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UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The following unaudited pro forma condensed combined financial information is presented by Constellation Energy Corporation, a Pennsylvania corporation ("CEG Parent"), and Constellation Energy Generation, LLC (“Constellation”, together with CEG Parent, the "Company") to illustrate the estimated effects of the proposed acquisition of Calpine Corporation, a Delaware corporation ("Calpine"), in accordance with the terms of the Agreement and Plan of Merger, dated January 10, 2025 ("the Merger Agreement"). Pursuant to the Merger Agreement, Calpine will become an indirect and wholly owned subsidiary of Constellation (the "Merger").

Under the terms of the Merger Agreement, the merger consideration will consist of (A) 50 million newly issued shares of CEG Parent common stock, no par (the "Stock Consideration") and (B) $4,500 million in cash (the "Cash Consideration" and together with the Stock Consideration, "Merger Consideration").

The Unaudited Pro Forma Condensed Combined Statements of Operations for the nine months ended September 30, 2025 and the year ended December 31, 2024, give effect to the Merger as if it was completed on January 1, 2024. The Unaudited Pro Forma Condensed Combined Balance Sheets give effect to the Merger as if it was completed on September 30, 2025. The unaudited pro forma condensed combined financial information (“unaudited pro forma financial statements”) has been derived from, and should be read in conjunction with, (i) the historical audited consolidated financial statements of the Company and accompanying notes included in the Company's annual report on Form 10-K as of and for the year ended December 31, 2024, (ii) the historical unaudited consolidated financial statements of the Company and accompanying notes included in the Company's quarterly report on Form 10-Q as of and for the nine months ended September 30, 2025, (iii) the historical audited consolidated condensed financial statements of Calpine and accompanying notes as of and for the year ended December 31, 2024, filed as to this Current Report on Form 8-K, and (iv) the historical unaudited consolidated condensed financial statements of Calpine and accompanying notes as of and for the nine months ended September 30, 2025, filed as .2 to this Current Report on Form 8-K.

In accordance with Article 11 of Regulation S-X, the unaudited pro forma financial statements are prepared for illustrative and informational purposes only and are not intended to represent what combined results of operations would have been had the acquisition occurred on the date indicated, or what they will be for any future periods. In order to satisfy regulatory requirements, the Company has agreed to divest certain Calpine plants, as well as Calpine's interest in an equity method investment. The unaudited pro forma financial statements have been adjusted to reflect the planned divestitures. The unaudited pro forma financial statements do not reflect the realization of any expected cost savings or other synergies as a result of the acquisition.

In connection with the proposed Merger, Constellation commenced private exchange offers (the "Exchange Offers") and related consent solicitations (the "Consent Solicitations") on December 9, 2025, whereupon contingent upon the Merger closing, up to $2,400 million of aggregate principal amount of fixed rate Constellation debt will be exchanged for certain outstanding indebtedness of Calpine (the "Debt Exchange"). The unaudited pro forma financial statements do not give effect to the estimated impacts of the Exchange Offers and Consent Solicitations. The Company does not expect the Debt Exchange to have a material impact, therefore no pro forma adjustments related to the Debt Exchange are reflected in the accompanying unaudited pro forma financial statements. The Merger is not subject to a financing condition or the completion of the Debt Exchange or Consent Solicitations related to Calpine's outstanding indebtedness.

The unaudited pro forma financial statements have been prepared using the acquisition method of accounting for business combinations under generally accepted accounting principles in the United States (“US GAAP”) whereby the Company is considered the accounting acquirer. Under the acquisition method of accounting, the Merger Consideration will be allocated to the identifiable assets acquired and liabilities assumed based upon their estimated fair values as of the closing of the Merger, and any excess value of the Merger Consideration over the acquired net assets will be recognized as goodwill, if applicable. The assets acquired and liabilities assumed of Calpine have been measured based on various preliminary estimates using assumptions that the Company believes are reasonable, based on information that is currently available. The Company expects to complete the final purchase price allocation during the 12-month period from closing of the Merger. Due to the unaudited pro forma financial statements being prepared based on preliminary estimates of the net assets acquired as of September 30, 2025, the final purchase price allocation and the resulting effect on financial position and results of operations may differ significantly from the pro forma amounts included herein. As a result, the pro forma adjustments are preliminary and are subject to change as additional information becomes available and as additional analysis is performed and these changes may be material.

