FIRST FINANCIAL BANCORP /OH/

This Current Report on Form 8-K is being filed in connection with the closing on January 1, 2026 of the merger of BankFinancial Corporation (“BankFinancial”), a Maryland corporation, with and into First Financial Bancorp. (the “Company”), an Ohio corporation (the “Merger”), with the Company as the surviving corporation in the Merger, pursuant to the Agreement and Plan of Merger, dated as of August 11, 2025 (the “Merger Agreement”), by and between the Company and BankFinancial.

Item 2.01 Completion of Acquisition or Disposition of Assets.

On January 1, 2026, the Company completed its previously announced Merger with BankFinancial pursuant to the Merger Agreement.

Immediately following the Merger, and also effective as of January 1, 2026, BankFinancial’s wholly owned banking subsidiary, BankFinancial, National Association, merged with and into First Financial’s wholly owned banking subsidiary, First Financial Bank (the “Bank Merger”), with First Financial Bank continuing as the surviving bank in the Bank Merger.

Upon the terms and subject to the conditions set forth in the Merger Agreement, at the effective time (the “Effective Time”), each share of BankFinancial common stock, $0.01 par value per share, issued and outstanding immediately prior to the Effective Time, was converted into the right to receive 0.480 of a share of common stock, no par value, of the Company (the “Company Common Stock”).

The foregoing description of the Merger and the Merger Agreement does not purport to be complete and is qualified in its entirety by reference to the Merger Agreement, attached as Exhibit 2.1 to the Company’s Current Report on Form 8-K filed on August 11, 2025 and incorporated herein by reference.

The issuance of shares of the Company Common Stock in connection with the Merger was registered under the Securities Act of 1933, as amended (the “Securities Act”), pursuant to a registration statement on Form S-4 (File No. 333-290507) filed by the Company with the Securities and Exchange Commission and which became effective on October 29, 2025 (the “Registration Statement”). The proxy statement/prospectus included in the Registration Statement contains additional information about the Merger Agreement and the transactions contemplated thereby.

Item 8.01 Other Events.

On December 31, 2025, the Company issued a press release announcing the completion of the Merger. A copy of the press release is filed as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits: