
Aon plc (Exact name of registrant as specified in its charter) +3531266 6000(Registrant’s Telephone Number, including area code) Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule405 of the Securities Act.Yes☒No☐ Indicate by check mark if the registrant is not required to file reports pursuant to Section13 or Section15(d) of the Exchange Act. Yes☐No☒ Indicate by check mark whether the registrant (1)has filed all reports required to be filed by Section13 or 15(d) of the Securities Exchange Act of 1934 during thepreceding 12months (or for such shorter period that the registrant was required to file such reports), and (2)has been subject to such filing requirements for the past90days.Yes☒No☐ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule405 ofRegulationS-T (§232.405 of this chapter) during the preceding 12months (or for such shorter period that the registrant was required to submit such files).Yes☒No☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerginggrowth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule12b-2 of theExchange Act. Large accelerated filer☒Accelerated filer☐Non-accelerated filer☐Smaller reporting company☐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 orrevised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐ Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control overfinancial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filingreflect the correction of an error to previously issued financial statements.☐ Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by anyof the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule12b-2 of the Exchange Act). Yes☐No☒ DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s proxy statement for its 2025 Annual General Meeting of Shareholders are incorporated by reference in this report in response to PartIII, Information Concerning Forward-Looking Statements This report contains certain statements related to future results, or states our intentions, beliefs, and expectations or predictions forthe future, all of which are forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995,Section 27A of the Securities Act of 1933, as amended, (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934,as amended (the “Exchange Act”). Forward-looking statements represent management’s expectations or forecasts of future events.These statements include statements about our plans, objectives, strategies, financial performance and outlook, trends, prospects orother future events and involve known and unknown risks that are difficult to predict. Forward-looking statements are typicallyidentified by words such as “anticipate,” “believe,” “estimate,” “expect,” “forecast,” “project,” “positioned,” “intend,” “plan,”“probably,” “potential,” “looking forward,” “continue,” and other similar terms, and future or conditional tense verbs like “could,”“may,” “might,” “should,” “will,” and “would.” You can also identify forward-looking statements by the fact that they do not relatestrictly to historical or current facts. For example, we may use forward-looking statements when addressing topics such as: market andindustry conditions, including competitive and pricing trends; changes in our business strategies and methods of generating revenue;the development and performance of our services and products; changes in the composition or level of our revenues; our cost structureand the outcome of cost-saving or restructuring initiatives, including the impacts of the Accelerating Aon United Program; outcome ofcontingencies; dividend policy; the expected impact of acquisitions, dispositions, and other significant transactions or the terminationthereof; litigation and regulatory matters; pension obligations; cash flow and liquidity; expected effective tax rate; expected foreigncurrency translation imp