AON: Leadership change · Other company developments

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. Amendment to International Assignment Letter On June 26, 2026, Aon Corporation (“Aon Corporation”), an indirect, wholly owned subsidiary of Aon plc (“Aon” or the “Company”), and Gregory C. Case entered into an amendment (the “Case Amendment”) to the international assignment letter agreement dated July 1, 2016 between Aon Corporation and Mr. Case (as amended, the “Case International Assignment Letter”). The Case Amendment extends the term of the Case International Assignment Letter, which was set to expire on June 30, 2026, to expire on June 30, 2027. The foregoing summary is qualified in its entirety by reference to the Case Amendment, a copy of which is attached as Exhibit 10.1 to this Current Report on Form 8-K and incorporated herein by reference. Item 5.07 Submission of Matters to a Vote of Security Holders. The Company held its Annual Meeting of Shareholders (the “Annual Meeting”) on June 26, 2026. A total of 195,430,939 Class A Ordinary Shares of Aon (“Class A Ordinary Shares”), or 91.51% of the total shares entitled to vote, were represented at the Annual Meeting in person or by proxy. Shareholders voted on the following seven proposals at the Annual Meeting, all of which are described in the Company’s definitive proxy statement for the Annual Meeting filed with the Securities and Exchange Commission on April 28, 2026 (the “Proxy Statement”), and cast their votes as described below: 1. The election of 13 nominees to serve as directors. All of the nominees were elected. Nominee For Against Abstain Broker Non-Votes Lester B. Knight 165,144,869 15,620,855 1,034,059 13,631,156 Gregory C. Case 179,147,649 1,606,28