Aon 10-K/A 2023-12-31

Table of Contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM

10-K/A

(Amendment No. 1)

☒		ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2023

☐		TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from ___________ to ____________    

Commission File Number:

1-7933

Aon plc

(Exact name of registrant as specified in its charter)

Ireland		98-1539969
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

Metropolitan Building, James Joyce Street, Dublin 1, Ireland D01 K0Y8

(Address of Principal Executive Offices) (Zip Code)

+353 1 266 6000

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class		Trading Symbol		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 3.50% Senior Notes due 2024		AON24		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 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 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 plc’s 4.25% 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 4.60% Senior Notes due 2044		AON44		New York Stock Exchange
Guarantees of Aon plc’s 4.75% 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 5.125% 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 North America, Inc.’s 5.300% Senior Notes due 2031		AON31B		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 North America, Inc.’s 5.750% Senior Notes due 2054		AON54		New York Stock Exchange

Securities registered pursuant to Section 12 (g) of the Act: None.

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

Yes ☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

Yes ☐ No  ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (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 past 90 days. 

Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation

S-T

(§ 232.405 of this chapter) during the preceding 12 months (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 emerging growth company. See the definitions of “large accelerated filer”, “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule

12b-2

of the Exchange 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 or revised 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 over financial 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 filing reflect 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 any of 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 Rule

12b-2

of the Act).

Yes ☐ No ☒

As of June 30, 2023, the aggregate market value of the registrant’s Class A Ordinary Shares held by

non-affiliates

of the registrant was $70,135,237,097 based on the closing sales price as reported on the New York Stock Exchange — Composite Transaction Listing.

Number of the registrant’s Class A Ordinary Shares of Aon plc, $0.01 nominal value, outstanding as o

f April 12, 202

4: 198,506,718.

DOCUMENTS INCORPORATED BY REFERENCE

None.

EXPLANATORY NOTE

This Amendment No. 1 on Form

10-K/A

(this “Amendment”) amends our Annual Report on Form

10-K

for the fiscal year ended December 31, 2023, originally filed with the Securities and Exchange Commission (the “SEC”) on February 16, 2024 (the “Original Filing”). The Original Filing omitted Part III, Items 10 (Directors, Executive Officers and Corporate Governance), 11 (Executive Compensation), 12 (Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters), 13 (Certain Relationships and Related Transactions, and Director Independence) and 14 (Principal Accountant Fees and Services) in reliance on General Instruction G(3) to Form

10-K,

which provides that such information may be either incorporated by reference from the registrant’s definitive proxy statement or included in an amendment to Form 10-K, in either case filed with the Securities and Exchange Commission (the “SEC”) not later than 120 days after the end of the fiscal year. We are filing this Amendment solely to amend Part III, Items 10, 11, 12, 13 and 14 of the Original Filing to include the information required by such Items.

In addition, in connection with the filing of this Amendment and pursuant to the rules of the SEC, we are including with this Amendment new certifications of our principal executive officer and principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. Item 15 of Part IV has also been amended to reflect the filing of these new certifications.

Except as described above, no other changes have been made to the Original Filing. The Original Filing continues to speak as of the date of the Original Filing, and we have not updated the disclosures contained therein to reflect any events which occurred at a date subsequent to the filing of the Original Filing.

Unless otherwise indicated or unless the context requires otherwise, all references in this Amendment to “we,” “us,” “our,” “our Company” or “the Company” refer to Aon plc, an Irish public limited company, together with its consolidated subsidiaries.

As previously announced, on December 19, 2023, Aon entered into a definitive agreement with Randolph Acquisition Corp., a Delaware corporation and an indirect, wholly owned subsidiary of Aon (the “Acquirer”), Randolph Merger Sub LLC, a Delaware limited liability company and a direct, wholly owned subsidiary of the Acquirer, NFP Intermediate Holdings A Corp., a Delaware corporation (“NFP”), and NFP Parent Co, LLC, a Delaware limited liability company, pursuant to which the Acquirer will acquire NFP.

i

Information Concerning Forward-Looking Statements

This Amendment contains certain statements related to future results, or states our intentions, beliefs, and expectations or predictions for the 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 or other future events and involve known and unknown risks that are difficult to predict. Forward-looking statements are typically identified by words such as “anticipate,” “believe,” “estimate,” “expect,” “forecast,” “project,” “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 relate strictly to historical or current facts. For example, we may use forward-looking statements when addressing topics such as: market and industry 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 structure and the outcome of cost-saving or restructuring initiatives, including the impacts of the Accelerating Aon United Program; the pending acquisition of NFP; the outcome of contingencies; dividend policy; the expected impact of acquisitions, dispositions, and other significant transactions or the termination thereof; litigation and regulatory matters; pension obligations; cash flow and liquidity; expected effective tax rate; expected foreign currency translation impacts; potential changes in laws or future actions by regulators; and the impact of changes in accounting rules. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from either historical or anticipated results depending on a variety of factors. Potential factors, which may be revised or supplemented in subsequent reports filed or furnished with the SEC, that could impact results include:

	•		changes in the competitive environment, due to macroeconomic conditions (including impacts from instability in the banking or commercial real estate sectors) or otherwise, or damage to our reputation;

	•		fluctuations in currency exchange, interest, or inflation rates that could impact our financial condition or results;

	•		changes in global equity and fixed income markets that could affect the return on invested assets;

	•		changes in the funded status of our various defined benefit pension plans and the impact of any increased pension funding resulting from those changes;

	•		the level of our debt and the terms thereof reducing our flexibility or increasing borrowing costs;

	•		rating agency actions that could limit our access to capital and our competitive position;

	•		our global tax rate being subject to a variety of different factors, including the adoption and implementation in the European Union, the United States, the United Kingdom, or other countries of the Organization for Economic Co-operation and Development tax proposals or other pending proposals in those and other countries, which could create volatility in that tax rate;

	•		changes in our accounting estimates and assumptions on our financial statements;

	•		limits on our subsidiaries’ ability to pay dividends or otherwise make payments to their respective parent entities;

	•		the impact of legal proceedings and other contingencies, including those arising from acquisition or disposition transactions, errors and omissions and other claims against us (including proceedings and contingencies relating to transactions for which capital was arranged by Vesttoo Ltd.);

ii

	•		the impact of, and potential challenges in complying with, laws and regulations of the jurisdictions in which we operate, particularly given the global nature of operations and the possibility of differing or conflicting laws and regulations, or the application or interpretation thereof, across such jurisdictions;

	•		the impact of any regulatory investigations brought in Ireland, the United Kingdom, the United States, and other countries;

	•		failure to protect intellectual property rights or allegations that we have infringed on the intellectual property rights of others;

	•		general economic and political conditions in the countries in which we do business around the world;

	•		the failure to retain, attract and develop experienced and qualified personnel, whether as a result of the pending acquisition of NFP or otherwise;

	•		international risks associated with our global operations, including impacts from military conflicts or political instability, such as the ongoing Russian war in Ukraine and the Israel-Hamas conflict;

	•		the effects of natural or man-made disasters, including the effects of health pandemics and the impacts of climate-related events;

	•		any system or network disruption or breach resulting in operational interruption or improper disclosure of confidential, personal, or proprietary data, and resulting liabilities or damage to our reputation;

	•		our ability to develop, implement, update, and enhance new technology;

	•		the actions taken by third parties that perform aspects of our business operations and client services;

	•		the extent to which we are exposed to certain risks, including lawsuits, related to our actions we may take in being responsible for making decisions on behalf of clients in our investment businesses or in other advisory services that we currently provide, or will provide in the future;

	•		our ability to continue, and the costs and risks associated with growing, developing and integrating acquired business, and entering into new lines of business or products;

	•		our ability to secure regulatory approval and complete transactions, including the pending acquisition of NFP, and the costs and risks associated with the failure to consummate proposed transactions;

	•		changes in commercial property and casualty markets, commercial premium rates or methods of compensation;

	•		our ability to develop and implement innovative growth strategies and initiatives intended to yield cost savings (including the Accelerating Aon United Program) and the ability to achieve such growth or cost savings;

	•		the effects of Irish law on our operating flexibility and the enforcement of judgments against us;

	•		adverse effects on the market price of Aon’s securities and/or operating results for any reason, including, without limitation, because of a failure to consummate the pending acquisition of NFP or the failure to realize the expected benefits of the pending acquisition of NFP (including anticipated revenue and growth synergies) in the expected timeframe, or at all;

	•		significant transaction and integration costs or difficulties in connection with the pending acquisition of NFP or unknown or inestimable liabilities; and

iii

	•		potentia l impact of the consummation of the pending acquisition of NFP on relationships, including with suppliers, customers, employees and regulators.

Any or all of our forward-looking statements may turn out to be inaccurate, and there are no guarantees about our performance. The factors identified above are not exhaustive. Aon and its subsidiaries operate in a dynamic business environment in which new risks may emerge frequently. Accordingly, readers should not place undue reliance on forward-looking statements, which speak only as of the dates on which they are made. We are under no (and expressly disclaim any) obligation to update or alter any forward-looking statement that we may make from time to time, whether as a result of new information, future events, or otherwise. Further information about factors that could materially affect Aon, including our results of operations and financial condition, is contained in the “Risk Factors” section in Part I, Item 1A of the Original Filing.

iv

Aon plc

INDEX TO FORM

10-K/A

For the Year Ended December 31, 2023

PART III
ITEM 10. Directors, Executive Officers and Corporate Governance.			1
ITEM 11. Executive Compensation.			9
ITEM 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.			53
ITEM 13. Certain Relationships and Related Transactions, and Director Independence.			56
ITEM 14. Principal Accounting Fees and Services.			57
PART IV
ITEM 15. Exhibits.			58
SIGNATURES			59
Appendix A - Reconciliation of Non-GAAP Measures			A-1

v

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PART III

Executive Officers

Information relating to Aon’s executive officers is set forth in Part I of the Original Filing and is incorporated herein by reference. On April 1, 2024, Ms. Davies notified the Company of her intention to retire from the position of Chief Financial Officer. Ms. Davies is expected to serve as Chief Financial Officer into the third quarter of 2024 and is thereafter expected to serve as a senior advisor for a transition period into 2025.

Directors

The term of each director expires at the next annual general meeting of shareholders (the “Annual Meeting”), and each director will continue in office until the election of his or her respective successor or until his or her earlier resignation or removal in accordance with the Company’s articles of association (the “Articles”) or the Irish Companies Act 2014, as amended. Consistent with the terms of the Articles, the Company’s board of directors (the “Board”) currently is authorized to have up to 21 directors, and the number of directors was most recently set by the Board at 13. Carolyn Y. Woo has decided to retire from the Board effective at the next Annual Meeting. Following Dr. Woo’s retirement, the Board expects to reduce the size of the Board to 12.

		Name		Age		Director Since		Current Committee Membership		Other Boards†
		Lester B. Knight, Chair*		65		1999		Executive Committee - Chair Governance/Nominating Committee - Chair Inclusion & Wellbeing Sub-Committee		—
		Gregory C. Case, CEO		61		2005		Executive Committee Inclusion & Wellbeing Sub-Committee		1
		Jose Antonio Álvarez*		63		2024		Audit Committee		2
		Jin-Yong Cai*		64		2016		Finance Committee Organization and Compensation Committee		2
		Jeffrey C. Campbell*		63		2018		Audit Committee - Chair Executive Committee Organization and Compensation Committee		1
		Fulvio Conti*		76		2008		Audit Committee Executive Committee Finance Committee - Chair Governance/Nominating Committee		1
		Cheryl A. Francis*		70		2010		Finance Committee Governance/Nominating Committee Inclusion & Wellbeing Sub-Committee - Chair Organization and Compensation Committee		2
		Adriana Karaboutis*		61		2022		Audit Committee		2
		Richard C. Notebaert*		76		1998		Executive Committee Finance Committee Governance/Nominating Committee Inclusion & Wellbeing Sub-Committee Organization and Compensation Committee - Chair		—

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		Name		Age		Director Since		Current Committee Membership		Other Boards†
		Gloria Santona*		73		2004		Audit Committee Governance/Nominating Committee Inclusion & Wellbeing Sub-Committee		—
		Sarah E. Smith*		65		2023		Finance Committee		1
		Byron O. Spruell*		59		2020		Audit Committee Inclusion & Wellbeing Sub-Committee Organization and Compensation Committee		—
		Carolyn Y. Woo††*		68		1998		Audit Committee Organization and Compensation Committee		—

•   Independent Director

†   Number of other public company directorships or listed business development company trusteeships

†† Dr. Woo is retiring effective at the Annual Meeting

Aon values a number of attributes and criteria when identifying nominees to serve as a director, including professional background, expertise, reputation for integrity, business, financial and management experience, leadership capabilities, and diversity. We believe all of the nominees are individuals with a reputation for integrity, demonstrate strong leadership capabilities, and are able to work collaboratively to make contributions to the Board and management. Biographical information about the directors and the experience, qualifications, attributes, and skills considered by our Governance/Nominating Committee and the Board in determining that the directors should serve as a director appears below.

Lester B. Knight Director since 1999 Age: 65 Committees: • Executive Committee (Chair) • Governance/Nominating Committee (Chair) • Inclusion & Wellbeing Sub-Committee		Mr. Knight is a Founding Partner of RoundTable Healthcare Partners and the former Vice Chairman and director of Cardinal Health, Inc., a diversified healthcare service company. Mr. Knight was Chairman of the Board and Chief Executive Officer of Allegiance Corporation from 1996 until February 1999, and had been with Baxter International, Inc. from 1981 until 1996, where he served as Corporate Vice President from 1990, Executive Vice President from 1992 and as a director from 1995. Mr. Knight became Chairman of the Board of Directors of Aon in August 2008. He is a life director of NorthShore University Health System and Junior Achievement of Chicago, a life Trustee of Northwestern University and a member of the Civic Committee of The Commercial Club of Chicago. Skills & Qualifications: Mr. Knight’s experience as the founder of a private equity firm focused on investing in the healthcare industry, his executive background at several leading healthcare companies, and his financial and investment expertise provides the Board with executive leadership and oversight experience. In addition, his role in chairing our Governance/Nominating Committee and his previous leadership and Board experience at other public companies position him to effectively lead the Board. Mr. Knight provides valuable perspectives with his broad experience in corporate governance, strategic transactions, business transformation and growth and oversight.

