Aon: 2026 AGM Voting Results

(State or other jurisdiction of incorporation)

(Commission File Number)

(IRS Employer Identification No.)

(Address of principal executive offices) (Zip Code)

(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 Corporation and Aon Global

Holdings plc's 2.85% Senior Notes due 2027 Guarantees of Aon North America, Inc.'s 5.125% Senior Notes due 2027

Guarantees of Aon North America, Inc.'s 5.150% Senior Notes due 2029

Guarantees of Aon Corporation and Aon Global Holdings plc's 2.05% Senior Notes due 2031 Guarantees of Aon Corporation and Aon Global Holdings plc's 2.60% Senior Notes due 2031 Guarantees of Aon North America, Inc.'s 5.300% Senior Notes due 2031

Guarantee of Aon Corporation and Aon Global Holdings plc's 5.00% Senior Notes due 2032 Guarantees of Aon Corporation and Aon Global Holdings plc's 5.35% Senior Notes due 2033 Guarantees of Aon North America, Inc.'s 5.450% Senior Notes due 2034

Guarantees of Aon plc's 4.250% Senior Notes due 2042

Guarantees of Aon plc's 4.45% Senior Notes due 2043

AON27 New York Stock Exchange

AON27B New York Stock Exchange

AON29 New York Stock Exchange

AON31 New York Stock Exchange

AON31A New York Stock Exchange

AON31B New York Stock Exchange

AON32 New York Stock Exchange

AON33 New York Stock Exchange

AON34 New York Stock Exchange

AON42 New York Stock Exchange

AON43 New York Stock Exchange

Guarantees of Aon plc's 4.600% Senior Notes due 2044

Guarantees of Aon plc's 4.750% Senior Notes due 2045

Guarantees of Aon Corporation and Aon Global Holdings plc's 2.90% Senior Notes due 2051 Guarantees of Aon Corporation and Aon Global Holdings plc's 3.90% Senior Notes due 2052 Guarantees of Aon North America, Inc.'s 5.750% Senior Notes due 2054

AON44 New York Stock Exchange

AON45 New York Stock Exchange

AON51 New York Stock Exchange

AON52 New York Stock Exchange

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. ☐

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.

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.

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.

* * * *

(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).

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.

By: /s/ Darren Zeidel Name: Darren Zeidel

Title: Executive Vice President, General Counsel and

Company Secretary Date: July 1, 2026

Gregory Case Aon Corporation United States

June 26, 2026

Dear Greg,

This letter serves to amend your international assignment letter effective July 1, 2016, governing the terms of your international assignment from Chicago, Illinois to Aon Global Limited in London, England (your "International Assignment Letter").

Pursuant to this letter, the term of your international assignment shall be extended an additional one year, through June 30, 2027.

Except as otherwise expressly modified herein, the terms of the International Assignment Letter, and your acknowledgment and acceptance thereof, shall continue in full force and effect.

Please confirm acceptance of the terms and conditions of this letter by signing below and returning a copy of the signed letter to me. Sincerely,

/s/ Lisa Stevens

Lisa Stevens

Chief Administrative Officer Acknowledged and Agreed:

/s/ Gregory Case Gregory Case