Entry into a Material Definitive Agreement. On August 30, 2026, Aon plc, an Irish public limited company (the “Company” or “Aon”), Aon North America, Inc., a Delaware corporation (the “Acquirer”) and Cortlandt Acquisition Corp., a Delaware corporation and a direct, wholly owned subsidiary of Acquirer (“Merger Sub”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with USI Advantage Corp., a Delaware corporation (“USI”), and, solely in its capacity as the securityholder r…

CFO — Edmund Reese: The outgoing CFO transitions to a senior advisor role with an immediate internal interim successor, indicating an orderly succession rather than a sudden loss.

Results of Operations and Financial Condition. On July 29, 2026, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter ended June 30, 2026. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

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. * * * *

Gregory C. Case: The amendment extends the term of an existing assignment letter.

Results of Operations and Financial Condition. On May 1, 2026 , Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter ended March 31, 2026. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Results of Operations and Financial Condition. On January 30, 2026, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter and year ended December 31, 2025. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

President of Aon plc and Aon Corporation — Eric Andersen: Mr. Andersen is leaving the company with a separation agreement and severance benefits.

President and Chief Executive Officer — Gregory C. Case: The Employment Agreement extends Mr. Case's term and updates his compensation.

Results of Operations and Financial Condition. On October 31, 2025, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter ended September 30, 2025. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Director — Jo Ann Jenkins: The company appointed Jo Ann Jenkins as a new director and added her to the Audit Committee.

Senior Vice President, Global Controller and Chief Accounting Officer — David DeBrunner: Aon plc hired David DeBrunner as Senior Vice President, Global Controller and Chief Accounting Officer.

Results of Operations and Financial Condition. On July 25, 2025, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter ended June 30, 2025. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

The filing details amendments to an international assignment letter and the restatement of a compensation plan, which are administrative matters.

Results of Operations and Financial Condition. On April 25, 2025, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter ended March 31, 2025. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Director — Fulvio Conti: Fulvio Conti retired from the Board of Directors after more than 15 years.

President — Eric Andersen: Eric Andersen transitioned to a new role as Senior Advisor and ceased serving as President.

Chief Accounting Officer and Global Controller — Michael Neller: Michael Neller is transitioning to a new role as Deputy Global Chief People Officer, Total Rewards and Talent Development.

Results of Operations and Financial Condition. On January 31, 2025, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter and year ended December 31, 2024. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Results of Operations and Financial Condition. On October 25, 2024, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter ended September 30, 2024. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

of the Company’s Current Report on Form 8-K filed with the SEC on December 20, 2023, regarding the Company’s acquisition of NFP, which disclosure is incorporated herein by reference. In connection with the Company’s acquisition of NFP for an enterprise value of $13.0 billion and in consideration for his ownership of equity interests in NFP, Admiral Stavridis and his family trust were collectively issued 4,809 class A ordinary shares of the Company and $74,189. SIGNATURES Pursuant to the requi…

Director — James Stavridis: The company appointed James Stavridis as a new director and added him to the Finance Committee.

Results of Operations and Financial Condition. On July 26, 2024, Aon plc issued a press release (the “Press Release”) announcing its results of operations for the quarter ended June 30, 2024. A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Chief Financial Officer — Christa Davies: Christa Davies is retiring from her position as Executive Vice President and Chief Financial Officer with a transition period.

Chief Financial Officer — Edmund Reese: Aon plc hired Edmund Reese as the new Chief Financial Officer from Broadridge Financial Solutions, Inc.