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Gregory C. Case Director since 2005 Age: 61 Committees: • Executive Committee • Inclusion & Wellbeing Sub-Committee		Mr. Case has served as Chief Executive Officer and a director of Aon since April 2005. Mr. Case served as Aon’s President from 2005 to 2018. Prior to joining Aon, Mr. Case was with McKinsey & Company, the global management consulting firm, for 17 years where he served on the governing Shareholders’ Council and as head of the Global Insurance and Financial Services Practice. Prior to joining McKinsey, Mr. Case was with the investment banking firm of Piper, Jaffray and Hopwood and the Federal Reserve Bank of Kansas City. Mr. Case is a director of Discover Financial Services. Skills & Qualifications: As Chief Executive Officer of Aon, Mr. Case brings to the Board his day-to-day experiences leading Aon’s 50,000 colleagues serving clients across Commercial Risk, Reinsurance, Health, and Wealth solution lines, and his intimate knowledge of Aon’s business and operations. Mr. Case’s background as a management consultant, including in the global insurance and financial services areas, brings critical industry and business development knowledge to the Board. His extensive and specific knowledge of Aon and its businesses enables him to keep the Board apprised of the most significant developments impacting the Company and to guide the Board’s discussion and review of the Company’s strategy.
Jose Antonio Álvarez Director since 2024 Age: 64 Committees: • Audit Committee		Mr. Álvarez is the former Chief Executive Officer of Banco Santander, S.A., a Spanish multinational financial services company, and currently serves as Vice Chair and a non-executive director of Santander. Mr. Álvarez first joined Santander in 2002 and served as Executive Vice President and Chief Financial Officer from 2004 to 2014. In 2015, Mr. Álvarez was appointed Chief Executive Officer of Santander and served in that role until his retirement in 2022. Mr. Álvarez previously served as a member of the supervisory boards of Santander Consumer Bank AG, Santander Consumer Holding GmbH and Santander Bank Polska, S.A., and as a director of SAM Investments Holdings Limited, Santander Consumer Finance, S.A. and Santander Holdings USA, Inc. In addition, Mr. Álvarez previously served as a board member of Bolsas y Mercados Españoles, S.A. Mr. Álvarez is currently Vice Chair and a non-executive director of Banco Santander (Brasil) S.A. Skills & Qualifications: Mr. Álvarez’s experience as former Chief Executive Officer, and previously Chief Financial Officer, of a multinational financial services company provides the Board with deep knowledge and expertise in international finance, and unique insights into emerging and global markets and investments. In addition, as a member and prior member of the board of directors of several international companies that invest globally, Mr. Álvarez brings substantive expertise in business strategy in international markets, as well as business transformation and risk management, to the Board. Mr. Álvarez’s extensive financial background and experience has led the Board to determine that he is an “audit committee financial expert” as defined by the SEC.

