PROSPERITY BANCSHARES INC

The preparation of financial statements in conformity with GAAP requires the Company to establish accounting policies and make estimates that affect amounts reported in the consolidated financial statements. An accounting estimate requires assumptions and judgments about uncertain matters that could have a material effect on the consolidated financial statements. Estimates are made using facts and circumstances known at a point in time. Changes in those facts and circumstances could produce results substantially different from those estimates. The Company’s accounting policies are described in detail in Note 1 to the consolidated financial statements, appearing elsewhere in this Annual Report on Form 10-K. The Company believes that of its significant accounting policies, the following may involve a higher degree of judgment and complexity:

Business Combinations—Generally, acquisitions are accounted for under the acquisition method of accounting in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 805, “Business Combinations.” A business combination occurs when the Company acquires net assets that constitute a business and obtains control over that business. Business combinations are effected through the transfer of consideration consisting of cash and/or common stock and are accounted for using the acquisition method. Accordingly, the assets and liabilities of the acquired business are recorded at their respective fair values at the acquisition date. Determining the fair value of assets and liabilities, especially the loan portfolio, is a process involving significant judgment regarding methods and assumptions used to calculate estimated fair values. Fair values are subject to refinement for up to one year after the closing date of the acquisition as information relative to closing date fair values becomes available. The results of operations of an acquired entity are included in the Company’s consolidated results from the acquisition date, and prior periods are not restated.

Allowance for Credit Losses— The allowance for credit losses is accounted for in accordance with FASB ASC Topic 326, “Financial Instruments-Credit Losses” (“CECL”), which uses an expected loss methodology that is referred to as the current expected credit loss methodology. CECL requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is an allowance available for losses on loans and held-to-maturity securities that is deducted from the amortized cost basis to estimate the net amount expected to be collected. The allowance for credit losses is adjusted through charges to earnings in the form of a provision for credit losses. All losses are charged to the allowance when the loss actually occurs or when a determination is made that such a loss is likely and can be reasonably estimated. Recoveries are credited to the allowance at the time of recovery.

The Company’s allowance for credit losses consists of two elements: (1) specific valuation allowances based on expected losses on impaired loans and certain purchased credit-deteriorated loans (“PCD”); and (2) a general valuation allowance based on historical lifetime loan loss experience, current economic conditions, reasonable and supportable forecasted economic conditions and other qualitative risk factors both internal and external to the Company. Based on an evaluation of the portfolio, management presents a quarterly review of the allowance for credit losses to the Bank’s Board of Directors, indicating any change in the allowance since the last review and any recommendations as to adjustments in the allowance. In making its evaluation, management considers factors such as historical lifetime loan loss experience, the amount of nonperforming assets and related collateral, the volume, growth and composition of the portfolio, current economic conditions and reasonable and supportable forecasted economic conditions that may affect borrower ability to pay and the value of collateral, the evaluation of the portfolio through its internal loan review process and other relevant factors. Portions of the allowance may be allocated for specific credits; however, the entire allowance is available for any credit that, in management’s judgment, should be charged off. Charge-offs occur when loans are deemed to be uncollectible. Based on this evaluation, management has established an allowance for credit losses that it believes is management’s best estimate of current expected credit losses in the Company’s loan portfolio.

The Company evaluates all restructurings, including restructurings for borrowers experiencing financial difficulty, to determine whether they result in a new loan or a continuation of an existing loan. In accordance with ASC 326, the Company only establishes a specific reserve for modifications to borrowers experiencing financial difficulty when the loan is identified as impaired. The effect of most modifications of loans made to borrowers who are experiencing financial difficulty is already included in the allowance for credit losses because of the measurement methodologies used to estimate the allowance. The Company adjusts the terms of loans for certain borrowers when it believes such changes will help its customers manage their loan obligations and increase the collectability of the loans. Modifications to borrowers experiencing financial difficulty may include but are not limited to changes in committed loan amount, interest rate, amortization, note maturity, borrower, guarantor, collateral, forbearance, forgiveness of principal or interest, and other actions intended to minimize economic loss and to avoid foreclosure or repossession of collateral. The approval of modifications of loans for borrowers experiencing financial difficulty are handled on a case-by-case basis. For further discussion of the methodology used in the determination of the allowance for credit losses, see “Accounting for Acquired Loans and the Allowance for Acquired Credit Losses”, “Financial Condition—Allowance for Credit Losses” sections below and Note 1 and Note 5 to the consolidated financial statements.

Accounting for Acquired Loans and the Allowance for Acquired Credit Losses— The Company accounts for its acquisitions using the acquisition method of accounting. Accordingly, the assets, including loans, and liabilities of the acquired entity were recorded at their fair values at the acquisition date. These fair value estimates associated with acquired loans, based on a discounted cash flow model, include estimates related to market interest rates and undiscounted projections of future cash flows that incorporate expectations of prepayments and the amount and timing of principal, interest and other cash flows, as well as any shortfalls thereof. For further discussion of the methodology used in the determination of the allowance for credit losses for acquired loans, see “Accounting for Acquired Loans and the Allowance for Acquired Credit Losses” in Note 1 to the consolidated financial statements and “Financial Condition—Allowance for Credit Losses on Loans” below.

Goodwill and Intangible Assets—Goodwill and intangible assets that have indefinite useful lives are subject to an impairment test at least annually, or more often, if events or circumstances indicate that it is more likely than not that the fair value of the Company’s reporting unit is below the carrying value of its equity. Under FASB ASC Topic 350-20,“Intangibles—Goodwill and Other—Goodwill,” companies have the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining the need to perform step one of the annual test for goodwill impairment. An entity has an unconditional option to bypass the qualitative assessment described in the following paragraph for any reporting unit in any period and proceed directly to performing the first step of the goodwill impairment test. An entity may resume performing the qualitative assessment in any subsequent period. If the estimated fair value of the reporting unit exceeds its carrying value, goodwill of the reporting unit is not impaired.

The Company had no intangible assets with indefinite useful lives at December 31, 2025. Core deposit intangible assets that are subject to amortization are being amortized on a non-pro rata basis over the years expected to be benefited, which the Company believes is between ten and fifteen years. These core deposit intangible assets are reviewed for impairment if circumstances indicate their value may not be recoverable based on a comparison of fair value to carrying value. The Company performs an evaluation annually, and more frequently if a triggering event occurs, of whether any impairment of the goodwill and other intangibles has occurred. Based on the Company’s annual goodwill impairment test as of October 1, 2025, management does not believe any of its goodwill is impaired as of December 31, 2025, because the fair value of the Company’s equity exceeded its carrying value. While the Company believes no impairment existed at December 31, 2025, under accounting standards applicable at that date, different conditions or assumptions, or changes in cash flows or profitability, if significantly negative or unfavorable, could have a material adverse effect on the outcome of the Company’s impairment evaluation and financial condition or future results of operations.