Accounting Policies Recently Adopted

Except for the changes detailed below, Trustmark has consistently applied its accounting policies to all periods presented in the accompanying consolidated financial statements.

ASU 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures.” Issued in November 2023, ASU 2023-07 is intended to improve disclosures about a public entity’s reportable segments and address requests from investors and other allocators of capital for additional, more detailed information about a reportable segment’s expenses. The amendments of ASU 2023-07 require a public entity to disclose, on an annual and interim basis, significant segment expenses that are regularly provided to the chief operating decision maker (CODM) and included within each reported measure of segment profit or loss, and an amount for other segment items by reportable segment and a description of its composition. The other segment items category is the difference between segment revenue less the significant expenses disclosed and each reported measure of segment profit or loss. ASU 2023-07 also requires a public entity to provide all annual disclosures about a reportable segment’s profit or loss and assets currently required under FASB ASC Topic 280 in interim periods. The amendments of ASU 2023-07 clarify that if the CODM uses more than one measure of a segment's profit or loss in assessing segment performance and deciding how to allocate resources, a public entity may report one or more of those additional measures of segment profit. However, at least one of the reported segment profit or loss measures (or the single reported measure if only one is disclosed) should be the measure that is most consistent with the measurement principles used in measuring the corresponding amounts in the public entity's consolidated financial statements. ASU 2023-07 requires a public entity to disclose the title and position of the CODM, together with an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. In addition, ASU 2023-07 requires that a public entity with a single reportable segment provide all the disclosures required by the amendments of ASU 2023-07 and all existing segment

disclosures in FASB ASC Topic 280. The amendments of ASU 2023-07 were effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The amendments in ASU 2023-07 should be applied retrospectively to all periods presented on the financial statements. Upon implementation, the segment expense categories and amounts disclosed in the prior periods should be based on the significant segment expense categories identified and disclosed in the period of adoption. Trustmark adopted the amendments of ASU 2023-07 related to annual disclosure requirements effective January 1, 2024, and the newly required annual disclosures were included in Note 21 – Segment Information of the 2024 Annual Report. Trustmark adopted the amendments of ASU 2023-07 related to interim disclosure requirements effective January 1, 2025, and the newly required interim disclosures are included in Note 19 - Segment Information of this report. Adoption of ASU 2023-07 did not have a material impact to Trustmark’s consolidated financial statements or results of operations.

ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” Issued in December 2023, ASU 2023-09 is intended to improve the disclosures for income taxes to address requests from investors, lenders, creditors and other allocators of capital (collectively, "investors") that use the financial statements to make capital allocation decisions. During the FASB's 2021 agenda consultation process and other stakeholder outreach, investors highlighted that the current system of income tax disclosures does not provide enough information to understand the tax provision for an entity that operates in multiple jurisdictions. Investors currently rely on the rate reconciliation table and other disclosures, including total income taxes paid in the statement of cash flows, to evaluate income tax risks and opportunities. The amendments in ASU 2023-09 will require consistent categories and greater disaggregation of information in the rate reconciliation disclosure as well as disclosure of income taxes paid disaggregated by jurisdiction. The amendments of ASU 2023-09 are effective for annual periods beginning after December 15, 2024, and early adoption is permitted for annual financial statements that have not yet been issued or made available for issuance. Trustmark adopted the amendments of ASU 2023-09 effective January 1, 2025, and will include the required disclosures in its Annual Report on Form 10-K for the year ending December 31, 2025. Trustmark is currently evaluating the changes to disclosures required by ASU 2023-09; however, adoption of ASU 2023-09 is not expected to have a material impact to Trustmark’s consolidated financial statements or results of operations.

Pending Accounting Pronouncements

ASU 2024-03, “Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses.” Issued in November 2024, ASU 2024-03 with the objective of providing investors with more decision-useful information regarding a public business entity's expenses by enhancing disclosures on income statement expenses. Investor feedback indicated a strong preference for the disclosure of disaggregated financial reporting information as a top priority for the FASB. Detailed knowledge of an entity's expenses is crucial for understanding its prospects for future cash flows and for making performance comparisons over time and with other entities. Investors emphasized that information regarding cost of sales, selling, general, and administrative expenses, employee compensation costs, depreciation and amortization, and research and development expenditure would enhance their comprehension of an entity's cost structure and ability to forecast future cash flows. The ASU applies exclusively to public business entities and mandates additional disclosures about specific expense categories on both annual and interim bases in the notes to financial statements that are not currently required. The amendments do not alter or eliminate existing expense disclosure requirements nor change requirements for presenting expenses on the face of the income statement. However, they do specify that certain existing disclosures must now appear in the same tabular format as the new disaggregation requirements. The FASB issued ASU 2025-01 in January 2025, clarifying that the amendments in ASU 2024-03 are effective for public business entities for annual reporting periods beginning after December 15, 2026, and for interim reporting periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. Trustmark intends to adopt the amendments of ASU 2024-03 effective January 1, 2027, and will include the required annual disclosures in its Annual Report on Form 10-K for the year ending December 31, 2027, and required interim disclosures in its Quarterly Report on Form 10-Q for the period ending March 31, 2028. Trustmark is currently evaluating the changes to disclosures required by ASU 2024-03; however, adoption of ASU 2024-03 is not expected to have a material impact to Trustmark’s consolidated financial statements or results of operations.