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Jin-Yong Cai Director since 2016 Age: 64 Committees: • Finance Committee • Organization and Compensation Committee		Mr. Cai is a Partner at Global Infrastructure Partners, a global private equity investment firm. Prior to his current position, Mr. Cai was a Partner at TPG Capital, L.P., a global private equity investment firm. From 2012 to 2016, Mr. Cai was the Chief Executive Officer of the International Finance Corporation, a member of the World Bank Group and the largest global development institution focused on private sector development. Before the International Finance Corporation, Mr. Cai worked in the financial services industry for nearly two decades, including 12 years with Goldman Sachs Group, as a Partner and its top executive in China. He began his career at the World Bank Group. Mr. Cai is a director of PetroChina Company Limited and Syngenta Group. Skills & Qualifications: Mr. Cai’s experience in global finance and international business, particularly in the Asia-Pacific region, enhances the Board’s global perspectives. Mr. Cai’s increased level of financial literacy and extensive background with international finance and global management, including areas relating to investment banking and private equity, provide valuable perspective and knowledge relating to financial risk and risks related to the Company’s international activities and growth strategies.
Jeffrey C. Campbell Director since 2018 Age: 63 Committees: • Audit Committee (Chair) • Executive Committee • Organization and Compensation Committee		Mr. Campbell served as Chief Financial Officer of American Express Company, from July 2013 until August 2023, and as Vice Chairman from April 2021 to March 2024. From 2004 to 2013, Mr. Campbell served as Executive Vice President and Chief Financial Officer at McKesson Corporation, a leading healthcare services, information technology and distribution company. Prior to his time at McKesson, Mr. Campbell spent 13 years at AMR Corporation and its principal subsidiary, American Airlines, ultimately becoming its Chief Financial Officer in 2002. He serves as the Lead Director and Chair of the Audit Committee of Hexcel Corporation. Mr. Campbell is also a board member of The Julliard School and the Lincoln Center for the Performing Arts, and is the Chair of the Lincoln Center Corporate Fund. Skills & Qualifications: Having served as chief financial officer of three multinational, publicly traded companies, Mr. Campbell adds financial expertise and risk management leadership to the Board. His significant business experience, deep financial acumen and leadership in the development of diverse talent provide the Board and its committees with valuable management perspective. He also brings to the Board substantial experience in the areas of compliance, risk oversight, corporate finance and strategy, as well as knowledge and experience relating to the financial services sector. This experience has also led the Board to determine that Mr. Campbell is an “audit committee financial expert” as defined by the SEC.
Fulvio Conti Director since 2008 Age: 76 Committees: • Finance Committee (Chair) • Audit Committee • Executive Committee • Governance/Nominating Committee		Mr. Conti served as Chairman of TIM SpA, a leader in the telecommunications market in Italy, from May 2018 to September 2019. He served as Chief Executive Officer and General Manager of Enel SpA, Italy’s largest power company, from May 2005 to May 2014. From 1999 until 2005, he served as Chief Financial Officer of Enel. Mr. Conti has a financial and industrial career spanning over 40 years. Prior to joining Enel, SpA, he was the Chief Financial Officer and general manager of Ferrovie dello Stato SpA and Telecom Italia SpA. From 1970 to 1990, he held many roles at Mobil Oil Corporation in Italy and other countries, including as Chief Financial Officer of Mobil Oil Europe and Chief Operating Officer of Mobil Plastics Europe. From 1991 to 1995, Mr. Conti was Chief Financial Officer of Montedison-Compart, SpA. Mr. Conti currently serves as Chairman of Innova Italy Srl, Chairman of SGI SpA (Societa’ Gasdotti ltalia SpA), and chairman of Fondo Italiano Efficienza Energetica (FIEE SGR SpA). In addition, Mr. Conti serves as a director of Take Off SpA. Mr. Conti previously served as a non-executive director of Barclays plc, RCS Mediagroup and director of the Italian Institute of Technology as well as Unidad Editorial SA. In 2009, he was appointed “Cavaliere del Lavoro” of the Italian Republic and in December of that year he became “Officier de la Légion d’Honneur” of the French Republic. Skills & Qualifications: Mr. Conti’s background as a chief executive officer and chief financial officer of a large international energy company, his familiarity with international business and finance activities, particularly in the European Union, and his global financial and management experience bring financial expertise and global leadership to the Board. In addition, Mr. Conti’s background as a chief financial officer of a multinational utility provides a knowledgeable resource on matters relating to financial reporting and treasury. His experience has also led the Board to determine that Mr. Conti is an “audit committee financial expert” as defined by the SEC.

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Cheryl A. Francis Director since 2010 Age: 70 Committees: • Inclusion & Wellbeing Sub-Committee (Chair) • Finance Committee • Governance/Nominating Committee • Organization and Compensation Committee		Ms. Francis served as Executive Vice President and Chief Financial Officer of R.R. Donnelley & Sons Co., a publicly traded print media company, from 1995 until 2000. Since 2000, Ms. Francis has served as a business consultant and, since August 2008, as Co-Chair of the Corporate Leadership Center. From 2002 until 2008, she served as Vice Chairman of the Corporate Leadership Center. Prior to her role at R.R. Donnelley, Ms. Francis served on the management team of FMC Corporation and its subsidiary, FMC Gold, including serving as Chief Financial Officer of FMC Gold from 1987 through 1991, and Treasurer of FMC Corporation from 1993 through 1995. She was also an adjunct professor for the University of Chicago Graduate School of Business from 1991 through 1993. Ms. Francis currently serves as a director of HNI Corporation and Morningstar, Inc., and previously served as a director of Hewitt Associates, Inc. from 2002 until the Company’s acquisition of Hewitt Associates, Inc. in 2010. Skills & Qualifications: Ms. Francis’s background as a chief financial officer of a large publicly traded company provides the Board with an increased level of financial literacy. In addition, her role as a Board member of other public companies provides valuable perspective on matters of risk oversight, corporate governance and strategy. As Co-Founder of the Corporate Leadership Center’s CEO Perspectives and Leading Women Executives, Ms. Francis is a leading voice on inclusion and leadership development.

