PROSPERITY BANCSHARES INC New Standards Disclosure

New Accounting Standards

Accounting Standards Updates (“ASU”)

ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements. ASU 2025‑11 clarifies interim disclosure requirements, including providing a comprehensive list of interim disclosure requirements under U.S. GAAP and a disclosure principle that requires entities to disclose events since the last annual reporting period that have a material impact on the entity. The standard is effective for interim periods within annual reporting periods beginning after December 15, 2027. The Company does not expect the adoption of ASU 2025-11 to have a significant impact on its financial statements.

ASU 2025-08, Financial Instruments—Credit Losses (Topic 326): Purchased Loans. Under ASU 2025-08, loans acquired without credit deterioration and deemed “seasoned” will be considered purchased seasoned loans and accounted for using the gross-up approach at acquisition (i.e., record the loan at its purchase price and separately record an allowance for expected credit losses). Seasoned loans include all loans acquired in a business combination that do not have “more-than-insignificant” deterioration of credit quality since origination, as well as loans purchased at least 90 days after origination where the purchaser was not involved in the origination of the loans. ASU 2025-08 is effective for annual and interim periods beginning in our fiscal 2028 with early adoption permitted. The Company is evaluating the impact the adoption of ASU 2025-08 will have on its financial statements.

ASU 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. ASU 2025-06 modernizes the accounting for internal-use software costs. Under this ASU, software development costs are capitalized when (i) management has authorized and committed to funding the software project and (ii) it is probable that the project will be completed and the software will be used to perform the function intended. ASU 2025-06 is effective for fiscal years beginning after December 15, 2027, and interim reporting periods, with early adoption permitted. The Company does not expect the adoption of ASU 2025-06 to have a significant impact on its financial statements.

ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. ASU 2024-03 requires public companies to disclose, in the notes to the financial statements, specific information about certain costs and expenses at each interim and annual reporting period. This includes disclosing amounts related to employee compensation, depreciation, and intangible asset amortization. In addition, public companies will need to provide a qualitative description of the amounts remaining in relevant expense captions that are not separately disaggregated quantitatively. ASU 2024-03 is effective for public business entities for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Implementation of ASU 2024-03 may be applied prospectively or retrospectively. The Company does not expect the adoption of ASU 2024-03 to have a significant impact on its financial statements.

ASU 2024-01, Compensation—Stock Compensation (Topic 718): Scope Application of Profits Interest and Similar Awards. ASU 2024-01 clarifies the scope application of profits interest and similar awards by adding illustrative guidance to help entities determine whether profits interest and similar awards should be accounted for as share-based payment arrangements within the scope of FASB ASC 718, “Compensation—Stock Compensation.” However, this amendment does not change the intent of that guidance, nor how it should be applied. The ASU’s amendments are effective for fiscal years beginning after December 15, 2024, including

interim periods within those years. ASU 2024-01 became effective for the Company on December 31, 2024 and did not have a significant impact on the Company’s financial statements.

ASU 2023-09, Income Taxes (Topic 740): Improvements to Income. ASU 2023-09 focuses on the rate reconciliation and income taxes paid. ASU 2023-09 requires a public business entity to disclose, on an annual basis, a tabular rate reconciliation using both percentages and currency amounts, broken out into specified categories with certain reconciling items further broken out by nature and jurisdiction to the extent those items exceed a specified threshold. In addition, all entities are required to disclose income taxes paid, net of refunds received disaggregated by federal, state/local, and foreign and by jurisdiction if the amount is at least 5% of total income tax payments, net of refunds received. The Company adopted ASU 2023-09 as of December 31, 2025 on a retrospective basis, and it did not have a significant impact on the Company’s financial statements. For further discussion of the Company’s income taxes, See Note 10 to the consolidated financial statements.

ASU 2023-07, Segment Reporting (Topic 280) - Improvement to Reportable Segment Disclosures. ASU 2023-07 amends the disclosure requirements related to segment reporting primarily through enhanced disclosure about significant segment expenses that are regularly provided to the chief operating decision maker and by requiring disclosure of segment information on an annual and interim basis. The amendments in this update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. ASU 2023-07 became effective for the Company on December 31, 2024 and did not have a significant impact on the Company’s financial statements.