merger Agreement were made by the parties thereto only for the purposes of that agreement and as of specific dates; were made solely for the benefit of the parties to the Merger Agreement; may be subject to limitations agreed upon by the contracting parties, including being qualified by confidential disclosures exchanged between the parties in connection with the execution of the Merger Agreement (such disclosures include information that has been included in IAS’s public disclosures, as well as additional nonpublic information); may have been made for the purposes of allocating contractual risk between the parties to the Merger Agreement instead of establishing these matters as facts; and may be subject to standards of materiality applicable to the contracting parties that differ from those applicable to you. You should not rely on the representations, warranties and covenants or any descriptions thereof as characterizations of the actual state of facts or condition of IAS, Parent, Merger Sub or any of their respective subsidiaries or affiliates. Additionally, the representations, warranties, covenants, conditions and other terms of the Merger Agreement may be subject to subsequent waiver or modification. Moreover, information concerning the subject matter of the representations, warranties and covenants may change after the date of the Merger Agreement, which subsequent information may or may not be fully reflected in IAS’s public disclosures.

Upon the terms and subject to the conditions of the Merger Agreement, and in accordance with the DGCL, at the Effective Time, Merger Sub will be merged with and into IAS, whereupon the separate corporate existence of Merger Sub will cease, and IAS will continue as the Surviving Corporation and a wholly owned subsidiary of Parent.

The Merger will become effective at such time as the certificate of merger has been duly filed with the Secretary of State of the State of Delaware, or at such other time as Parent, Merger Sub and IAS agree in writing and specify in the certificate of merger. The Closing will take place at 9:00 a.m., New York City time, on a date to be agreed upon by Parent, Merger Sub and IAS that is no later than the third business day after the satisfaction or waiver (to the extent permitted by the Merger Agreement) of the last to be satisfied or waived of the conditions set forth in the Merger Agreement (other than those conditions that by their terms are to be satisfied at the Closing, but subject to the satisfaction or waiver (to the extent permitted by the Merger Agreement) of such conditions at the Closing). Notwithstanding the foregoing, Parent, Merger Sub and IAS have agreed that, unless otherwise agreed to in writing by Parent, the Closing shall not take place prior to November 23, 2025.

Subject to the terms and conditions of the Merger Agreement, at the Effective Time, (i) each share of common stock of Merger Sub that is issued and outstanding immediately prior to the Effective Time will automatically be cancelled and converted into and become one share of common stock of the Surviving Corporation; (ii) each share of Company Common Stock that is issued and outstanding as of immediately prior

to the Effective Time (other than Owned Company Shares or Dissenting Company Shares) will be automatically cancelled, extinguished and converted into the right to receive the Per Share Price, without interest thereon; and (iii) each share of the Owned Company Shares will automatically be cancelled and extinguished without any conversion thereof or consideration paid therefor.

Prior to the Closing, Parent will select a nationally recognized bank or trust company reasonably acceptable to IAS to act as the payment agent for the payment of the aggregate consideration to which holders of shares of Company Common Stock are entitled pursuant to the Merger Agreement, and at or prior to the Closing, Parent will deposit or cause to be deposited with the payment agent an amount in cash necessary to pay for the shares of Company Common Stock (other than Owned Company Shares or Dissenting Company Shares) converted into the right to receive the payment of the aggregate consideration to which holders of shares of Company Common Stock are entitled pursuant to the Merger Agreement. Parent may elect, at least two business days prior to the Closing date (with written notice to IAS), for IAS to deposit with the payment agent a portion of the available cash balances of IAS and its subsidiaries to satisfy all or of a portion of Parent’s obligation to make available to the payment agent cash sufficient to pay the aggregate closing consideration.

Promptly (and in any event no later than three business days) after the Effective Time, Parent and the Surviving Corporation will cause the payment agent to send to each holder of record as of immediately prior to the Effective Time of one or more Certificates (if any) (i) a letter of transmittal in customary form (which will specify that delivery will be effected, and risk of loss and title to the Certificates will pass, only upon delivery of the Certificates to the payment agent) and (ii) instructions for effecting the surrender of the Certificates in exchange for the Per Share Price payable with respect to the shares of Company Common Stock formerly represented by the Certificates. Upon surrender of Certificates for cancellation to the payment agent, together with such letter of transmittal, duly completed and validly executed in accordance with the instructions thereto, the holders of such Certificates will be entitled to receive in exchange therefor an amount in cash equal to the product obtained by multiplying (x) the aggregate number of shares of Company Common Stock represented by such Certificates by (y) the Per Share Price, and the Certificates so surrendered will be cancelled. With respect to record holders of Uncertificated Shares, upon the payment agent’s receipt of an “agent’s message” (or such other evidence as the payment agent may reasonably request), the holder of such Uncertificated Shares will be entitled to receive in exchange an amount in cash equal to the product obtained by multiplying (1) the aggregate number of shares of Company Common Stock represented by such holder’s transferred Uncertificated Shares by (2) the Per Share Price, and the transferred Uncertificated Shares will be cancelled. No dividends or other distributions with respect to capital stock of the Surviving Corporation with a date on or after the Effective Time will be paid to the holder of any unsurrendered Certificates or Uncertificated Shares.

At or prior to the Closing, Parent will deposit (or cause to be deposited) with IAS, by wire transfer of immediately available funds, the aggregate consideration owed to all holders of Company Options and Vested Company RSUs in respect of such Company Options and Vested Company RSUs, as applicable (the “Vested Equity Award Consideration”); provided that Parent may elect, at least two business days prior to the Closing date (with written notice to IAS), for IAS to deposit with the payment agent a portion of the available cash balances of IAS and its subsidiaries to satisfy all or a portion of Parent’s obligation to make available to the payment agent cash sufficient to pay the Vested Equity Award Consideration. As promptly as reasonably practicable, but in any event in no less than seven business days after the Closing date, the Vested Equity Award Holders (as defined in the Merger Agreement) will be paid by IAS or the Surviving Corporation, through its payroll system or payroll provider, all amounts required to be paid to such holders in respect of Company Options and Vested Company RSUs that are cancelled and converted into a cash payment, less any required withholdings.

Each of the Surviving Corporation, IAS, Parent and the payment agent will be entitled to deduct and withhold from any cash amounts otherwise payable pursuant to the Merger Agreement to any holder or former holder of shares of Company Common Stock, Company Options, Company RSUs and Company MSUs, such amounts as may be required to be deducted and withheld under applicable law with respect to taxes. Any amounts so deducted or withheld and paid over to the appropriate governmental authority and will be treated for all purposes as having been paid to the person in respect of which such deduction or withholding was made.

At the Effective Time, each Company Option, other than an Underwater Option, will automatically be cancelled and converted into the right to receive an amount in cash, without interest and subject to applicable withholding taxes, equal to the product of (i) the total number of shares of Company Common Stock subject to such Company Options as of immediately prior to the Effective Time and (ii) the excess, if any, of the Per Share Price over the exercise price per share of Company Common Stock of such Company Option. At the Effective Time, each Underwater Option will be cancelled for no consideration.

At the Effective Time, each Vested Company RSU will be cancelled and converted into the right to receive an amount in cash, without interest and subject to applicable withholding taxes, equal to the product of (i) the Per Share Price and (ii) the total number of shares of Company Common Stock subject to such Vested Company RSU as of immediately prior to the Effective Time.

At the Effective Time, each Unvested Company RSU will be cancelled and converted into a Converted Cash Award with respect to an amount equal to the product of (i) the Per Share Price and (ii) the total number of shares of Company Common Stock subject to such Unvested Company RSU as of immediately prior to the Effective Time. Other than as set forth in the Merger Agreement, Converted Cash Award will continue to have, and will be subject to, the same terms and conditions (including vesting conditions) as applied to the corresponding Unvested Company RSU immediately prior to the Effective Time, except for terms rendered inoperative by reason of the consummation of the transactions contemplated by the Merger Agreement and other administrative or ministerial changes determined by Parent.

At the Effective Time, 50% of each Company MSU will automatically be cancelled and converted into a Converted Cash Award with respect to an amount equal to the product of (i) the Per Share Price and (ii) the total number of shares of Company Common Stock subject to such Company MSU as of immediately prior to the Effective Time (with the payout factor applicable to such Company MSU determined based on the Per Share Price). Other than as set forth in the Merger Agreement, Converted Cash Award will continue to have, and will be subject to, the same terms and conditions (including any service-based vesting conditions and double trigger vesting conditions, but excluding any performance-based vesting conditions) as applied to the corresponding Company MSU immediately prior to the Effective Time, except for terms rendered inoperative by reason of the consummation of the transactions contemplated by the Merger Agreement and other administrative or ministerial changes determined by Parent.