Adriana Karaboutis Director since 2022 Age: 61 Committees: • Audit Committee		From 2017 to August 2023, Ms. Karaboutis served as Chief Information and Digital Officer of National Grid PLC, one of the world’s largest public utility companies focused on transmitting and distributing electricity and gas in the UK and northeast US. She previously served as Executive Vice President, Technology, Business Solutions and Corporate Affairs at Biogen Inc., a global biotechnology company, from September 2014 to March 2017. In that role, she introduced leading digital and data science capabilities that unlocked value across the drug discovery, development, and delivery processes. From December 2015, she also oversaw global public affairs, government affairs, public policy and patient advocacy. From March 2010 to September 2014, Ms. Karaboutis was Vice President and Global Chief Information Officer of Dell, Inc., a global technology company. Ms. Karaboutis previously spent more than 20 years at General Motors Company and Ford Motor Company in various international leadership positions, including global production planning, computer-integrated manufacturing, supply chain operations and information technology. Ms. Karaboutis serves as a director of Perrigo Company plc, a global over-the-counter consumer goods and pharmaceutical company, and Savills plc, a British real estate services company. She previously served on the boards of directors of Aspen Technology, Advance Auto Parts and Blue Cross Blue Shield of Massachusetts. Skills & Qualifications: Ms. Karaboutis’ background as a chief information officer for a public utility company and a global technology company provides the Board with valuable insight and experience in technology, cybersecurity, data privacy and data security matters. In addition, Ms. Karaboutis’ experience in developing and delivering digital solutions and data science capabilities enhances the Board’s perspective in innovative strategies. Ms. Karaboutis’ role as a current and former board member of multiple public companies provides valuable perspective on matters of risk oversight, corporate governance and executive management.

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Richard C. Notebaert Director since 1998 Age: 76 Committees: • Organization and Compensation Committee (Chair) • Executive Committee • Finance Committee • Governance/Nominating Committee • Inclusion & Wellbeing Sub-Committee		From June 2002 until August 2007, Mr. Notebaert served as Chairman and Chief Executive Officer of Qwest Communications International Inc., a leading provider of broadband Internet-based data, voice and image communications. He previously served as President and Chief Executive Officer of Tellabs, Inc., which designs and markets equipment to providers of telecommunications services worldwide, from August 2000 to June 2002, and as a director of Tellabs from April 2000 to June 2002. He served as Chairman of the Board and Chief Executive Officer of Ameritech Corporation, a full-service communications company, from 1994 until 1999. Mr. Notebaert first joined Ameritech Communications in 1983 and served in significant positions within the Ameritech organization before his election as Vice Chairman in January 1993, President and Chief Operating Officer in June 1993 and President and Chief Executive Officer in January 1994. Mr. Notebaert is a Trustee Emeritus of the Board of Trustees of the University of Notre Dame. Mr. Notebaert previously served as a director of American Electric Power and Cardinal Health, Inc., and as Chairman of the Board of Trustees of the University of Notre Dame. Skills & Qualifications: Mr. Notebaert’s background as a chairman and chief executive officer of several large international communications companies provides the Board with substantial management expertise, including in the areas of global operations, technology and innovation and strategic planning. In addition, Mr. Notebaert’s executive and board leadership experience provides valuable perspectives on matters of risk oversight, corporate governance and executive management.

Gloria Santona Director since 2004 Age: 73 Committees: • Audit Committee • Governance/Nominating Committee • Inclusion & Wellbeing Sub-Committee		Ms. Santona served as Of Counsel at Baker McKenzie, an international law firm, from 2018 to 2022. Prior to Baker McKenzie, Ms. Santona served as Executive Vice President, General Counsel and Secretary of McDonald’s Corporation from 2001 to 2017 when she retired. After joining McDonald’s in 1977, Ms. Santona held positions of increasing responsibility in the legal department, serving as U.S. General Counsel from December 1999 to June 2001 and corporate General Counsel from 2001 to 2017. She is a member of the Board of Trustees of Rush University Medical Center and former member of the Board of Directors of the American Society of Corporate Secretaries, the Association of Corporate Counsel and the Minority Corporate Counsel Association. Ms. Santona is also a former member of the Board of Trustees of the Chicago Zoological Society and the Chicago Symphony Orchestra, and the Board of Directors of The Chicago Network, the Chicago Food Depository and the National Immigrant Justice Center. Skills & Qualifications: Ms. Santona’s legal background, including her experience serving as a general counsel and secretary of a large international corporation, brings critical perspective to the Board and enhances the Board’s global risk oversight capabilities. Ms. Santona’s diverse legal background contributes corporate governance, legal, regulatory and compliance expertise and further brings valuable perspective on long-term growth strategy planning. Under Ms. Santona’s leadership, McDonald’s legal department won numerous awards for its commitment to inclusivity and pro bono, and Ms. Santona’s continuing service and leadership at non-profit organizations deepens the Board’s expertise on social and governance priorities.

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Sarah E. Smith Director since 2023 Age: 65 Committees: • Finance Committee		Ms. Smith is a former member of the Management Committee of The Goldman Sachs Group, Inc., a global investment banking, securities and investment management firm. Ms. Smith joined Goldman Sachs in 1996 and was named Managing Director in 1998 and Partner in 2002. During her tenure, Ms. Smith served as the Controller and Chief Accounting Officer of the firm until 2017, and subsequently as the Chief Compliance Officer from 2017 to 2020. Ms. Smith then served as Senior Advisor to Goldman Sachs from 2020 until her retirement in 2021. Prior to joining Goldman Sachs, Ms. Smith worked in the National and Audit practices of KPMG in both London and New York and held several finance positions at Bristol-Myers Squibb. Ms. Smith is a member of the Board of Trustees of the Financial Accounting Foundation since September 2020. Ms. Smith attended City of London University (Dip. Acc), and is a Fellow of the Institute of Chartered Accountants in England and Wales. Ms. Smith serves as a Trustee of the Nuveen Churchill Private Capital Income Fund and as a board member for three private companies: Klarna Bank A.B., Via Transportation and 98point6. Skills & Qualifications: Ms. Smith’s background as a chief accounting officer and chief compliance officer provides the Board with an increased level of financial literacy and enhances the Board’s expertise in the oversight of risk management and compliance. In addition, Ms. Smith’s experience in the investment banking and asset management industries brings valuable insight to the Company’s business operations in professional and financial services.
Byron O. Spruell Director since 2020 Age: 59 Committees: • Audit Committee • Organization and Compensation Committee • Inclusion & Wellbeing Sub-Committee		Mr. Spruell is the President of League Operations at the National Basketball Association, a position he has held since August 2016. Prior to joining the National Basketball Association, Mr. Spruell spent 20 years at Deloitte LLP, most recently as its Vice Chairman, Central Region Marketplace Leader and Chicago Managing Principal. He serves on several non-profit boards, including the University of Notre Dame Board of Trustees, the Museum of Science and Industry, Metropolitan Family Services in Chicago and the Jackie Robinson Foundation. Skills & Qualifications: Mr. Spruell’s background in a professional services firm and as a current executive at the National Basketball Association provides the Board with valuable experience in operations management, agility, talent development, application of analytics and innovation, business continuity and colleague health and wellness. Mr. Spruell’s experiences at Deloitte LLP and as Chair of the Audit Committee of the University of Notre Dame’s Board of Trustees further elevates the Board’s financial and accounting expertise. Additionally, Mr. Spruell’s service on non-profit boards enhances the Board’s perspectives around community engagement and social impact.

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Audit Committee

The Company has a separately-designated standing Audit Committee established in accordance with Section 3(a)(58)(A) of the Exchange Act. The primary purposes of the Audit Committee are to assist the Board with the oversight of: (i) the integrity of Aon’s financial statements, financial reporting process and internal controls; (ii) Aon’s compliance with legal and regulatory requirements and compliance and ethics programs, policies and procedures; (iii) the engagement of Aon’s independent auditor and its qualifications, independence and performance; (iv) subject to the provisions of Irish law, the appointment and performance of Aon’s statutory auditor as required under Irish law; and (v) the performance of Aon’s internal audit function. The Audit Committee is authorized to retain outside counsel or other experts as it deems appropriate to carry out its duties and responsibilities.

The Board has also delegated to the Audit Committee the primary responsibility for the oversight of the Company’s risk management. The Audit Committee reviews and discusses with management Aon’s guidelines and policies with respect to risk assessment and enterprise risk management, including the major financial risk exposures facing the Company and the steps management has taken to monitor and control such exposures. The Audit Committee also has primary responsibility for oversight of cybersecurity risk and engages in regular discussion with management regarding cybersecurity risk mitigation and incident management. The Audit Committee also has general oversight responsibility for the Company’s legal, regulatory, and ethics policies and programs and annually reviews the adequacy of those policies and programs, including Aon’s Code of Business Conduct. In addition, the Audit Committee periodically reviews with management any material correspondence with, or other action by, regulators or governmental agencies.

The current members of the Audit Committee are Jeffrey C. Campbell, Jose Antonio Álvarez, Fulvio Conti, Adriana Karaboutis, Gloria Santona, Byron O. Spruell and Carolyn Y. Woo. In 2023, the Audit Committee met nine times. The Board has determined that each of the members of the Audit Committee is independent as defined by the rules of the New York Stock Exchange (“NYSE”) and under the Company’s categorical independence standards, as well as Rule 10A-3 under the Exchange Act. In addition, as required by the rules of the NYSE, the Board has determined that all of the Audit Committee members are financially literate, and that Mr. Álvarez, Mr. Campbell, and Mr. Conti are “audit committee financial experts” within the meaning of rules promulgated by the SEC.

