UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) 
of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): January 26, 2026

OLD NATIONAL BANCORP

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (773) 765-7675

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). 

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 1.01 Entry into a Material Definitive Agreement.

On January 29, 2026, Old National Bancorp (the “Company”) completed the issuance and sale (the “Offering”) of $450,000,000 aggregate principal amount of its 5.768% Fixed-to-Floating Rate Subordinated Notes due 2036 (the “Notes”). The Offering was completed pursuant to the Company’s registration statement on Form S-3 (File No. 333-272312) (including a base prospectus) filed with the Securities and Exchange Commission (the “SEC”) on June 1, 2023, as supplemented by the prospectus supplement dated January 26, 2026, and filed with the SEC on January 26, 2026 (the “Prospectus Supplement”).

In connection with the Offering, the Company entered into an Underwriting Agreement, dated January 26, 2026 (the “Underwriting Agreement”), with Keefe, Bruyette & Woods, Inc. and Morgan Stanley & Co. LLC, as representatives of the several underwriters listed on Schedule A attached thereto (collectively, the “Underwriters”). The Notes were sold at an underwriting discount of 0.75%, resulting in net proceeds to the Company of approximately $446.6 million before deducting expenses of the Offering. The Company intends to use the net proceeds from the Offering for general corporate purposes. The Underwriting Agreement contains customary representations, warranties and covenants and includes the terms and conditions for the sale of the Notes in the Offering, indemnification and contribution obligations and other terms and conditions customary in agreements of this type.

The Notes were issued under the Subordinated Indenture, dated as of January 29, 2026 (the “Base Indenture”), as supplemented by the First Supplemental Indenture, dated as of January 29, 2026 (the “First Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), between the Company and U.S. Bank Trust Company, National Association, as trustee (the “Trustee”).

From and including the date of issuance to, but excluding, February 15, 2031, or earlier redemption date, the Notes will bear interest at an initial fixed rate of 5.768% per annum, payable semi-annually in arrears on February 15 and August 15 of each year, commencing on August 15, 2026. From and including February 15, 2031 to, but excluding the maturity date, February 15, 2036, or earlier redemption date, the Notes will bear interest at a floating rate per annum equal to a benchmark rate, which is expected to be Three-Month Term SOFR (as defined in the First Supplemental Indenture), plus 220 basis points, payable quarterly in arrears on February 15, May 15, August 15 and November 15 of each year, commencing on May 15, 2031. Notwithstanding the foregoing, if the benchmark rate is less than zero, then the benchmark rate shall be deemed to be zero.

The Company may, at its option, redeem the Notes (i) in whole or in part beginning on the interest payment date of February 15, 2031, and on any interest payment date thereafter or (ii) in whole but not in part upon the occurrence of a “Tax Event,” a “Tier 2 Capital Event” or the Company becoming required to register as an investment company pursuant to the Investment Company Act of 1940, as amended. The redemption price for any redemption is 100% of the principal amount of the Notes, plus accrued and unpaid interest thereon to, but excluding, the date of redemption. Any redemption of the Notes will be subject to the receipt of the approval of the Board of Governors of the Federal Reserve System to the extent then required under applicable laws or regulations, including capital regulations.

There is no sinking fund for the Notes. The Notes rank junior to all of the Company’s existing and future senior indebtedness. In addition, the Notes are effectively subordinated to any secured indebtedness of the Company to the extent of the value of the assets securing such indebtedness. The Notes are structurally subordinated to all of the existing and future liabilities and obligations of the Company’s subsidiaries, including the deposit liabilities and claims of other creditors of the Company’s bank subsidiary, Old National Bank. The Notes are equal in right of payment with any of the Company’s existing and future subordinated indebtedness. The Notes are the obligations of the Company only and are not obligations of, and are not be guaranteed by, any of the Company’s subsidiaries.

The foregoing descriptions of the Underwriting Agreement and the Notes do not purport to be complete and are subject to, and qualified in their entirety by, the full text of (i) the Underwriting Agreement, (ii) the Base Indenture, (iii) the First Supplemental Indenture and (iv) the form of Note, each of which is attached hereto as an exhibit and is incorporated herein by reference.

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information in Item 1.01 above is incorporated by reference into this Item 2.03.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this Current Report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: January 29, 2026