Additional Proxy Soliciting Materials (Form DEFA14A)

Your Vote Counts! Smartphone users Point your camera here and vote without entering a control number For complete information and to vote, visit www.ProxyVote.com Control # V88330-P44846 OLD NATIONAL BANCORP You invested in OLD NATIONAL BANCORP and it's time to vote! You have the right to vote on proposals being presented at Old National Bancorp's 2026 Annual Meeting of Shareholders. This is an important notice regarding the availability of proxy materials for the 2026 Annual Meeting of Shareholders to be held on May 13, 2026. Vote Virtually During the Meeting* May 13, 2026 10:00 AM Central Time Virtually at: www.virtualshareholdermeeting.com/ONB2026 *Please check the meeting materials for any special requirements for meeting attendance. Get informed before you vote View Old National Bancorp's Annual Report on Form 10-K, Notice of 2026 Annual Meeting of Shareholders and Proxy Statement online OR you can receive a free paper or email copy of the material(s) by requesting them prior to April 29, 2026. If you would like to request a copy of the material(s) for this and/or future shareholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to [email protected]. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. 2026 Annual Meeting of Shareholders Vote by May 12, 2026 11:59 p.m. Eastern Time. For shares held in an employee benefit plan, vote by May 8, 2026 11:59 p.m. Eastern Time. OLD NATIONAL BANCORP ATTN: CORPORATE SECRETARY P.O. BOX 718 EVANSVILLE, IN 47705

Vote at www.ProxyVote.com Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings". Voting Items Board Recommends V88331-P44846 THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming 2026 Annual Meeting of Shareholders. Please follow the instructions on the reverse side to vote on these important matters. 1. Election of Directors For Nominees: 01) Barbara A. Boigegrain 02) Thomas L. Brown 03) Kathryn J. Hayley 04) Peter J. Henseler 05) Daniel S. Hermann 06) Ryan C. Kitchell 07) Daniel C. Reardon 08) James C. Ryan, III 09) Thomas E. Salmon 10) Michael J. Small 11) Derrick J. Stewart 12) Katherine E. White 2. Approval of a non-binding advisory proposal on the compensation of the Company's named executive officers. For 3. Ratification of the appointment of Deloitte & Touche LLP as the independent registered public accounting firm of the Company for the year ending December 31, 2026. For 4. Approval of the Company's 2026 Equity Compensation Plan. For NOTE: In their discretion, the proxies named in the proxy card are authorized to vote upon such other matters as may properly come before Old National Bancorp's 2026 Annual Meeting of Shareholders, and at any adjournment or postponement thereof.