At the Effective Time, the remaining portion of the Company MSUs outstanding as of immediately prior to the Effective Time will automatically be cancelled and converted into a Replacement Company MSU Award, with the total number of units covered by such Replacement Company MSU Award to be equal to the quotient of (i) the product of (A) the Per Share Price and (B) the total number of shares of Company Common Stock subject to such Company MSU as of immediately prior to the Effective Time (with the payout factor applicable to such Company MSU determined based on the Per Share Price), and (ii) the fair market value of such unit as of the Effective Time (based on the same price per unit paid to acquire equity in such entity in connection with the transactions contemplated by the Merger Agreement). The Replacement Company MSU Award will, subject to the holder’s continued service with Parent, the Surviving Corporation or one of its subsidiaries or a direct or indirect parent entity of Parent through the applicable vesting dates, vest and be settled at the same time the Company MSUs for which such Replacement Company MSU Award was exchanged would have vested and been settled pursuant to its terms. All Replacement Company MSU Awards will otherwise have the same terms and conditions (including service-based vesting conditions and double trigger vesting conditions, but excluding any performance-based vesting conditions) as applied to the Company MSUs for which they were exchanged, except for terms rendered inoperative by reason of the consummation of the transactions contemplated by the Merger Agreement and other administrative or ministerial changes determined by Parent; however, upon settlement of any Replacement Company MSU Award, the holder thereof will be permitted, in lieu of paying any taxes required to be withheld from such holder, to require Parent, the surviving corporation, or one of its subsidiaries or a direct or indirect parent entity of Parent, as applicable, to withhold a number of units otherwise issuable upon settlement having a fair market value equal to such required applicable withholding taxes. For additional terms applicable to Replacement Company MSU Awards, including settlement mechanics upon certain terminations within six months following the Effective Time, see the section entitled “The Merger—Interests of Our Directors and Executive Officers in the Merger” beginning on page 45.

Following the date of the Merger Agreement, no new offering periods or purchase periods may be commenced under the Company ESPP, and no employee may newly enroll in the Company ESPP or increase their contribution rates or purchase elections under the Company ESPP. If the Effective Time occurs prior to the end of any outstanding offering period in existence under the Company ESPP as of the date of the Merger Agreement, all outstanding purchase rights under the Company ESPP will automatically be exercised in accordance with the terms of the Company ESPP no later than seven calendar days prior to the Effective Time, and the Company ESPP will terminate as of immediately prior to the Effective Time. Each share of Company Common Stock purchased under the Company ESPP will be cancelled at the Effective Time and converted into the right to receive the Per Share Price in the same manner as other IAS stockholders.

If and to the extent required by the DGCL, any share of Company Common Stock that is issued and outstanding immediately prior to the Effective Time (other than the Owned Company Shares) and that is held by a holder of such share of Company Common Stock who has not voted in favor of the adoption of the Merger Agreement and who has properly exercised appraisal rights with respect thereto in accordance with, and who has complied with, Section 262 of the DGCL with respect to such Company Common Stock (collectively, the “Dissenting Company Shares”) will not be converted into the right to receive the Per Share Price, but instead holders of such Dissenting Company Shares will be entitled to receive payment of the fair value of such Dissenting Company Shares in accordance with the provisions of Section 262 unless and until such holder fails to perfect or effectively withdraws or loses its rights to appraisal and payment under the DGCL. If, after the Effective Time, any such holder fails to perfect or effectively withdraws or loses the right to appraisal under Section 262, or a court of competent jurisdiction determines that such holder is not entitled to the relief provided by Section 262, then the right of such holder to receive those rights under and to be paid such consideration as is determined pursuant to Section 262, will cease and such Dissenting Company Shares will thereupon be treated as if they had been converted into, at the Effective Time, the right to receive the Per Share Price, and the Surviving Corporation shall remain liable for payment of the Per Share Price for such Dissenting Company Shares in accordance with the Merger Agreement. IAS will provide prompt notice to Parent of any demands received by IAS for appraisal of any shares of Company Common Stock, and Parent will have the opportunity to participate in all negotiations and proceedings with respect to such demands. Except with the prior written consent of Parent, IAS will not make any payment with respect to, or settle or offer to settle, or otherwise negotiate any such demands. Parent will not, except with the prior written consent of IAS, require IAS to make any payment with respect to any demands for appraisal or offer to settle or settle any such demands.

The Merger Agreement provides that, from and after the Effective Time, all (i) of the property, rights, privileges, powers and franchises of IAS and Merger Sub will vest in the Surviving Corporation; and (ii) debts, liabilities and duties of IAS and Merger Sub will become the debts, liabilities and duties of the Surviving Corporation. If the Merger is consummated, IAS will cease to be a publicly traded company. If the Merger is consummated, you will not own any shares of capital stock of the Surviving Corporation.

At the Effective Time, (i) IAS’s Charter, as in effect immediately prior to the Effective Time, will be amended and restated in its entirety to be read as set forth in the applicable exhibit attached to the Merger Agreement and, as so amended and restated, will be the certificate of incorporation of the Surviving Corporation and (ii) the bylaws of Merger Sub as in effect immediately prior to the Effective Time will become the bylaws of the Surviving Corporation.

In addition, from and after the Effective Time until successors are duly elected or appointed and qualified in accordance with applicable law, (i) the board of directors of Merger Sub at the Effective Time will be the board of directors of the Surviving Corporation and (ii) the officers of IAS at the Effective Time will be the officers of the Surviving Corporation.

IAS, Parent and Merger Sub made representations and warranties in the Merger Agreement regarding themselves and, as applicable, their respective subsidiaries that are subject, in some cases, to specified exceptions and qualifications contained in the Merger Agreement (including “knowledge” and materiality qualifications and

qualifications referring to dollar thresholds) and are further modified and limited by a confidential disclosure letter delivered by IAS to Parent. The representations and warranties made by IAS are also subject to, and qualified by, certain information in our filings made with the SEC at least one business day before the date of the Merger Agreement.

IAS’s representations and warranties to Parent and Merger Sub in the Merger Agreement relate to, among other things:

In addition, the Merger Agreement contains representations and warranties of Parent and Merger Sub relating to, among other things:

Certain of the representations and warranties in the Merger Agreement are qualified as to “materiality” or “Company Material Adverse Effect” or words of similar import. The Merger Agreement provides that a Company Material Adverse Effect means any change, event, effect, development or occurrence that, individually or in the aggregate, has had, or would reasonably be expected to have, a material adverse effect on (x) the business, financial condition, assets, liabilities, or results of operations of IAS and its subsidiaries, taken as a whole or (y) the ability of IAS to consummate the transactions contemplated by the Merger Agreement prior to the Termination Date; provided that, solely with respect to clause (x), none of the following, and no changes, events, effects, developments or occurrences to the extent arising out of, relating to or resulting from the following (in each case, by itself or when aggregated) will be deemed to be or constitute a Company Material Adverse Effect or will be taken into account when determining whether a Company Material Adverse Effect has occurred or would reasonably be expected to occur (subject to the limitations set forth below):

Certain of Parent’s and Merger Sub’s representations and warranties in the Merger Agreement are qualified by a “Parent Material Adverse Effect” standard (that is, they will not be deemed to be untrue and incorrect unless their failure to be true and correct would reasonably be expected to have, individually or in the aggregate, a Parent Material Adverse Effect). For purposes of the Merger Agreement, a Parent Material Adverse Effect means a failure of any representations and warranties of Parent and Merger Sub to be true and correct that would, individually or in the aggregate, reasonably be expected to prevent, materially delay, or have a material adverse effect on the ability of Parent or Merger Sub to perform its obligations under the Merger Agreement or to consummate other transactions contemplated by the Merger Agreement.

IAS has agreed to certain covenants in the Merger Agreement restricting the conduct of its business from the date of the Merger Agreement until the earlier of the Effective Time or the termination of the Merger Agreement (the “Interim Period”). Except as contemplated by the Merger Agreement, as set forth in the confidential disclosure letter, as required by applicable law, or as approved by Parent in writing (which approval shall not be unreasonably withheld, conditioned or delayed), during the Interim Period, IAS shall, and shall cause each of its subsidiaries to, use its commercially reasonable efforts to (i) conduct its business in all material respects in the ordinary course of business, and (ii) preserve intact in all material respects its business organization, properties, rights and assets and relationships and goodwill with its key employees, material customers, suppliers, landlords, governmental authorities and other persons having material business relationships with IAS or its subsidiaries.

In addition, except as expressly contemplated by the Merger Agreement, as set forth in the confidential disclosure letter, as required by applicable law, or as approved by Parent in writing (which approval shall not be unreasonably withheld, conditioned or delayed), IAS shall not, and shall not permit any of its subsidiaries, to:

Each party to the Merger Agreement will (and will cause their respective affiliates to, if applicable) use its reasonable best efforts to (i) take (or cause to be taken) all actions; (ii) do (or cause to be done) all things; and (iii) assist and cooperate with the other parties in doing (or causing to be done) all things, in each case as are reasonably necessary, proper or advisable pursuant to applicable law or otherwise to consummate and make effective, as promptly as reasonably practicable, the Merger and the transactions contemplated by the Merger Agreement, including by using reasonable best efforts to (A) cause the conditions to the Merger precedent to the Closing to be satisfied and; (B)(I) obtain all consents, waivers, approvals, orders and authorizations from governmental authorities; and (II) make all registrations, declarations and filings with governmental authorities, in each case that are necessary or advisable to consummate the transactions contemplated by the Merger Agreement.

Each party will (and will cause their respective affiliates to, if applicable), (i) within 20 business days of entering into the Merger Agreement file with the FTC and the Antitrust Division of the Department of Justice a Notification and Report Form relating to the Merger Agreement and the Merger as required by the HSR Act; and (ii) within 15 business days of entering into the Merger Agreement, file such notification filings, forms and submissions, including any draft notifications in jurisdictions requiring pre-notification, with any governmental

authority as are required by other antitrust laws and any foreign investment laws in connection with the Merger. In relation to this, each party will make (or cause to be made), as promptly as reasonably practicable after consultation with the other parties, an appropriate response to a request for any additional information or documentary material from any governmental entity with respect to the Merger pursuant to the HSR Act or any other antitrust laws or any foreign investment laws applicable to the Merger.

If and to the extent necessary to obtain the necessary clearances, approvals, waivers, governmental approvals and to avoid or eliminate each and every impediment under any antitrust laws or foreign investment laws applicable to the Merger as promptly as reasonably practicable, Parent and Merger Sub shall use their reasonable best efforts to avoid or eliminate each and every impediment and to obtain all clearances, consents, approvals, waivers, actions, waiting period expirations or terminations, non-actions or other authorizations under the HSR Act, any other antitrust laws or any foreign investment laws, including offering, committing to, and effectuating (i) the sale, divestiture, transfer, license, disposition, or hold separate (through the establishment of a trust or otherwise), of any and all of the capital stock or other equity or voting interest, assets (whether tangible or intangible), rights, properties, products or businesses of Parent, Merger Sub, IAS or any of its subsidiaries; (ii) the termination, modification, or assignment of existing relationships, joint ventures, contracts, or obligations of Parent, Merger Sub, IAS or any of its subsidiaries; (iii) the modification of any course of conduct regarding future operations of Parent, Merger Sub, IAS or any of its subsidiaries; and (iv) any other restrictions on the activities of Parent, Merger Sub, IAS or any of its subsidiaries, including the freedom of action of Parent, Merger Sub, IAS or any of its subsidiaries with respect to, or their ability to retain, one or more of their respective operations, divisions, businesses, product lines, customers, assets or rights or interests, or their freedom of action with respect to the assets, properties, or businesses to be acquired pursuant to the Merger Agreement; in each case, so as to allow the consummation of the Merger as soon as reasonably practicable and, in any event, prior to the Termination Date.

Notwithstanding the foregoing, nothing in the Merger Agreement requires Parent, Merger Sub, IAS or any of its subsidiaries to (A) enter into any agreement or consent decree with the Department of Justice, FTC or any other governmental authority or take, or agree to take, any other action, in each case that is not conditioned on the Closing or (B) take any action outlined in items (i) through (iv) of the paragraph directly above, if such action, would (x) have, or would reasonably be expected to have, a material adverse effect on the business, results of operations or financial condition of IAS and its subsidiaries, taken as a whole or (y) otherwise involve any assets, properties, operations or businesses other than those of Parent, Merger Sub, IAS or its subsidiaries. Further, IAS and its subsidiaries will not take any action referred to in in items (i) through (iv) of the paragraph directly above without the prior written consent of Parent.

Notwithstanding anything contrary contained in the Merger Agreement, in no event will Parent or Merger Sub be obligated to take (or cause to be taken) any action referred to in in items (i) through (iv) of the paragraph two paragraphs above this paragraph with respect to or that involves Novacap or its affiliates or any investment funds or investment vehicles affiliated with, or managed or advised by, Novacap or its affiliates with respect to or that involves any portfolio company, any interest therein, or any investment of Novacap or its affiliates, other than with respect to Parent, Merger Sub, and IAS and its subsidiaries.

The Merger Agreement provides that IAS and its subsidiaries shall not, and shall not authorize or knowingly permit their respective representatives to, directly or indirectly, during the Interim Period:

During the Interim Period, IAS will be required to enforce, and will not be permitted to waive, terminate or modify, any provision of any standstill or similar provision that prohibits or purports to prohibit a proposal being made to the Company Board (or any committee thereof) unless the Company Board (or any committee thereof) determines in good faith, after consultation with its outside legal counsel, that the failure to take such action would be reasonably likely to be inconsistent with its fiduciary duties under applicable law.

IAS was required to promptly request that each person (other than Parent, Merger Sub, certain investment funds affiliated with Novacap party to the Limited Guarantee and the Lenders and their respective representatives) with whom a confidentiality agreement was entered into at any point during the 24-month period prior to the date of the Merger Agreement with respect to an Acquisition Proposal (as defined below) return or destroy all nonpublic information furnished by or on behalf of the Company or any of its subsidiaries and to promptly terminate access to all data rooms furnished in connection therewith.

The Merger Agreement provides that the term “Acquisition Proposal” means any written offer or proposal or indication of interest (other than an offer or proposal by Parent or Merger Sub) to engage in an Acquisition Transaction.

Furthermore, the term “Acquisition Transaction” means any single transaction or series of related transactions (other than the Merger) involving:

For the avoidance of doubt, the Merger and the other transactions contemplated by the Merger Agreement will not be deemed an Acquisition Proposal.

On September 24, 2025, the Company Board unanimously resolved to recommend that the stockholders of IAS adopt the Merger Agreement. On September 24, 2025, following the execution and delivery of the Merger Agreement, the Consenting Stockholders representing approximately 52.6% of the voting power of the outstanding shares of Company Common Stock as of such date, delivered the Written Consent to IAS (a copy of which was provided to Parent in accordance with the Merger Agreement), adopting the Merger Agreement in all

respects and approving the transactions contemplated thereby, including the Merger, in accordance with the DGCL and IAS’s Charter. As a result, no further action by IAS’s stockholders is required under applicable law, IAS’s Charter or the Merger Agreement to adopt the Merger Agreement or approve the Merger, and IAS will not be (i) soliciting your vote for the adoption of the Merger Agreement or approval of the Merger or (ii) calling a special meeting of IAS stockholders for purposes of voting on the adoption of the Merger Agreement or approval of the Merger.

IAS has agreed to use its reasonable best efforts to, and to cause its subsidiaries to use its reasonable best efforts to provide Parent with such customary cooperation as reasonably requested by Parent to arrange, syndicate and obtain any debt financing to fund the transactions contemplated by the Debt Commitment Letter including use reasonable best efforts in: (i) causing management of IAS to participate in a reasonable number of telephonic meetings, presentations, road shows, due diligence sessions, drafting sessions and sessions (upon reasonable request) with ratings agencies and other customary syndication activities at times and locations to be mutually agreed, (ii) providing reasonable and customary assistance to Parent with the preparation of customary marketing materials and providing reasonable cooperation with the due diligence efforts of financing sources, in each case, to the extent reasonable and customary for financings of the type of the Debt Financings, (iii) assisting Parent in connection with the preparation of any pledge and security documents and other definitive financing documents as may be reasonably requested by Parent and facilitating the pledging of, granting of a security interest in, and obtaining perfection of any liens on, collateral in connection with the Closing, (iv) obtaining the payoff letters, (v) providing, as promptly as reasonably practicable (and in any event, no less than four business days prior to the Closing date), all documentation and other information required by bank authorities under applicable “know your customer” and anti-money laundering rules and regulations, as reasonably requested of IAS or its subsidiaries in writing by Parent or the financing sources at least nine business days prior to the Closing date, (vi) assisting in the execution and delivery of definitive documents and closing certificates relating to the Debt Financing as may be reasonably requested by Parent, (vii) furnishing Parent as promptly as reasonably practicable, such other financial and other information in IAS’s possession, pertaining to IAS and its subsidiaries, as may be customarily required or reasonably requested by Parent for completion of the Debt Financing or similar financing and (viii) assisting in the taking of all corporate and other actions, subject to the occurrence of the Closing, reasonably required by Parent that are necessary to permit the consummation of the Debt Financing on the Closing date and to permit the proceeds thereof to be made available at the Closing.

No such requested cooperation from IAS or any of its subsidiaries will require it to (i) waive or amend any terms of the Merger Agreement or pay any fees or reimburse any expenses prior to the Effective Time, (ii) enter into any definitive agreement or documentation, the effectiveness of which is not conditioned upon the Closing, (iii) give any indemnities or incur any fees that are effective prior to the Effective Time or (iv) take any action that would unreasonably or materially interfere with the conduct of the business of IAS and its subsidiaries, breach any confidentiality obligations or create a risk of damage or destruction to any property or assets of IAS or any of its subsidiaries.

The Surviving Corporation and its subsidiaries will, and Parent will cause the Surviving Corporation and its subsidiaries to, honor and fulfill, in all respects, the obligations of IAS and its subsidiaries pursuant to any indemnification agreements set forth in the confidential disclosure letter, between IAS and any of its subsidiaries, on the one hand, and any of their respective current or former directors or officers, (and any person who becomes a director or officer of IAS or any of its subsidiaries prior to the Effective Time in accordance with the terms of the Merger Agreement), on the other hand (each, together with such person’s heirs, executors and administrators, an “Indemnified Person” and, collectively, the “Indemnified Persons”). In addition, for a period of six years following the Effective Time, the Surviving Corporation and its subsidiaries will, and Parent will cause the Surviving Corporation and its subsidiaries to, cause all the organizational documents of the Surviving Corporation and its subsidiaries to contain provisions with respect to indemnification, exculpation and the advancement of expenses that are at least as favorable as the indemnification, advancement and reimbursement of

expenses provisions set forth in the organizational documents of IAS and its subsidiaries that are in effect as of the date of the Merger Agreement, which provisions will not be repealed, amended or otherwise modified in any manner that would adversely affect the rights of the Indemnified Persons thereunder, except as required by applicable law.

For a period of six years following the Effective Time, the Surviving Corporation will, and Parent will cause the Surviving Corporation to, indemnify and hold harmless, to the fullest extent permitted by applicable law, and any of its subsidiaries as of the date of the Merger Agreement, shall indemnify and hold harmless each Indemnified Person from and against any costs, fees and expenses, including, to the extent applicable, reasonable and documented attorneys’ fees and investigation expenses, judgments, fines, penalties, losses, claims, damages, liabilities and amounts paid in settlement or compromise in connection with any legal proceeding, whether civil, criminal, administrative or investigative, whenever asserted, to the extent that such legal proceeding arises, directly or indirectly, out of or pertains, directly or indirectly, to the fact that an Indemnified Person is or was a director or officer of IAS or such subsidiary; any action or omission, or alleged action or omission, in such Indemnified Person’s capacity as a director or officer of IAS or any of its subsidiaries, or taken at the request of IAS or such subsidiary (including in connection with serving at the request of IAS or such subsidiary as a director, officer, employee, agent, trustee or fiduciary of another person (including any employee benefit plan)); or the Merger or other transactions contemplated by the Merger Agreement, as well as any actions taken by IAS, Parent or Merger Sub with respect to the Merger.

If, at any time prior to the sixth anniversary of the Effective Time, any Indemnified Person delivers to Parent a written notice asserting a claim for indemnification pursuant to the Merger Agreement terms described in the paragraph directly above, then the claim asserted in such notice will survive the sixth anniversary of the Effective Time until such claim is fully and finally resolved. The Surviving Corporation shall not be obligated to indemnify any Indemnified Person pursuant to the Merger Agreement terms described in the paragraph directly above for any settlement or compromise effected without the prior written consent of the Surviving Corporation (not to be unreasonably withheld, conditioned or delayed). In the event of any such legal proceeding, the Surviving Corporation will advance all reasonable and documented fees and expenses (including reasonable and documented fees and expenses of any outside counsel) as incurred by an Indemnified Person in the defense of such legal proceeding, subject to the Surviving Corporation’s receipt of an undertaking by or on behalf of such Indemnified Person to repay all amounts so advanced if it should ultimately be determined by final judicial decision from which there is no further right to appeal that such Indemnified Person is not entitled to be indemnified for such expenses. None of Parent, the Surviving Corporation nor any of their respective affiliates will settle or otherwise compromise or consent to the entry of any judgment with respect to, or otherwise seek the termination of, any legal proceeding for which indemnification may be sought by an Indemnified Person pursuant to the Merger Agreement unless such settlement, compromise, consent or termination includes an unconditional release of all Indemnified Persons from all liability arising out of, or relating to, such legal proceeding, or such Indemnified Person otherwise consents in writing (such consent not to be unreasonably withheld or delayed) to such settlement, compromise, consent or termination.

For a period of six years following the Effective Time, the Surviving Corporation shall (and Parent shall cause the Surviving Corporation to) maintain in effect IAS’s current directors’ and officers’ liability and errors and omissions liability insurance policy in respect of acts or omissions occurring at or prior to the Effective Time on terms (including with respect to coverage, conditions, retentions, limits and amounts) that are substantially equivalent to those of the director and officer insurance in effect as of the date of the Merger Agreement; provided that the Surviving Corporation will not be obligated to pay annual premiums in excess of 300% of the annual premium amount paid by IAS for coverage for its last full fiscal year ended prior to the Effective Time, which amount is referred to as the maximum annual premium. If the annual premiums of such insurance coverage exceed the maximum annual premium, then the Surviving Corporation shall obtain a policy with the greatest coverage available for a cost not exceeding the maximum annual premium from an insurance carrier with the same or better credit rating as IAS’s current directors’ and officers’ liability insurance carrier. In satisfaction of the foregoing obligations, prior to the Effective Time, IAS shall, in consultation with Parent, purchase a prepaid “tail” policy with respect to directors’ and officers’ liability insurance policies so long as the aggregate cost for such “tail” policy does not exceed the maximum annual premium. The Surviving Corporation shall (and Parent shall cause the Surviving Corporation to) maintain such “tail” policy in full force and effect for a period of no less than six years after the Effective Time and continue to honor its obligations under such “tail” policy.

Until the 12-month anniversary of the Closing (or, if earlier, until such time that an employee is no longer employed by Parent or its subsidiaries), the Surviving Corporation and its subsidiaries shall (and Parent shall cause the Surviving Corporation and its subsidiaries to) provide each continuing employee (i) a base salary or wage rate, as applicable, and target annual short-term cash incentive opportunities (excluding retention, long-term incentive, change in control or transaction compensation), in each case, that are no less favorable than that provided to such continuing employee immediately before the Effective Time; and (ii) other employee benefits (excluding severance, equity or equity-based compensation, long-term incentive, nonqualified deferred compensation benefits, defined benefit pension benefits or post-termination or retiree health or welfare benefits) that are substantially comparable in the aggregate to those provided to such continuing employee immediately before the Effective Time.

With respect to each benefit or compensation plan, program, policy, arrangement or agreement that is made available to any continuing employee at or after the Effective Time (each such plan, a “New Plan”), Parent and its affiliates (including the Surviving Corporation) shall (and Parent shall cause the Surviving Corporation and its affiliates to) cause to be granted to such continuing employee credit for such continuing employee’s length of service with IAS and its subsidiaries prior to the Effective Time, to the same extent such service was recognized under the analogous IAS employee benefit plans immediately prior to the Effective Time, for purposes of eligibility to participate, vesting and entitlement to benefits where length of service is relevant (including for purposes of vacation accrual), except that such service need not be recognized (i) to the extent that it would result in duplication of compensation or benefits for the same period of service, (ii) with respect to any qualified or nonqualified defined benefit plans, nonqualified deferred compensation, post-termination or retiree health or welfare benefits, or with respect to equity or equity-based compensation. In addition, and without limiting the generality of the foregoing, Parent shall use commercially reasonable efforts to cause, (i) each continuing employee to be immediately eligible to participate, without any waiting period, in any New Plan to the extent that coverage pursuant to such New Plan replaces coverage pursuant to analogous IAS employee benefit plans (such plans, the “Old Plans”); (ii) for purposes of each New Plan providing life insurance, medical, dental, pharmaceutical, vision or disability benefits, all waiting periods, pre-existing condition exclusions, evidence of insurability requirements and actively-at-work or similar requirements of such New Plan to be waived for the continuing employees and their covered dependents, to the extent such waiting periods, conditions and requirements were satisfied or would not apply under the analogous Old Plan; and (iii) for purposes of each New Plan providing medical, dental, pharmaceutical, or vision benefits, any eligible expenses incurred by the continuing employees and their covered dependents under the applicable Old Plans during the calendar year in which the participation under the New Plan begins, to be given credit under such New Plan for purposes of satisfying all deductible, coinsurance and maximum out-of-pocket requirements applicable to such continuing employees and their covered dependents as if such amounts had been paid in accordance with such New Plans. Any vacation or paid time off accrued but unused by a continuing employee as of immediately prior to the Effective Time will be credited to such continuing employee following the Effective Time, and will be made available to the continuing employees in accordance with the Company’s and its subsidiaries’ standard vacation and paid time off policies as in effect on the date of the Merger Agreement.

Except as otherwise set forth in the confidential disclosure schedule, with respect to IAS’s annual cash bonus programs (the “Company Bonus Program”), IAS and its subsidiaries shall pay to each continuing employee who participates in the Company Bonus Program and who remains employed with Parent, the Surviving Corporation or their respective subsidiaries through the applicable payment date, a bonus for the 2025 fiscal year (each, a “Annual Bonus”) on the date on which annual bonuses for the 2025 fiscal year would be paid in the ordinary course of business and subject to the terms of the Company Bonus Program. The amount of the Annual Bonus for each participant in the Company Bonus Plan (as defined in the Merger Agreement) shall be determined based on the greater of (i) actual performance through December 31, 2025 (as determined by the Company Board (or a committee thereof) in its sole discretion), and (ii) target performance.

The Merger Agreement contains other covenants and agreements, including a covenant in which each of Parent and IAS covenants or agrees to consult with each other before issuing, and give each other the opportunity to review and comment upon, any press release or other public statements with respect to the Merger, and shall not issue any such press release or make any such public statement without consulting with the other party, except as otherwise provided in the Merger Agreement.

In addition, IAS will, prior to the Effective Time:

The obligation of each party to consummate the Merger is subject to the satisfaction by each of the parties of the following conditions:

As of the date of this information statement, the Written Consent has been obtained by IAS and delivered to Parent in accordance with the terms of the Merger Agreement.

The obligations of Parent and Merger Sub to consummate the Merger are further subject to satisfaction (or waiver by Parent where permissible pursuant to applicable law) of the following further conditions:

The obligation of IAS to consummate the Merger is further subject to satisfaction (or waiver by IAS where permissible by applicable law) at or prior to the Effective Time of the following conditions:

The Merger Agreement may be terminated as follows:

The Merger Agreement also provided that (i) Parent could have terminated the Merger Agreement if the Written Consent was not delivered to Parent and IAS within 24 hours following the execution of the Merger Agreement; (ii) the Merger Agreement could have been terminated by Parent if at any time prior to IAS’s receipt of the Written Consent, the Company Board (or a committee thereof) had effected a Board Recommendation Change; provided Parent would have had to terminate the Merger Agreement within 10 business days after being notified in writing of a Board Recommendation Change; and (iii) IAS could have terminated the Merger Agreement at any time prior to IAS’s receipt of the Written Consent, in order to substantially concurrently enter into an Alternative Acquisition Agreement providing for a Superior Proposal, provided that IAS paid to Parent the Company Termination Fee; however, these termination provisions expired following delivery of the Written Consent on September 24, 2025.

IAS will pay Parent (or its designee) a termination fee of $52,500,000 (the “Company Termination Fee”) under the following circumstances:

Parent will pay IAS a termination fee of $100,000,000 (the “Parent Termination Fee”) in the event the Merger Agreement is terminated:

Notwithstanding the restrictions set forth above at any time prior to obtaining the Written Consent, which was obtained on September 24, 2025, IAS and the Company Board (or a committee thereof) could have, directly or indirectly, participated or engaged in discussions or negotiations with, furnished any nonpublic information relating to IAS or any of its subsidiaries to, or afforded access to the business, properties, assets, books, records or personnel of, IAS or any of its subsidiaries pursuant to an acceptable confidentiality agreement to any person that had made, renewed or delivered to IAS an Acquisition Proposal after the date of execution of the Merger Agreement and otherwise facilitated such Acquisition Proposal or assisted such person (and such person’s representatives and financing sources) with such Acquisition Proposal if requested by such person, in each case with respect to an Acquisition Proposal, and that the Company Board (or a committee thereof) had determined in good faith (after consultation with its financial advisors and outside legal counsel) either constituted a Superior Proposal or could reasonably be expected to lead to a Superior Proposal.

Except for the exceptions set forth below, which are no longer applicable, the Company Board will not (A) cause or permit IAS or any of its subsidiaries to enter into any letter of intent, memorandum of understanding, merger agreement, acquisition agreement or other contract to engage in an Acquisition Transaction, or (B) withhold, withdraw, amend or modify, or publicly propose to withhold, withdraw, amend or modify, the recommendation that the holders of Company Common Stock approve the adoption of the Merger Agreement in a manner adverse to Parent in any material respect or recommend to the IAS stockholders an Acquisition Proposal (a “Board Recommendation Change”).

Notwithstanding the restrictions set forth above at any time prior to obtaining the Written Consent, which was obtained on September 24, 2025, the Company Board (or a committee thereof) could have (i) made a Board Recommendation Change if the Company Board (or a committee thereof) had determined in good faith (after consultation with its outside legal counsel and financial advisor) that, as a result of a change, event, effect, development or circumstance (including any change in probability or magnitude of circumstances) that (a) is material to the Company and its subsidiaries, taken as a whole, (b) was not known or reasonably foreseeable to the Company Board on or prior to the date of the Merger Agreement (or, if known by the Company Board, the consequences of which were not known or reasonably foreseeable by the Company Board as of the date of the Merger Agreement) and (c) does not relate to any Acquisition Proposal, failure to make such Board Recommendation Change would be reasonably likely to be inconsistent with IAS’s directors’ fiduciary duties under applicable law or (ii) made a Board Recommendation Change or terminated the Merger Agreement if IAS received an unsolicited Acquisition Proposal, that the Company Board determined in good faith (after consultation with its outside legal counsel and financial advisor) constituted a Superior Proposal.

The parties to the Merger Agreement may amend the Merger Agreement by their written and signed agreement. However, after receipt of the Written Consent (which occurred on September 24, 2025) no amendment may be made to the Merger Agreement that requires the approval of IAS stockholders pursuant to the DGCL without such approval.

At any time prior to the Effective Time, Parent and IAS may, subject to the terms of the Merger Agreement and to the extent legally allowed (x) extend the time for performance of any of the obligations or other acts of the other party, as applicable; (y) waive any inaccuracies in the representations and warranties of the other party contained herein or in any document delivered pursuant hereto; and (z) subject to the requirements of applicable law, waive compliance by the other party with any of the Merger Agreements or conditions contained herein applicable to such party.

The Merger Agreement and all actions, proceedings, causes of action, claims or counterclaims (whether based on contract, tort, statute or otherwise) based upon, arising out of or relating to the Merger Agreement or the actions of Parent, Merger Sub or IAS in the negotiation, administration, performance and enforcement of the Merger Agreement (including any claim or cause of action based upon, arising out of or related to any representation or warranty made in connection with the Merger Agreement or as an inducement to enter into the Merger Agreement), shall be governed by, and construed in accordance with, the laws of the State of Delaware, including its statutes of limitations, without giving effect to any choice or conflict of laws provision or rule (whether of the State of Delaware or any other jurisdiction) that would cause the application of the laws, including any statutes of limitations, of any jurisdiction other than the State of Delaware.

Each party to the Merger Agreement has agreed to irrevocably submit to the exclusive general jurisdiction of the Court of Chancery of the State of Delaware and any state appellate court therefrom within the State of Delaware (or, if the Court of Chancery of the State of Delaware declines to accept jurisdiction over a particular matter, any other state or federal court within the State of Delaware), in the event that any dispute or controversy arises out of the Merger Agreement, the Limited Guarantee or the transactions thereby and has agreed that all claims with respect to such proceeding shall be brought, tried and determined only in such court. The parties to the Merger Agreement have agreed that a final judgment in any such proceeding will be conclusive and may be enforced in other jurisdictions by suit on the judgment or in any other manner provided by law.

Each party further irrevocably waived any and all right to trial by jury in any legal proceeding arising out of or related to the Merger Agreement or the transactions contemplated by the Merger Agreement.

IAS and Parent have acknowledged and agreed that (A) irreparable damage for which monetary damages, even if available, would not be an adequate remedy would occur in the event that the parties do not perform the provisions of the Merger Agreement; (B) the parties will be entitled, in addition to any other remedy to which they are entitled at law or in equity, to an injunction, specific performance and other equitable relief to prevent breaches of the Merger Agreement and to enforce specifically the terms and provisions of the Merger Agreement; and (C) the right of specific enforcement is an integral part of the Merger and without that right, neither IAS nor Parent would have entered into the Merger Agreement. The Merger Agreement further provides that notwithstanding the forgoing, IAS will only be entitled to seek specific performance if (i) all of the conditions to Parent and Merger Sub’s obligations to consummate the Merger (other than those conditions that by their terms are to be satisfied at the Closing, each of which is capable of being satisfied at the Closing); (ii) Parent and Merger Sub fail to consummate the Merger on the date they are required to do so pursuant to the Merger Agreement; (iii) all of the conditions to consummation of the Debt Financing provided by the Debt Commitment Letter have been satisfied (other than the receipt of the Equity Financing (as defined in the Merger Agreement) and the satisfaction of those conditions that by their terms are to be satisfied at the Closing, each of which is capable of being satisfied at the Closing) and the full amount of the Debt Financing has been funded or will be funded at the Closing in accordance with the terms of the Debt Commitment Letter if the Equity Financing were funded at the Closing; and (iv) IAS irrevocably confirms to Parent in writing that it is ready, willing and able to consummate the Closing and that all of the conditions to the Company’s obligation to consummate the Merger have been satisfied or waived.

The Company Common Stock began trading on the Nasdaq under the symbol “IAS” on June 30, 2021. Prior to that, there was no public market for the Company Common Stock. As of October 15, 2025, 167,854,529 shares of Company Common Stock were issued and outstanding, held by 12 stockholders of record.

Since the date of our initial public offering, IAS has not paid dividends on outstanding Company Common Stock. The terms of the Merger Agreement do not allow us to declare or pay a dividend between September 24, 2025, and the earlier of the consummation of the Merger or the termination of the Merger Agreement. Following the completion of the Merger, there will be no further market for the Company Common Stock.

Under the DGCL, you have the right to demand appraisal and to receive payment in cash for the fair value of your shares of Company Common Stock as determined by the Delaware Court of Chancery, together with interest, if any, as determined by the Delaware Court of Chancery, in lieu of the consideration you would otherwise be entitled to pursuant to the Merger Agreement, subject to the requirements and limitations set forth in Section 262 of the DGCL described herein. These rights are known as appraisal rights. Stockholders and beneficial owners electing to exercise appraisal rights must comply with the provisions of Section 262 of the DGCL in order to perfect their rights. Strict compliance with the statutory procedures is required to perfect appraisal rights under Delaware law.

This section is intended as a brief summary of the material provisions of Delaware law pertaining to appraisal rights. The following discussion, however, is not a complete summary of the law pertaining to appraisal rights under the DGCL and is qualified in its entirety by the full text of Section 262 of the DGCL, which is accessible at the following publicly available website: https://delcode.delaware.gov/title8/c001/sc09/index.html#262. All references in Section 262 of the DGCL and in this summary to “stockholder” (and all references in this summary to “holder”) are to the record holder of the shares of Company Common Stock immediately prior to the Effective Time as to which appraisal rights are asserted. All references within Section 262 of the DGCL and this summary to “beneficial owner” mean the beneficial owner of shares of Company Common Stock held either in voting trust or by a nominee on behalf of such person. Failure to comply strictly with the procedures set forth in Section 262 of the DGCL will result in the loss of appraisal rights. The following discussion does not constitute any legal or other advice, nor does it constitute a recommendation as to whether or not an IAS stockholder or beneficial owner should exercise its right to seek appraisal under Section 262 of the DGCL. In view of the complexity of the provisions of Section 262 of the DGCL, stockholders and beneficial owners wishing to exercise appraisal rights are urged to consult their legal and financial advisors before attempting to exercise such rights.

If the Merger is consummated, subject to certain exceptions specified in Section 262 of the DGCL and summarized below, holders and beneficial owners of shares of Company Common Stock who: (a) submit a proper written demand for appraisal of such shares to IAS; (b) hold or beneficially own such shares on the date of the making of such demand and continuously remain the record holders or beneficial owners, as the case may be, of such shares through the Effective Time; (c) otherwise comply with the applicable procedures and requirements set forth in Section 262 of the DGCL; and (d) do not thereafter withdraw his, her or its demand for appraisal of such shares will be entitled to have their shares appraised by the Delaware Court of Chancery and receive payment in cash of the “fair value” of such shares (as determined by the Delaware Court of Chancery, exclusive of any element of value arising from the accomplishment or expectation of the Merger) as of the completion of the Merger, instead of the Per Share Price. Any such IAS stockholder or beneficial owner awarded “fair value” for the holder’s shares by the court would receive payment of that fair value in cash, together with interest, if any, in lieu of the right to receive the Per Share Price. It is possible that any such “fair value” as determined by the Delaware Court of Chancery may be more or less than, or the same as, that which IAS stockholders will receive pursuant to the Merger Agreement.

When a merger agreement is approved by written consent without a meeting pursuant to Section 228 of the DGCL, as is the case with the Merger Agreement, Section 262 requires that either a constituent corporation before, or the Surviving Corporation within 10 days after, the Effective Time of the merger notify each of its stockholders who is entitled to appraisal rights that appraisal rights are so available and must include in each such notice a copy of Section 262 of the DGCL or information directing the stockholders to a publicly available electronic resource at which Section 262 of the DGCL may be accessed without subscription or cost. Such notice, if given on or after the Effective Time of the merger, must also notify the stockholders of the Effective Time of the merger.

This information statement constitutes our notice to IAS’s stockholders of the availability of appraisal rights in connection with the Merger in compliance with the requirements of Section 262 of the DGCL, and a copy of the applicable statutory provisions is accessible at the following publicly available website without subscription or cost: https://delcode.delaware.gov/title8/c001/sc09/index.html#262.

Stockholders or beneficial owners who wish to exercise appraisal rights or who wish to preserve the right to do so should review the following summary and the applicable statutory provisions carefully. Failure to comply with the procedures of Section 262 of the DGCL in a timely and proper manner will result in the loss of appraisal rights. In addition, the Delaware Court of Chancery will dismiss appraisal proceedings in respect of IAS unless certain stock ownership conditions are satisfied by the IAS stockholders and beneficial owners seeking appraisal. Because of the complexity of the procedures for exercising the right to seek appraisal, stockholders and beneficial owners who wish to exercise appraisal rights are urged to consult with their own legal and financial advisors in connection with compliance under Section 262 of the DGCL. An IAS stockholder who loses his, her, their or its appraisal rights will be entitled to receive the Per Share Price pursuant to and in accordance with the Merger Agreement.

If you are an IAS stockholder or beneficial owner and wish to exercise the right to seek an appraisal of your shares of Company Common Stock, you must satisfy each of the following conditions:

If you fail to comply with any of these conditions and the Merger is completed, you will be entitled to receive the Per Share Price pursuant to the terms of the Merger Agreement, but you will have no appraisal rights with respect to your shares of Company Common Stock.

In addition, because the Company Common Stock is listed on a national securities exchange and is expected to continue to be listed on such exchange immediately prior to the consummation of the Merger, the Delaware Court of Chancery will dismiss appraisal proceedings as to all holders and beneficial owners of shares of Company Common Stock who are otherwise entitled to appraisal rights, unless (a) the total number of shares entitled to appraisal exceeds 1% of the outstanding shares of Company Common Stock eligible for appraisal or (b) the value of the consideration provided in the Merger for such total number of shares entitled to appraisal exceeds $1 million. We refer to conditions (a) and (b) as the “ownership thresholds.” At least one of the ownership thresholds must be met in order for IAS stockholders to be entitled to seek appraisal with respect to such shares of Company Common Stock.

A demand for appraisal must be executed by or on behalf of the stockholder of record or beneficial owner of the shares. The demand should set forth, fully and correctly, the name of the stockholder holding the shares in record name as it appears on the stock certificates (or in the stock ledger). The demand must reasonably inform IAS of the identity of the record holder, or beneficial owner, as applicable, holding the shares for which appraisal is demanded and that the stockholder or beneficial owner intends to demand appraisal of his, her or its shares of Company Common Stock. In addition, if a demand is made by a beneficial owner, the demand must (a) reasonably identify the holder of record of the shares for which the demand is made, (b) provide documentary evidence of such beneficial owner’s beneficial ownership and a statement that such documentary evidence is a true and correct copy of what it purports to be and (c) provide an address at which such beneficial owner consents to receive notices given by the Surviving Corporation and the office of Register in Chancery and to be set forth on the verified list required by Section 262(f) of the DGCL. A holder of record, such as a bank, broker or other nominee, who holds shares of Company Common Stock as a nominee or intermediary for others, may exercise his, her or its right of appraisal with respect to the shares of Company Common Stock held for one or more beneficial owners, while not exercising this right for other beneficial owners. In that case, the written demand should state the number of shares of Company Common Stock as to which appraisal is sought. Where no number of shares of Company Common Stock is expressly mentioned, the demand will be presumed to cover all shares of Company Common Stock held in the name of the holder of record or beneficially owned by the beneficial owner.

If you own shares of Company Common Stock jointly with one or more other persons, as in a joint tenancy or tenancy in common, the demand for appraisal should be executed by or for you and all other joint owners. An authorized agent, including an agent for two or more joint owners, may execute the demand for appraisal for a stockholder of record; however, the agent must identify the holder or holders of record and expressly disclose the fact that, in exercising the demand, such person is acting as an agent.

If you elect to exercise appraisal rights under Section 262 of the DGCL, you should mail or deliver a written demand to:

If the Merger is consummated, the Surviving Corporation will give written notice of the Effective Time within 10 days after the Effective Time to all of the IAS stockholders and beneficial owners that are entitled to appraisal rights; provided, however, that if such notice is sent more than 20 days following the sending of this information statement, such notice need only be sent to each holder and beneficial owner who is entitled to appraisal rights and who has demanded appraisal of his, her or its shares of Company Common Stock in accordance with Section 262 of the DGCL. At any time within sixty days after the Effective Time, any person entitled to appraisal rights who did not commence an appraisal proceeding or join in such a proceeding as a named party will have the right to withdraw such person’s demand and to accept the Per Share Price in accordance with the Merger Agreement for his, her or its shares of Company Common Stock. In addition, no appraisal proceeding in the Delaware Court of Chancery will be dismissed as to any stockholder or beneficial owner without the approval of the Delaware Court of Chancery, which approval may be conditioned on the terms the Delaware Court of Chancery deems just (including, without limitation, a reservation of jurisdiction for any application to the Delaware Court of Chancery made with respect to the allocation of the expenses of the proceeding); provided, however, that this will not affect the right of any IAS stockholder or beneficial owner that has made an appraisal demand but who has not commenced an appraisal proceeding or joined such proceeding as a named party to withdraw such stockholder’s or beneficial owner’s demand for appraisal and to accept the terms and the Per Share Price offered in the Merger within sixty days after the Effective Time. Within 120 days after the Effective Time, either a record holder or a beneficial owner of Company Common Stock, provided such person has complied with the requirements of Section 262 of the DGCL and is otherwise entitled to appraisal rights, or the Surviving Corporation may commence an appraisal proceeding by filing a petition in the Delaware Court of Chancery, with a copy served on the Surviving Corporation in the case of a petition filed by a

stockholder or beneficial owner, demanding an appraisal of the fair value of the shares of Company Common Stock held by all persons who have properly demanded appraisal. The Surviving Corporation is under no obligation to file an appraisal petition and has no present intention of doing so. If you desire to have your shares appraised, you should initiate any petitions necessary for the perfection of your appraisal rights within the time periods and in the manner prescribed in Section 262 of the DGCL. If, within 120 days after the Effective Time, no petition has been filed as provided in Section 262 of the DGCL, all rights to appraisal will cease and any person who previously demanded appraisal will become entitled only to the Per Share Price, in accordance with and pursuant to the terms of the Merger Agreement.

Within 120 days after the Effective Time, any stockholder or beneficial owner who has complied with the provisions of Section 262 of the DGCL will be entitled to receive from the Surviving Corporation, upon written request, a statement setting forth the aggregate number of shares of Company Common Stock with respect to which IAS has received demands for appraisal, and the aggregate number of holders or beneficial owners holding or owning those shares (for which purpose the record holder of shares held by a beneficial owner who has made a demand for appraisal shall not be considered a separate stockholder holding such shares). The Surviving Corporation must give this statement to you within the later of (a) 10 days after receipt by the Surviving Corporation of the request therefor or (b) 10 days after expiration of the period for delivery of demands for appraisal.

If a petition for appraisal is duly filed by you or another holder of record or beneficial owner of Company Common Stock who has properly exercised his, her or its appraisal rights in accordance with the provisions of Section 262 of the DGCL, and a copy of the petition is delivered to the Surviving Corporation, the Surviving Corporation will then be obligated, within 20 days after receiving service of a copy of the petition, to file in the Office of the Register in Chancery in which the petition was filed a duly verified list containing the names and addresses of all holders and beneficial owners who have demanded appraisal of their shares and with whom agreements as to the value of their shares have not been reached by the Surviving Corporation. Upon the filing of any such petition, the Delaware Court of Chancery may order that notice of the time and place fixed for the hearing on the petition be mailed, by registered or certified mail, to the Surviving Corporation and all persons shown on the verified list at the addresses stated therein. The costs of these notices are borne by the Surviving Corporation. After notice to persons who demanded appraisal of their shares of Company Common Stock as may be required by the court, the Delaware Court of Chancery is empowered to conduct a hearing on the petition to determine those persons who have complied with Section 262 and who have become entitled to appraisal thereunder. The Delaware Court of Chancery will then determine which stockholders and beneficial owners are entitled to appraisal rights and may require the persons demanding appraisal for their shares represented by certificates to submit their stock certificates to the Register in Chancery for notation thereon of the pendency of the appraisal proceedings, and the Delaware Court of Chancery may dismiss the proceedings as to any such person who fails to comply with this direction. The Delaware Court of Chancery will also dismiss proceedings as to all IAS stockholders and beneficial owners if neither of the ownership thresholds described above is met. Where proceedings are not dismissed or the demand for appraisal is not successfully withdrawn, the appraisal proceeding will be conducted as to the shares of Company Common Stock for which the applicable stockholders and beneficial owners thereof are entitled to appraisal, in accordance with the rules of the Delaware Court of Chancery, including any rules specifically governing appraisal proceedings. The Delaware Court of Chancery will thereafter determine the fair value of such shares of Company Common Stock at the Effective Time, exclusive of any element of value arising from the accomplishment or expectation of the Merger, together with interest, if any, to be paid upon the amount determined to be fair value. Unless the Delaware Court of Chancery in its discretion determines otherwise for good cause shown, interest from the Effective Time through the date of payment of the judgment will be compounded quarterly and will accrue at 5% over the Federal Reserve discount rate (including any surcharge) as established from time to time during the period between the Effective Time and the date of payment of the judgment. However, the Surviving Corporation has the right, at any point prior to the Delaware Court of Chancery’s entry of judgment in the proceedings, to make a voluntary cash payment to each person entitled to appraisal. Notwithstanding the foregoing or anything herein to the contrary, if the Surviving Corporation makes a voluntary cash payment at any time before the entry of judgment in the appraisal proceeding pursuant to subsection (h) of Section 262 of the DGCL, interest will accrue thereafter only on the sum of (a) the difference, if any, between the amount paid by the Surviving Corporation in such voluntary cash payment and the fair value of the shares as determined by the Delaware Court of Chancery and (b) interest accrued on the amount of the voluntary cash payment before such payment was made, unless such interest was

paid at the time the voluntary cash payment is made. Upon application by the Surviving Corporation or by any person entitled to participate in the appraisal proceeding, the Delaware Court of Chancery may, in its discretion, proceed to trial upon the appraisal prior to the final determination of the persons entitled to an appraisal. Any person whose name appears on the verified list may participate fully in all proceedings until it is finally determined that such person is not entitled to appraisal rights. When the value is determined, the Delaware Court of Chancery will direct the payment of such value, less any amounts already paid in a voluntary cash payment, with interest thereon, if any, to the persons entitled to receive the same. Payment shall be so made to each such person upon such terms and conditions as the Delaware Court of Chancery may order.

In determining the fair value, the Delaware Court of Chancery is required to take into account all relevant factors. In Weinberger v. UOP, Inc., the Delaware Supreme Court discussed the factors that could be considered in determining fair value in an appraisal proceeding, stating that “proof of value by any techniques or methods which are generally considered acceptable in the financial community and otherwise admissible in court” should be considered and that “[f]air price obviously requires consideration of all relevant factors involving the value of a company.”

The Delaware Supreme Court has stated that, in making this determination of fair value, the court must consider market value, asset value, dividends, earnings prospects, the nature of the enterprise and any other factors which were known, or which could be ascertained as of the date of the Merger which throw any light on future prospects of the merged corporation. The Delaware Supreme Court has recently indicated that transaction price is one of the relevant factors the Delaware Court of Chancery may consider in determining fair value, and that absent deficiencies in the sale process the transaction price may be given “considerable weight.” Section 262 of the DGCL provides that fair value is to be “exclusive of any element of value arising from the accomplishment or expectation of the merger.” In Cede & Co. v. Technicolor, Inc., the Delaware Supreme Court stated that such exclusion is a “narrow exclusion [that] does not encompass known elements of value,” but which rather applies only to the speculative elements of value arising from such accomplishment or expectation. In Weinberger, the Delaware Supreme Court construed Section 262 of the DGCL to mean that “elements of future value, including the nature of the enterprise, which are known or susceptible of proof as of the date of the merger and not the product of speculation, may be considered.”

You should be aware that the fair value of your shares of Company Common Stock as determined under Section 262 of the DGCL could be more than, the same as, or less than the value that you are entitled to receive under the terms of the Merger Agreement and that an opinion of an investment banking firm as to the fairness from a financial point of view of the consideration payable in a merger is not an opinion as to, and does not in any manner address, fair value under Section 262 of the DGCL.

Moreover, neither IAS nor Parent anticipates offering more than the Per Share Price to any IAS stockholder or beneficial owner exercising appraisal rights and reserves the right to make a voluntary cash payment pursuant to subsection (h) of Section 262 of the DGCL and to assert, in any appraisal proceeding, that, for purposes of Section 262, the “fair value” of a share of Company Common Stock is less than the Per Share Price. No representation is made as to the outcome of the appraisal of fair value as determined by the Delaware Court of Chancery.

If no party files a petition for appraisal within 120 days after the Effective Time or if neither of the ownership thresholds above has been satisfied in respect of such shares, then all IAS stockholders and beneficial owners will lose the right to an appraisal and will instead receive the Per Share Price described in the Merger Agreement, in accordance with and pursuant to the terms thereof.

The Delaware Court of Chancery may determine the costs of the appraisal proceeding and may tax those costs to the parties as the Delaware Court of Chancery determines to be equitable under the circumstances. Upon application of any person whose name appears on the verified list filed by the Surviving Corporation who participated in the proceeding and incurred expenses in connection therewith, the Delaware Court of Chancery may order all or a portion of such expenses, including, without limitation, reasonable attorneys’ fees and the fees and expenses of experts, to be charged pro rata against the value of all shares of Company Common Stock entitled to appraisal not dismissed pursuant to Section 262(k) of the DGCL or subject to such an award pursuant to a reservation of jurisdiction under Section 262(k) of the DGCL. In the absence of such an order, each party to the appraisal proceeding bears its own expenses of its attorneys and experts.

If you have duly demanded appraisal in compliance with Section 262 of the DGCL you may not, on or after the Effective Time, vote the shares subject to the demand for any purpose or receive any dividends or other distributions on those shares, except dividends or other distributions payable to holders of record of Company Common Stock as of a record date prior to the Effective Time.

If a person who has made a demand for an appraisal in accordance with Section 262 shall deliver to the Surviving Corporation a written withdrawal of such person’s demand for an appraisal in respect of some or all of such person’s shares of Company Common Stock in accordance with subsection (e) of Section 262, either within sixty days after the Effective Time or thereafter with the written approval of the Surviving Corporation, then the right of such person to an appraisal of such shares subject to the withdrawal will cease. Notwithstanding the foregoing, an appraisal proceeding in the Delaware Court of Chancery shall not be dismissed as to any person without the approval of the Delaware Court of Chancery, and such approval may be conditioned upon such terms as the Delaware Court of Chancery deems just, including, without limitation, a reservation of jurisdiction for any application to the Delaware Court of Chancery made under subsection (j) of Section 262; provided, however, that any person who has not commenced an appraisal proceeding or joined such proceeding as a named party may withdraw such person’s demand for appraisal and to accept the terms and the Per Share Price offered in the Merger within sixty days after the Effective Time. If you fail to perfect, successfully withdraw your demand for appraisal, or lose the appraisal right, your shares of Company Common Stock will be converted into the right to receive the Per Share Price, in accordance with and pursuant to the Merger Agreement, without interest thereon.

Failure to follow the steps required by Section 262 of the DGCL for perfecting appraisal rights will result in the loss of your appraisal rights. In that event, you will be entitled to receive the Per Share Price for your shares of Company Common Stock in accordance with the Merger Agreement without interest. In view of the complexity of the provisions of Section 262 of the DGCL, if you are an IAS stockholder or beneficial owner and are considering exercising your appraisal rights under the DGCL, you are urged to consult your own legal and financial advisor.

Holders and beneficial owners of Company Common Stock considering seeking to exercise their appraisal rights should be aware that the fair value of their shares of Company Common Stock as determined under Section 262 could be more than, the same as or less than the consideration they would receive pursuant to the Merger if they did not seek appraisal of their shares of Company Common Stock. Failure to comply strictly with all of the procedures set forth in Section 262 will result in a loss of statutory appraisal rights. The process of demanding and exercising appraisal rights requires compliance with the prerequisites of Section 262 of the DGCL.

Consequently, and in view of the complexity of the provisions of Section 262, if you wish to exercise your appraisal rights, you are urged to consult with your own legal and financial advisors in connection with compliance under Section 262 of the DGCL. To the extent there are any inconsistencies between the foregoing summary and Section 262 of the DGCL, the DGCL will govern.

The following table sets forth information about the beneficial ownership of the Company Common Stock as of October 15, 2025, for:

The numbers of shares of Company Common Stock beneficially owned and percentages of beneficial ownership are based on 167,854,529 shares of Company Common Stock outstanding as of October 15, 2025.

Beneficial ownership for the purposes of the following table is determined in accordance with the rules and regulations of the SEC. These rules generally provide that a person is the beneficial owner of securities if such person has or shares the power to vote or direct the voting thereof, or to dispose or direct the disposition thereof or has the right to acquire such powers within 60 days. Company Common Stock subject to Company Options or Company RSUs that are currently exercisable or that will be exercisable or will vest within 60 days of October 15, 2025, are deemed to be outstanding and beneficially owned by the person holding the Company Options or Company RSUs. These shares, however, are not deemed outstanding for the purposes of computing the percentage ownership of any other person. Except as disclosed in the footnotes to this table and subject to applicable community property laws, we believe that each stockholder identified in the table possesses sole voting and investment power over all shares of Company Common Stock shown as beneficially owned by the stockholder.

Unless otherwise noted below, the mailing address of each beneficial owner listed on the table is c/o Integral Ad Science Holding Corp., 12 East 49th Street, 20th Floor, New York, NY 10017.

The SEC’s rules permit us and intermediaries such as brokers to satisfy delivery requirements for information statements with respect to two or more stockholders sharing the same address by delivering a single information statement addressed to those stockholders, unless we received contrary instructions from the impacted stockholder. We agree to deliver promptly, upon written or oral request, a separate copy of this information statement, as requested, to any stockholder at an address to which a single copy of this information statement was delivered. If you prefer to receive separate copies of the information statement, contact Broadridge Financial Solutions, Inc. at 1-866-540-7095 or in writing at Broadridge, Householding Department, 51 Mercedes Way, Edgewood, New York 11717. A number of brokerage firms have instituted householding. They will have their own procedures for stockholders who wish to receive individual copies of this information statement.

We file annual, quarterly and current reports, proxy statements and other documents with the SEC. These reports contain additional information about IAS. IAS’s filings with the SEC are available to the public free of charge on the SEC’s website at www.sec.gov. Those filings are also accessible to the public for free through the “Financials—SEC Filings” section of IAS’s investor relations website at investors.integralads.com. Our website address is being provided as an inactive textual reference only. The information provided on or accessible through our corporate website is not incorporated by reference into and is not part of this information statement.

The SEC allows IAS to “incorporate by reference” information that it files with the SEC in other documents into this information statement. This means that IAS may disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this information statement. This information statement and the information that IAS files later with the SEC may update and supersede the information incorporated by reference. Such updated and superseded information will not, except as so modified or superseded, constitute part of this information statement.

IAS incorporates by reference in this information statement each document it files under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of the initial filing of this information statement and before the Effective Time, other than Current Reports on Form 8-K furnished pursuant to Item 2.02 or Item 7.01 of Form 8-K, including any exhibits included with such information, unless otherwise indicated therein. IAS also incorporates by reference in this information statement the following documents filed by it with the SEC under the Exchange Act:

Information furnished under Item 2.02 or Item 7.01 of any Current Report on Form 8-K, including related exhibits, is not and will not be incorporated by reference into this information statement, unless expressly stated otherwise therein.

IAS undertakes to provide without charge to each person to whom a copy of this information statement has been delivered, upon written or oral request, by first class mail or other equally prompt means within one business day of receipt of such request, a copy of any or all of the documents incorporated by reference in this information statement, other than the exhibits to these documents, unless the exhibits are specifically incorporated by reference into the information that this information statement incorporates. You may request a copy of these filings by writing to us at:

Parent and Merger Sub have supplied, and IAS has not independently verified, the information in this information statement relating to Parent and Merger Sub.

Stockholders should not rely on information that purports to be made by or on behalf of IAS other than that contained in or incorporated by reference in this information statement. IAS has not authorized anyone to provide information on behalf of IAS that is different from that contained in this information statement. This information statement is dated November 7, 2025. No assumption should be made that the information contained in this information statement is accurate as of any date other than that date, and the mailing of this information statement will not create any implication to the contrary.