
☑ANNUAL REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscalyear ended December31, 2025OR ☐TRANSITION REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period fromto Commission file number 0-16759FIRST FINANCIAL CORPORATION(Exact name of registrant as specified in its charter) Indiana35-1546989(State of Incorporation)(I.R.S. Employer Identification Number)One First Financial PlazaTerre Haute, Indiana47807(Address of Registrant’s Principal Executive Offices)(Zip Code) (812) 238-6000(Registrant’s Telephone Number, Including Area Code)Securities registered pursuant to Section12(b)of the Act: Name of each exchange on whichregistered The NASDAQ Stock Market LLC Securities registered pursuant to Section12(g)of the Act:None Indicate by check mark if the registrant is a well-known-seasoned issuer, as defined in Rule405 of the Securities Act. Yes☐No☑ Indicate by check mark if the registrant is not required to file reports pursuant to Section13 or Section15(d)of the Act.Yes☐No☑ Indicate by check mark whether the registrant (1)has filed all reports required to be filed by Section13 or 15(d)of the SecuritiesExchange Act of 1934 during the preceding 12months (or for such shorter period that the registrant was required to file suchreports), and (2)has been subject to such filing requirements for the past 90days.Yes☑No☐ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submittedpursuant to Rule405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12months (or for such shorter period thatthe registrant was required to submit such files). Yes☑No☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smallerreporting company. See definition of “accelerated filer”, “large accelerated filer”, and “smaller reporting company” in Rule12b-2 ofthe Exchange Act of 1934. Large accelerated filer☐Accelerated filer☑Non-accelerated filer☐Smaller reporting company☐Emerging growth company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section7(a)(2)(B)of the Securities Act.☐ Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of theeffectiveness of its internal control over financial reporting under Section404(b)of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) bythe registered public accounting firm that prepared or issued its audit report.☑ If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of theregistrant included in the filing reflect the correction of an error to previously issued financial statements.☐ Table of Contents Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-basedcompensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule12b-2 of the Act).Yes☐No☑ As of June30, 2025 the aggregate market value of the stock held by non-affiliates of the registrant based on the average bid and askprices of such stock was $584,183,576. (For purposes of this calculation, the Corporation excluded the stock owned by certainbeneficial owners and management and the Corporation’s Employee Stock Ownership Plan.) Shares of Common Stock outstanding as of March2, 2026—11,891,896 shares. DOCUMENTS INCORPORATED BY REFERENCE Portions of the Definitive Proxy Statement for the First Financial Corporation Annual Meeting of Shareholders to be held April15,2026 are incorporated by reference into PartIII. FIRST FINANCIAL CORPORATION2025 ANNUAL REPORT ON FORM10-KTABLE OF CONTENTS PART IItem 1. Business4Item 1A. Risk Factors15Item 1B. Unresolved Staff Comments31Item 1C. Cybersecurity31Item 2. Properties32Item 3. Legal Proceedings32Item 4. Mine Safety Disclosures33PART IIItem 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of EquitySecurities34Item 6. Selected Financial Data36Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations37Item 7A. Quantitative and Qualitative Disclosures about Market Risk49Item 8. Financial Statements and Supplementary Data50Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosures106Item 9A. Controls and Procedures106Item 9B. Other Information106Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections106PART IIIItem 10. Directors, Executive Officers and Corporate Governance106Item 11. Executive Compensation106Item 1