CONSTELLATION ENERGY CORPORATION AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

As of September 30, 2025

(in millions)

CONSTELLATION ENERGY CORPORATION AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

As of September 30, 2025

(in millions)

See notes to unaudited pro forma condensed combined financial statements

CONSTELLATION ENERGY CORPORATION AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the nine months ended September 30, 2025

(in millions, except per share data)

See notes to unaudited pro forma condensed combined financial statements

CONSTELLATION ENERGY CORPORATION AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the year ended December 31, 2024

(in millions, except per share data)

See notes to unaudited pro forma condensed combined financial statements

CONSTELLATION ENERGY GENERATION, LLC AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

As of September 30, 2025

(in millions)

CONSTELLATION ENERGY GENERATION, LLC AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

As of September 30, 2025

(in millions)

See notes to unaudited pro forma condensed combined financial statements

CONSTELLATION ENERGY GENERATION, LLC AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the nine months ended September 30, 2025

(in millions, except per share data)

See notes to unaudited pro forma condensed combined financial statements

CONSTELLATION ENERGY GENERATION, LLC AND SUBSIDIARY COMPANIES

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the year ended December 31, 2024

(in millions, except per share data)

See notes to unaudited pro forma condensed combined financial statements

Notes to Unaudited Pro Forma Condensed Combined Financial Statements

1. Basis of Presentation

The unaudited pro forma financial statements were derived from historical consolidated financial statements of the Company and Calpine which were prepared in accordance with US GAAP. Amounts disclosed relate to CEG Parent and Constellation unless specifically noted. Certain accounting policy alignment and reclassification adjustments were made to conform Calpine's historical financial statement presentation with the Company's historical financial statement presentation, see Note 3 - Accounting Policy Alignment and Reclassification Adjustments for additional information. Further, there were no material intercompany transactions between the Company and Calpine for the nine months ended September 30, 2025 and for the year ended December 31, 2024.

The Merger is being accounted for as a business combination using the acquisition method of accounting under US GAAP, which requires assets acquired and liabilities assumed to be recorded at their acquisition date fair value. The initial accounting for the Merger is not complete because the valuations necessary to assess the fair values of certain assets acquired and liabilities assumed are preliminary. Therefore, the allocation of the purchase price as reflected in the unaudited pro forma financial statements is based upon management's preliminary estimates of the fair value of the assets acquired and liabilities assumed. The preliminary amounts recognized are subject to revision until the valuations are completed and to the extent that additional information is obtained about the facts and circumstances that existed as of the acquisition date. Differences between these preliminary estimates and the final acquisition accounting may occur and these differences could have a material impact on the accompanying unaudited pro forma financial statements and the combined company’s future results of operations and financial position.

2. Preliminary Purchase Price Allocation

The table below represents the preliminary calculation of estimated Merger Consideration for the purposes of the unaudited pro forma financial statements.

The preliminary estimated Merger Consideration could significantly differ from the amounts presented due to movements in CEG Parent’s stock price until the Merger is consummated. A sensitivity analysis related to the fluctuation in CEG Parent’s stock price was performed to assess the impact that a hypothetical change of 10% on the closing price of CEG Parent's common stock on December 3, 2025 would have on the estimated Merger Consideration and preliminary goodwill at the closing of the Merger:

Under the acquisition method of accounting, the identifiable assets acquired and liabilities assumed from Calpine are recognized and measured at fair value. The purchase price allocation is preliminary and is based on available information and certain assumptions, which the Company believes are reasonable.

The following table presents a preliminary allocation of the estimated Merger Consideration to the fair values of the identifiable assets acquired and liabilities assumed from Calpine, based on Calpine's balance sheet as of September 30, 2025, as adjusted for accounting policy alignment and reclassification adjustments as well as acquisition accounting adjustments shown below.

3. Accounting Policy Alignment and Reclassification Adjustments

Certain reclassification and accounting policy alignment adjustments have been made to conform Calpine's historical financial statement presentation to the Company's historical financial statement presentation and accounting policies. During the preparation of these unaudited pro forma financial statements, the Company performed a preliminary analysis of Calpine’s historical financial information to identify any differences in accounting policies that would require reclassification of Calpine's historical financial statement presentation to conform to the Company's accounting policies. Aside from the accounting policy alignment and reclassification adjustments identified herein, the Company is not aware of any material differences between the accounting policies of the Company and Calpine.

The following reflects the accounting policy alignment and reclassification adjustments made to present Calpine’s historical consolidated balance sheet as of September 30, 2025 in conformity with that of the Company:

Calpine Corporation and Subsidiaries

Consolidated Condensed Balance Sheet

As of September 30, 2025

(In millions)

Calpine Corporation and Subsidiaries

Consolidated Condensed Balance Sheet

As of September 30, 2025

(In millions)

The following accounting policy alignment and reclassification adjustments were made to present the Calpine’s historical consolidated statement of operations for the nine months ended September 30, 2025 in conformity with that of the Company:

Calpine Corporation and Subsidiaries

Consolidated Condensed Statement of Operations

For the nine months ended September 30, 2025

(In millions)

The following accounting policy alignment and reclassification adjustments were made to present the Calpine’s historical consolidated statement of operations for the year ended December 31, 2024 in conformity with that of the Company:

Calpine Corporation and Subsidiaries

Consolidated Condensed Statement of Operations

For the year ended December 31, 2024

(In millions)

4. Adjustments to Unaudited Pro Forma Financial Statements

A. Reflects a reduction of $4,500 million to reflect the cash portion of the Merger Consideration.

B. Reflects the reclassification of certain inventories related to the plants classified as held for sale. At the time of this filing, the proceeds from the sale of these plants are unknown, and the effects of the sale of assets and liabilities expected to be divested, including the effect to historical operations, are not presented. As such, pro forma adjustments to the unaudited pro forma condensed combined statement of operations are limited to the removal of depreciation and amortization expense (see Note 4M). Any difference between the estimated carrying values of the plants post-Merger consummation and the final sale price will result in the recognition of a gain or loss.

C. Reflects a step-up of $9,845 million in the fair value of property, plant and equipment acquired, net of assets held for sale of $3,331 million. The held for sale amounts include both the fair value step-up for all plants currently classified as held for sale and the historical book value of certain plants that were not presented as held for sale in the Historical Calpine as Conformed Balance Sheet. Fair value was estimated using significant assumptions about operating strategies and estimates of future cash flows, which required assessments of current and projected market conditions. Forecasting future cash flows requires assumptions regarding forecasted commodity prices for the sale of power and purchases of fuel and the expected operations of assets. The estimated remaining useful lives of the acquired property, plant and equipment range from 2 to 40 years. The cash flows were discounted using rates between 9% and 14.5%, depending on the related technology and market in which each respective asset operates, and reflect the risks inherent in the future cash flows. A 0.5% change in the discount rates would increase or decrease the fair value of the property, plant, and equipment by approximately $730 million.

D. Primarily relates to adjustments to measure acquired unamortized energy contracts and other intangibles at their preliminary estimated fair value (see table below). Unamortized energy contracts represent non-derivative energy contracts acquired from Calpine. The initial amount recorded for the unamortized energy contracts is the difference between the market value of the contracts at the time of acquisition and the contract value based on the terms of each contract. The unamortized energy contract assets and liabilities are amortized over the life of the contract in relation to the expected realization of the underlying cash flows. Amortization of the unamortized energy contract assets and liabilities is recorded in Operating revenues or Purchased power and fuel expense, depending on the nature of the underlying contract.

