Executive Change · Shareholder Vote

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): June 27, 2025     Aon plc (Exact name of registrant as specified in its charter)       Ireland   1-7933   98-1539969 (State or other jurisdiction of incorporation)   (Commission File Number)   (IRS Employer Identification No.)   15 George’s Quay , Dublin 2 , Ireland D02 VR98 (Address of principal executive offices) (Zip Code) Registrant’s telephone number, including area code: + 353 1 266 6000 Not Applicable (Former name or former address, if changed since last report)     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):   ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)   ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)   ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))   ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act:   Title of each class   Trading Symbol(s)   Name of each exchange on which registered Class A Ordinary Shares $0.01 nominal value   AON   New York Stock Exchange Guarantees of Aon plc’s 3.875% Senior Notes due 2025   AON25   New York Stock Exchange Guarantees of Aon plc’s 2.875% Senior Notes due 2026   AON26   New York Stock Exchange Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.85% Senior Notes due 2027   AON27   New York Stock Exchange Guarantees of Aon North America, Inc.’s 5.125% Senior Notes due 2027   AON27B   New York Stock Exchange Guarantees of Aon North America, Inc.’s 5.150% Senior Notes due 2029   AON29   New York Stock Exchange Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.05% Senior Notes due 2031   AON31   New York Stock Exchange Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.60% Senior Notes due 2031   AON31A   New York Stock Exchange Guarantees of Aon North America, Inc.’s 5.300% Senior Notes due 2031   AON31B   New York Stock Exchange Guarantee of Aon Corporation and Aon Global Holdings plc’s 5.00% Senior Notes due 2032   AON32   New York Stock Exchange Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.35% Senior Notes due 2033   AON33   New York Stock Exchange Guarantees of Aon North America, Inc.’s 5.450% Senior Notes due 2034   AON34   New York Stock Exchange Guarantees of Aon plc’s 4.250% Senior Notes due 2042   AON42   New York Stock Exchange Guarantees of Aon plc’s 4.45% Senior Notes due 2043   AON43   New York Stock Exchange Guarantees of Aon plc’s 4.600% Senior Notes due 2044   AON44   New York Stock Exchange Guarantees of Aon plc’s 4.750% Senior Notes due 2045   AON45   New York Stock Exchange Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.90% Senior Notes due 2051   AON51   New York Stock Exchange Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.90% Senior Notes due 2052   AON52   New York Stock Exchange Guarantees of Aon North America, Inc.’s 5.750% Senior Notes due 2054   AON54   New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company 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 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 27, 2025, Aon Corporation (“Aon Corporation”), an indirect, wholly owned subsidiary of Aon plc (together with its subsidiaries, “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, 2025, to expire on June 30, 2026. Amendment and Restatement of Aon plc 2011 Incentive Plan On June 27, 2025, the Company held its 2025 Annual General Meeting of Shareholders (the “Annual Meeting”) at which the Company’s shareholders approved the Aon plc 2011 Incentive Plan, as amended and restated (the “Amended Plan”). The Amended Plan increases by 3,800,000 the maximum number of Class A Ordinary Shares available for issuance thereunder. The Amended Plan also mandates a minimum vesting period of at least one year for all equity awards granted thereunder (subject to certain exceptions described in the Amended Plan). Further information regarding the Amended Plan was provided in the Company’s definitive proxy statement for the Annual Meeting filed with the Securities and Exchange Commission on April 28, 2025 (the “Proxy Statement”) in the section entitled “Proposal 8–Resolution to Approve the Aon plc 2011 Incentive Plan, As Amended and Restated”. The foregoing summaries are qualified in their entirety by reference to the Case Amendment and the Amended Plan, copies of which are attached as Exhibits 10.1 and 10.2, respectively, 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 on June 27, 2025. A total of 193,925,428 Class A Ordinary Shares, or 89.77% of the total shares entitled to vote, were represented at the Annual Meeting in person or by proxy. Shareholders voted on the following eight proposals at the Annual Meeting, all of which are described in the Proxy Statement, and cast their votes as described below:   1. The election of 12 nominees to serve as directors. All of the nominees were elected.   Nominee    For      Against      Abstain      Broker Non-Votes   Lester B. Knight      162,843,530        13,470,235        73,858        17,537,805   Gregory C. Case      175,184,226        1,149,339        54,058        17,537,805   Jose Antonio Álvarez      174,838,572        1,439,070        109,981        17,537,805   Jin-Yong Cai      173,844,128        2,468,438        75,057        17,537,805   Jeffrey C. Campbell      173,217,255        3,092,404        77,964        17,537,805   Cheryl A. Francis      167,846,227        8,343,311        198,085        17,537,805   Adriana Karaboutis      173,240,752        2,909,392        237,479        17,537,805   Richard C. Notebaert      163,198,345        13,119,735        69,543        17,537,805   Gloria Santona      165,532,594        10,650,336        204,693        17,537,805   Sarah E. Smith      175,835,501        451,004        101,118        17,537,805   Byron O. Spruell      173,926,837        2,381,609        79,177        17,537,805   James G. Stavridis      174,829,272        1,447,820        110,531        17,537,805   2. An advisory vote to approve executive compensation. This advisory resolution was approved.   For   Against   Abstain   Broker Non-Votes 156,384,747   19,184,418   818,458   17,537,805   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, 2025. This ordinary resolution was approved.   For   Against   Abstain 178,288,894   15,556,606   79,928   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 180,464,792   13,381,669   78,967   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 189,384,152   4,443,078   98,198   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 190,304,720   3,461,218   159,490   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 181,996,483   11,798,943   130,002   8. The approval of the Aon plc 2011 Incentive Plan, as amended and restated. This ordinary resolution was approved.   For   Against   Abstain   Broker Non-Votes 172,057,917   4,232,018   97,688   17,537,805 * * * * Item 9.01 Financial Statements and Exhibits. (d) Exhibits:   Exhibit Number    Description of Exhibit 10.1    Amendment to International Assignment Letter, dated June 27, 2025, between Aon Corporation and Greg Case. 10.2    Aon plc 2011 Incentive Plan, as Amended and Restated. 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 3, 2025