XML 33 R26.htm IDEA: XBRL DOCUMENT
v3.25.3

Basis of Presentation and Summary of Significant Accounting Policies (Policies) | 9 Months Ended
--- | ---
Sep. 30, 2025
Accounting Policies [Abstract] |
Nature of Operations | Nature of Operations Financial Institutions, Inc. (individually referred to herein as the “Parent Company,” or “Parent,” and together with its subsidiaries, collectively referred to herein as the “Company”) is a financial holding company organized in 1931 under the laws of New York State (“New York”). The Company provides diversified financial services through its subsidiaries, Five Star Bank (the “Bank”) and Courier Capital, LLC (“Courier Capital”). The Company offers a broad array of deposit, lending and other financial services to individuals, municipalities and businesses in Western and Central New York through its wholly owned New York chartered banking subsidiary, the Bank. The Bank also has commercial loan production offices in Ellicott City (Baltimore), Maryland and Syracuse, New York, and indirect lending network relationships with franchised automobile dealers in the Capital District of New York. Effective January 1, 2024, the Company exited the Pennsylvania automobile market to align our focus more fully around its core Upstate New York market. Courier Capital provides customized investment management, investment consulting and retirement plan services to individuals, businesses, institutions, foundations and retirement plans. The Company previously offered a Banking-as-a-Service (“BaaS”) business to non-bank financial service providers and other financial technology firms, or FinTechs, allowing them to provide banking services to their end users. On September 16, 2024, the Company issued a press release announcing its intent to begin an orderly wind down of its BaaS offerings, following a careful review by the Company’s executive management and Board of Directors undertaken in conjunction with its annual strategic planning process. The Company had approximately $7 million of BaaS-related deposits on the balance sheet at September 30, 2025, and expects the remaining balance to flow out in early 2026. On April 1, 2024, the Company announced and closed the sale of the assets of its former subsidiary SDN Insurance Agency, LLC (“SDN”), which provided a broad range of insurance services to personal and business clients, to NFP Property & Casualty Services, Inc., a subsidiary of NFP Corp. The sale generated $27 million in proceeds, or a pre-tax gain of $13.7 million, after selling costs, of which $13.5 million was recorded to net gain (loss) on other assets in the Company’s statement of operations in the second quarter of 2024. The all-cash transaction value represented approximately four t imes our 2023 insurance revenue. Following the sale of the assets of SDN, the Company changed the name of the entity to Five Star Advisors LLC and expects to utilize it to serve as a conduit to refer insurance business to NFP.
Basis of Presentation | Basis of Presentation The consolidated financial statements include the accounts of the Company and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. The accounting and reporting policies conform to U.S. generally accepted accounting principles (“GAAP”). Certain information and footnote disclosures normally included in financial statements prepared in conformity with GAAP have been condensed or omitted pursuant to such rules and regulations. However, in the opinion of management, the accompanying consolidated financial statements reflect all adjustments of a normal and recurring nature necessary for a fair presentation of the consolidated statements of financial condition, income, comprehensive income, changes in shareholders’ equity and cash flows for the periods indicated and contain adequate disclosures to make the information presented not misleading. These consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2024. The results of operations for any interim periods are not necessarily indicative of the results which may be expected for the entire year or any other period.
Reclassifications | Reclassifications Certain reclassifications of previously reported amounts have been made to conform to the current year’s presentation. Such reclassifications did not impact net income or shareholders’ equity as previously reported.
Use of Estimates | Use of Estimates The preparation of these financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. These estimates and assumptions are based on management’s best estimates and judgments and are evaluated on an ongoing basis using historical experience and other factors including the current economic environment. The Company adjusts these estimates and assumptions when facts and circumstances dictate. Actual results could differ from those estimates and assumptions.
Cash Flow Reporting | Cash Flow Reporting Cash and cash equivalents include cash and due from banks, federal funds sold and interest-bearing deposits in other banks. Net cash flows are reported for loans, deposit transactions and short-term borrowings. Supplemental cash flow information is summarized as follows for the nine months ended September 30, 2025, and 2024 (in thousands):
|  | 2025 |  |  | 2024 |
Supplemental information: |  |  |  |  |  |
Cash paid for interest |  | $ | 94,465 |  |  | $ | 121,197 |
Cash paid for income taxes |  |  | — |  |  |  | 3,526 |
Noncash investing and financing activities: |  |  |  |  |  |
Real estate and other assets acquired in settlement of loans |  |  | 142 |  |  |  | 181 |
Accrued and declared unpaid dividends |  |  | 6,601 |  |  |  | 5,004 |
Recent Accounting Pronouncements | Recent Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments expand the disclosure requirements of segment expenses, as well as adding disclosure of the title and position of the chief operating decision maker (“CODM”) and an explanation of how the CODM uses the reported measures of segment profit or loss in assessing segment performance and deciding how to allocate resources is also required. The amendments became effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Refer to Note 15, Segment Reporting, for disclosures required by this update. Standards Not Yet Effective In December 2023, the FASB issued ASU 2023-09, Income Tax (Topic 740): Improvements to Income Tax Disclosures. The amendments expand 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 amendments are effective for fiscal years beginning after December 15, 2024, and interim periods within fiscal years beginning after December 15, 2025. Early adoption is permitted. The adoption of this guidance will not have a material impact on the Company’s consolidated financial statements. 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. The adoption of this guidance will not have a material impact on the Company’s consolidated financial statements. Legislative Developments On July 4, 2025, the President signed H.R. 1, the “One Big Beautiful Bill Act” (the “OBBB Act”), into law. The legislation includes several changes to federal tax law that generally allow for more favorable deductibility of certain business expenses beginning in 2025, including the restoration of immediate expensing of domestic R&D expenditures, reinstatement of 100% bonus depreciation, and more favorable rules for determining the limitation on business interest expense. The OBBB Act also made certain changes to the deductibility of the cost of meals and charitable contributions that are effective for tax years beginning after December 31, 2025. The Company is currently evaluating the provisions of the OBBB Act and does not expect it to have a material impact on its consolidated financial statements.

X
- Definition Cash flow reporting. + References No definition available. + Details
Name: | fisi_CashFlowReportingPolicyTextBlock
Namespace Prefix: | fisi_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nature Of Business Operations [Policy Text Block] + References No definition available. + Details
Name: | fisi_NatureOfBusinessOperationsPolicyTextBlock
Namespace Prefix: | fisi_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of accounting policy for basis of accounting, or basis of presentation, used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483426/235-10-50-4 + Details
Name: | us-gaap_BasisOfAccountingPolicyPolicyTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of accounting policy pertaining to new accounting pronouncements that may impact the entity's financial reporting. Includes, but is not limited to, quantification of the expected or actual impact. + References No definition available. + Details
Name: | us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of accounting policy for reclassification affecting comparability of financial statement. Excludes amendment to accounting standards, other change in accounting principle, and correction of error. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 205 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483504/205-10-50-1 + Details
Name: | us-gaap_PriorPeriodReclassificationAdjustmentDescription
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478671/942-235-S50-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-05(b)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477314/942-235-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 275 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482861/275-10-50-12 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 275 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482861/275-10-50-9 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 275 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482836/275-10-55-6 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 275 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482861/275-10-50-6 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 275 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482861/275-10-50-4 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -SubTopic 10 -Topic 275 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482861/275-10-50-1 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -SubTopic 10 -Topic 275 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482861/275-10-50-1 + Details
Name: | us-gaap_UseOfEstimates
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration