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 1,606,288 1,045,846 13,631,156 Jose Antonio Álvarez 177,731,329 3,014,196 1,054,258 13,631,156 Jin-Yong Cai 174,125,157 6,621,941 1,052,685 13,631,156 Jeffrey C. Campbell 176,879,147 3,873,093 1,047,543 13,631,156 Cheryl A. Francis 169,001,932 11,762,421 1,035,430 13,631,156 Jo Ann Jenkins 180,171,425 578,266 1,050,092 13,631,156 Adriana Karaboutis 177,781,035 2,967,949 1,050,799 13,631,156 Richard C. Notebaert 166,529,875 14,215,327 1,054,581 13,631,156 Gloria Santona 168,182,011 12,583,545 1,034,227 13,631,156 Sarah E. Smith 179,809,187 940,353 1,050,243 13,631,156 Byron O. Spruell 171,612,034 9,128,085 1,059,664 13,631,156 James G. Stavridis 178,830,425 1,909,168 1,060,190 13,631,156 2. An advisory vote to approve executive compensation. This advisory resolution was not approved. For Against Abstain Broker Non-Votes 69,888,299 110,798,636 1,112,848 13,631,156 3. The ratification of the appointment of Ernst & Young LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2026. This ordinary resolution was approved. For Against Abstain 174,935,923 19,452,290 1,042,726 4. The re-appointment of Ernst & Young Chartered Accountants as the Company’s statutory auditor under Irish law to hold office from the conclusion of the Annual Meeting until the conclusion of the next annual general meeting of shareholders. This ordinary resolution was approved. For Against Abstain 178,371,633 16,018,978 1,040,328 5. The authorization of the Company’s Board of Directors or the Audit Committee of the Company’s Board of Directors to determine the remuneration of Ernst & Young Chartered Accountants as the Company’s statutory auditor. This ordinary resolution was approved. For Against Abstain 188,174,624 6,222,678 1,033,637 6. The authorization of the Company’s Board of Directors to issue Class A Ordinary Shares under Irish law for a period expiring on the date which is 18 months from the date of the Annual Meeting. This ordinary resolution was approved. For Against Abstain 189,746,449 4,618,161 1,066,329 7. The authorization of the Company’s Board of Directors to opt-out of statutory pre-emption rights under Irish law for a period expiring on the date which is 18 months from the date of the Annual Meeting. This special resolution was approved. For Against Abstain 182,606,169 11,750,382 1,074,388 Item 8.01 Other Events. On June 26, 2026, the Company’s Board of Directors approved an increase to the Company’s share repurchase program, authorizing Aon to buy back an additional $7.5 billion of Class A Ordinary Shares. This is in addition to Aon’s existing share repurchase program, which had approximately $0.8 billion of remaining authorization as of March 31, 2026. The program does not obligate Aon to acquire any particular amount of shares. * * * * Item 9.01 Financial Statements and Exhibits. (d) Exhibits: Exhibit Number Description of Exhibit 10.1 Amendment to International Assignment Letter, dated June 26, 2026, between Aon Corporation and Greg Case. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document). SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Aon plc By: /s/ Darren Zeidel Name: Darren Zeidel Title: Executive Vice President, General Counsel and Company Secretary Date: July 1, 2026