For the nine months ended September 30, 2025, the amortization of Unamortized Energy Contracts resulted in an increase of $129 million to Operating revenue and an increase of $27 million to Purchased power and fuel expense. For the year ended December 31, 2024, the amortization of Unamortized Energy Contracts resulted in a decrease of $19 million to Operating revenue and an increase of $25 million to Purchased power and fuel expense. For the nine months ended September 30, 2025, and year ended December 31, 2024, the amortization expense related to customer relationships and trade names was not material.

The following table summarizes the estimated future amortization related to the unamortized energy contracts for each of the next 5 calendar years. The amounts below reflect a net increase (decrease) to Operating income (pre-tax).

E. Reflects the elimination of Calpine's historical goodwill and the recognition of preliminary estimated goodwill as a result of the Merger. Refer to Note 2 for the preliminary purchase price allocation.

F. Represents the estimated Merger-related transaction costs yet to be expensed or accrued in the Company's historical financial statements through September 30, 2025. Estimated Merger-related transaction costs include investment banker, advisory, legal, valuation and other professional fees. The Company's total estimated Merger-related transaction costs amount to $146 million, with $49 million in expense recognized to date, resulting in a pro forma adjustment of $97 million.

G. Reflects an adjustment to measure the long-term debt, net of amounts due within one year, at its estimated fair value.

H. Represents the estimated tax impact of the pro forma adjustments based on an assumed tax rate of 25.3%. The assumed tax rate reflects a blended average statutory rate based on the assumed jurisdiction for the pro forma adjustments and current structure. The effective tax rate of the Company following the acquisition could be different depending on post-acquisition activities, including cash needs, the geographical mix of income, and changes in tax law. Because the tax rates used for the unaudited pro forma condensed combined statement of operations are estimated, the blended rate will likely vary from the actual effective tax rate in periods subsequent to the completion of the acquisition. This determination is preliminary and subject to change based upon the final determination of the fair value of the acquired assets and assumed liabilities.

I. Reflects an increase of $83 million to asset retirement obligations, primarily due to updated estimated decommissioning costs and the application of the relevant Company discount rates as of the pro forma balance sheet date. The impact to accretion expense related to the asset retirement obligations adjustment was not material for the nine months ended September 30, 2025, and the year ended December 31, 2024.

J. The following tables summarize the transaction accounting adjustments impacting the equity balances of CEG Parent and Constellation as combined with Calpine:

K. This adjustment reflects the impact to the combined company of reporting the sale and purchase of electricity in the spot market on a net hourly basis in either Operating revenues or Purchased power and fuel expense within each region, depending on our net hourly position. Operating revenues and Purchased power and fuel both decreased by $796 million and $826 million for the nine months ended September 30, 2025 and for the year ended December 31, 2024, respectively. Additionally, Operating revenues and Purchased power and fuel both decreased by $147 million and $552 million for the nine months ended September 30, 2025 and year ended December 31, 2024, respectively, to align with the Company's classification of derivative revenues and expenses.

L. Reflects adjustment for stock-based compensation related to the issuance of CEG Parent's common stock to certain members of Calpine's management, with the stock awards subject to vesting based on continued employment.

M. Reflects incremental depreciation expense related to the preliminary fair value of property, plant, and equipment acquired, net of assets held for sale. Depreciation is ceased for assets held for sale, thus Calpine's historical depreciation expense is eliminated for those assets.

N. Reflects an adjustment to decrease interest expense by $53 million for the nine months ended September 30, 2025, and $112 million for the year ended December 31, 2024. This adjustment is attributable to Calpine's paydown of its debt, lower interest rates, and the removal of amortization associated with the historical debt discount.

O. The unaudited pro forma combined basic and diluted earnings per share calculations are based on the average basic and diluted shares of CEG Parent. The following table summarizes the computation of the unaudited pro forma basic and diluted earnings per share: