FINANCIAL INSTITUTIONS INC New Standards Disclosure

Accounting Standards Recently Adopted or Issued

Standards Adopted in 2025

In December 2023, the FASB issued Accounting Standards Update (“ASU”) 2023-09, Income Tax (Topic 740): Improvements to Income Tax Disclosures. The ASU expands the disclosure requirements of income taxes, primarily related to the income tax rate reconciliation and income taxes paid. The guidance also eliminates certain existing disclosure requirements related to uncertain tax positions and unrecognized deferred income tax liabilities. The Company adopted ASU 2023-09 for the year ended December 31, 2025 and applied the new disclosure requirements prospectively in Note 17, Income Taxes.

Standards Issued – Not Yet Effective

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. The amendments require the disclosure of specified information about certain costs and expenses, in the notes to the financial statements. The amendments are effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. This ASU affects financial statement disclosure only, and will not have a material impact on the Company’s operations or financial condition.

In November 2025, the FASB issued ASU 2025-08, Financial Instruments—Credit Losses (Topic 326): Purchased Loans. The ASU introduces the concept of purchased seasoned loans and requires certain acquired loans (excluding credit cards) that have not experienced significant credit deterioration since origination to be accounted for using the gross-up method. The amendments clarify initial and subsequent measurement, including recognition of an allowance for credit losses at acquisition with an offsetting gross-up to the purchase price, and require purchased seasoned loans to follow the same interest income recognition model as originated financial assets. The ASU also updates disclosure requirements to include separate presentation of the initial allowance recognized for purchased seasoned loans. The amendments in this Update are effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods within those annual reporting periods, and should be applied prospectively to loans that are acquired on or after the initial application date. Early adoption is permitted. The Company is currently evaluating the impact of this ASU, but it is not expected to have a material impact on its financial statements.

In November 2025, the FASB issued ASU 2025-09, Derivative and Hedging (Topic 815): Hedge Accounting Improvements. The five issues addressed in this Update are intended to better reflect those strategies in financial reporting by enabling entities to achieve and maintain hedge accounting for highly effective economic hedges of forecasted transactions. The amendments are effective for annual and reporting periods beginning after December 15, 2026, and interim periods within those annual reporting periods, and should be applied on a prospective basis for all hedging relationships. An election may be made to adopt the amendments in this update for hedging relationships that exist as of the date of adoption. The Company is currently evaluating the impact of this ASU, but it does not expect it to have a material impact on its consolidated financial statements.

In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements. The amendments provide guidance on accounting and disclosures specific to interim reporting. The amendments are effective for interim reporting periods in fiscal years beginning after December 15, 2027. Early adoption is permitted. The Company is currently assessing this ASU and the impact, if any, it will have on disclosures within our interim financial statements.