PRESS RELEASE

CSG Systems INTERNATIONAL reports

THIRD Quarter 2025 RESULTS

DENVER--(November 5, 2025) — CSG® (NASDAQ: CSGS) today reported results for the quarter ended September 30, 2025.

Financial Results:

Third quarter 2025 financial results:

Shareholder Returns:

Financial Overview (unaudited)

(in thousands, except per share amounts and percentages):

For additional information and reconciliations regarding CSG’s use of non-GAAP financial measures, please refer to the attached Exhibit 2 and the Investor Relations section of CSG’s website at csgi.com.

Results of Operations

GAAP Results: Total revenue for the third quarter of 2025 was $303.6 million, a 2.9% increase when compared to revenue of $295.1 million for the third quarter of 2024. The increase in revenue can be mainly attributed to the continued growth of CSG’s SaaS and related solutions.

GAAP operating income for the third quarter of 2025 was $30.5 million, or 10.0% of total revenue, compared to $31.8 million, or 10.8% of total revenue, for the third quarter of 2024.

GAAP EPS for the third quarter of 2025 was $0.73, compared to $0.67 for the third quarter of 2024, with the increase mainly attributed to foreign currency movements.

Non-GAAP Results: Non-GAAP operating income for the third quarter of 2025 was $54.5 million, or a non-GAAP adjusted operating margin of 19.5%, compared to $50.1 million, or a non-GAAP adjusted operating margin of 18.4% for the third quarter of 2024. The increase in non-GAAP operating margin can be mainly attributed to the cost efficiency actions discussed above.

Non-GAAP EPS for the third quarter of 2025 was $1.31, compared to $1.06 for the third quarter of 2024. The increase in non-GAAP EPS is mainly due the higher non-GAAP operating income, discussed above, and foreign currency movements.

Balance Sheet and Cash Flows

Cash and cash equivalents as of September 30, 2025 were $158.4 million compared to $145.9 million as of June 30, 2025 and $161.8 million as of December 31, 2024. CSG had net cash flows provided by operations for the third quarters ended September 30, 2025 and 2024 of $47.9 million and $39.5 million, respectively, and had non-GAAP adjusted free cash flow of $43.9 million and $32.0 million, respectively.

Additional Information

For information about CSG, please visit CSG’s website at csgi.com. Additional information can be found in the Investor Relations section of the website.

About CSG

CSG empowers companies to build unforgettable experiences, making it easier for people and businesses to connect with, use and pay for the services they value most. Our customer experience, billing and payments solutions help companies of any size make money and make a difference. With our SaaS solutions, company leaders can take control of their future and tap into guidance along the way from our fiercely committed and forward-thinking CSGers around the world.

Want to be future-ready and a change-maker like the global brands that trust CSG? Visit csgi.com to learn more.

Forward-Looking Statements

This news release contains forward-looking statements as defined under the Securities Act of 1933, as amended, that are based on assumptions about a number of important factors and involve risks and uncertainties that could cause actual results to differ materially from what appears in this news release. Some of these key factors include, but are not limited to the following items:

• CSG derives a significant portion of its revenue from a limited number of customers, with approximately forty percent of its revenue from its two largest customers;

• Fluctuations in credit market conditions, general global economic and political conditions, and foreign currency exchange rates;

• CSG’s ability to maintain a reliable, secure computing environment;

• Continued market acceptance of CSG’s products and services;

• CSG’s ability to continuously develop and enhance products in a timely, cost-effective, technically advanced and competitive manner;

• CSG’s ability to deliver its solutions in a timely fashion within budget, particularly large and complex software implementations;

• CSG’s dependency on the global telecommunications industry, and in particular, the North American telecommunications industry;

• CSG’s ability to meet its financial expectations;

• Increasing competition in CSG’s market from companies of greater size and with broader presence;

• CSG’s ability to successfully integrate and manage acquired businesses or assets to achieve expected strategic, operating and financial goals;

• CSG’s ability to protect its intellectual property rights;

• CSG’s ability to conduct business in the international marketplace;

• CSG’s ability to comply with applicable U.S. and International laws and regulations;

• CSG’s business may be disrupted, and its results of operations and cash flows adversely affected by a global pandemic; and

This list is not exhaustive, and readers are encouraged to review the additional risks and important factors described in CSG’s reports on Forms 10-K and 10-Q and other filings made with the SEC.

For more information, contact:

John Rea, SVP, Head of Finance, Treasury, Investor Relations, and ESG Reporting

(210) 687-4409

E-mail: John.Rea@csgi.com

Kyle Fisher, Senior Manager, Treasury and Investor Relations

(303) 796-2851

E-mail: Kyle.Fisher@csgi.com

CSG SYSTEMS INTERNATIONAL, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS-UNAUDITED

(in thousands)

CSG SYSTEMS INTERNATIONAL, INC.

CONDENSED CONSOLIDATED STATEMENTS OF INCOME-UNAUDITED

(in thousands, except per share amounts)

CSG SYSTEMS INTERNATIONAL, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS-UNAUDITED

(in thousands)

EXHIBIT 1

CSG SYSTEMS INTERNATIONAL, INC.

SUPPLEMENTAL REVENUE ANALYSIS

Revenue by Significant Customers: 10% or more of Revenue

Revenue by Vertical

Revenue by Geography

EXHIBIT 2

CSG SYSTEMS INTERNATIONAL, INC.

DISCLOSURES FOR NON-GAAP FINANCIAL MEASURES

Use of Non-GAAP Financial Measures and Limitations

To supplement its condensed consolidated financial statements presented in accordance with generally accepted accounting principles (GAAP), CSG uses non-GAAP operating income, non-GAAP adjusted operating margin percentage, non-GAAP EPS, non-GAAP adjusted EBITDA, and non-GAAP adjusted free cash flow. CSG believes that these non-GAAP financial measures, when reviewed in conjunction with its GAAP financial measures, provide investors with greater transparency to the information used by CSG’s management in its financial and operational decision making. CSG uses these non-GAAP financial measures for the following purposes:

• Certain internal financial planning, reporting, and analysis;

• Forecasting and budgeting;

• Certain management compensation incentives; and

• Communications with CSG’s Board of Directors, stockholders, financial analysts, and investors.

These non-GAAP financial measures are provided with the intent of providing investors with the following information:

• A more complete understanding of CSG’s underlying operational results, trends, and cash generating capabilities;

• Consistency and comparability with CSG’s historical financial results; and

• Comparability to similar companies, many of which present similar non-GAAP financial measures to investors.

Non-GAAP financial measures are not measures of performance under GAAP, and therefore should not be considered in isolation or as a substitute for GAAP financial information. Limitations with the use of non-GAAP financial measures include the following items:

• Non-GAAP financial measures are not based on any comprehensive set of accounting rules or principles;

• The way in which CSG calculates non-GAAP financial measures may differ from the way in which other companies calculate similar non-GAAP financial measures;

• Non-GAAP financial measures do not include all items of income and expense that affect CSG’s operations and that are required by GAAP to be included in financial statements;

• Certain adjustments to CSG’s non-GAAP financial measures result in the exclusion of items that are recurring and will be reflected in CSG’s financial statements in future periods; and

• Certain charges excluded from CSG’s non-GAAP financial measures are cash expenses, and therefore do impact CSG’s cash position.

CSG compensates for these limitations by relying primarily on its GAAP results and using non-GAAP financial measures as a supplement only. Additionally, CSG provides specific information regarding the treatment of GAAP amounts considered in preparing the non-GAAP financial measures and reconciles each non-GAAP financial measure to the most directly comparable GAAP measure.

Non-GAAP Financial Measures: Basis of Presentation

The table below outlines the exclusions from CSG’s non-GAAP financial measures:

CSG believes that excluding certain items in calculating its non-GAAP financial measures provides meaningful supplemental information regarding CSG’s performance and these items are excluded for the following reasons:

• Acquisition-related expenses include amortization of acquired intangible assets, earn-out compensation, and transaction-related costs. Transaction-related costs, which typically include expenses related to legal, accounting, and other professional services, are direct and incremental expenses related to business acquisitions, and thus, are not considered reflective of CSG’s recurring business operating results. The total amount of acquisition-related expenses can vary significantly between periods based on the number and size of acquisition activities, previously acquired intangible assets becoming fully amortized, and ultimate realization of earn-out compensation. In addition, the timing of these expenses may not directly correlate with underlying performance of the CSG’s operations. Therefore, the exclusion of acquisition-related expenses in calculating CSG’s non-GAAP financial measures allows management and investors an additional means to compare CSG’s current financial results with historical and future periods.

• Stock-based compensation results from CSG’s issuance of equity awards to its employees under incentive compensation programs. The amount of this incentive compensation in any period is not generally linked to the level of performance by employees or CSG. The exclusion of these expenses in calculating CSG’s non-GAAP financial measures allows management and investors an additional means to evaluate the non-cash expense related to compensation included in CSG’s results of operations, and therefore, the exclusion of this item allows investors to further evaluate the cash generating capabilities of CSG’s business.

CSG also reports non-GAAP adjusted EBITDA and non-GAAP adjusted free cash flow. Management believes non-GAAP adjusted EBITDA is a useful measure to investors in evaluating CSG’s operating performance, debt servicing capabilities, and enterprise valuation. CSG defines non-GAAP adjusted EBITDA as income before interest, income taxes, depreciation, amortization, stock-based compensation, foreign currency transaction adjustments, acquisition-related expenses, and unusual items, such as restructuring and reorganization charges, executive transition costs, gains and losses related to the extinguishment of debt, and gains and losses on acquisitions or dispositions, as discussed above. Additionally, management uses non-GAAP adjusted free cash flow, among other measures, to assess its financial performance and cash generating capabilities, and believes that it is useful to investors because it shows CSG’s cash available to service debt, make strategic acquisitions and investments, repurchase its common stock, pay cash dividends, and fund ongoing operations. CSG defines non-GAAP adjusted free cash flow as net cash flows from operating activities before earn-out compensation payments related to acquisitions less the purchases of software, property, and equipment.

Non-GAAP Financial Measures

Non-GAAP Operating Income and Non-GAAP Adjusted Operating Margin Percentage:

The reconciliation of GAAP operating income to non-GAAP operating income, and calculation of CSG’s non-GAAP adjusted operating margin percentage, for the indicated periods are as follows (in thousands, except percentages):