Shareholder Recommendations

The Governance/Nominating Committee will consider shareholder recommendations for director nominees. Recommendations, together with the name and address of the shareholder making the recommendation, relevant biographical information regarding the proposed nominee and a description of any arrangement or understanding between the shareholder and the proposed nominee, should be sent to the Company Secretary. Shareholder recommendations for director candidates to stand for election at the 2025 annual general meeting must be submitted in writing to the Company Secretary, Aon plc, Metropolitan Building, James Joyce Street, Dublin 1, Ireland. Recommendations will be forwarded to the Chair of the Governance/Nominating Committee for review and consideration.

Hedging and Pledging Shares

The Board has adopted an insider trading policy which is available on the Company’s website and described in the Company’s code of ethics, which is also available on the website as disclosed in Part 1 of the Original Filing. The Company’s insider trading policy specifically prohibits all directors and employees from engaging in short sales, publicly traded options, puts and calls, forward sale contracts, and other swap, hedging and derivative transactions relating to our securities. The policy also specifically prohibits our executive officers and directors from holding our securities in margin accounts or pledging our securities as collateral for a loan.

Delinquent Section 16(a) Reports

Section 16(a) of the Exchange Act requires that each of our directors and executive officers, and any other person who owns more than ten percent (10%) of our Class A Ordinary Shares, file with the SEC initial reports of ownership and reports of changes in ownership of our Class A Ordinary Shares. To our knowledge, based solely on information furnished to us and written representations by such persons that no such other reports were required to be filed, Aon believes that all such SEC filing requirements were met in a timely manner during 2023 other than with respect to a Form 3 filed on behalf of Ms. Smith, which was timely filed but subsequently amended to correct the number of shares beneficially owned.

Corporate Governance Materials Available on Website

We have adopted a code of ethics that applies to the Company’s directors, officers, and employees, including the Chief Executive Officer, Chief Financial Officer, Controller, and Chief Accounting Officer and other persons performing similar functions. The text of our code of ethics, which we call our Code of Business Conduct, is available on our website as disclosed in Part 1 of the Original Filing. We will provide a copy of the code of ethics without charge upon request to the Company Secretary, Metropolitan Building, James Joyce Street, Dublin 1, Ireland. We will disclose on our website any amendment to or waiver from our code of ethics on behalf of any of our executive officers or directors.

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Compensation Discussion and Analysis

This Compensation Discussion and Analysis (“CD&A”) describes our executive compensation program for our Named Executive Officers (each an “NEO” and collectively the “NEOs”), who are listed below, for 2023. We recommend that you read this section in conjunction with the executive compensation tables and corresponding footnotes that follow, as it provides context for the amounts shown in the tables and the footnote disclosures.

Name		Role
Gregory C. Case		Chief Executive Officer
Christa Davies (1)		Executive Vice President and Chief Financial Officer
Eric Andersen		President
Lisa Stevens		Executive Vice President and Chief People Officer
Darren Zeidel		Executive Vice President, General Counsel, and Company Secretary

(1) On April 1, 2024, Ms. Davies notified the Company of her intention to retire from the position of Chief Financial Officer. Ms. Davies is expected to serve as Chief Financial Officer into the third quarter of 2024 and is thereafter expected to serve as a senior advisor for a transition period into 2025.

Executive Summary

Who We Are

Aon exists to shape decisions for the better — to protect and enrich the lives of people around the world. Our colleagues provide our clients in over 120 countries and sovereignties with advice and solutions that give them the clarity and confidence to make better decisions to protect and grow their business.

2023 Business Highlights

In assessing our performance, we focus on our performance against four non-Generally Accepted Accounting Principles (“GAAP”) metrics that we communicate to shareholders: organic revenue growth, adjusted operating margin, adjusted diluted earnings per share, and free cash flow. Management believes that these measures are important to make meaningful period-to-period comparisons and that this supplemental information is helpful to investors. Management also uses these measures to assess operating performance and performance for compensation. These non-GAAP metrics should be viewed in addition to, not instead of, our consolidated financial statements and notes thereto. A reconciliation of these non-GAAP metrics to the most directly comparable GAAP metrics is set forth in Appendix A to this Amendment.

In 2023, we continued to deliver across these four metrics:

	•		Total revenue growth was 7% compared to 2022, reflecting organic revenue growth of 7%, driven by the ongoing strength of our Aon United strategy, and a 2% favorable impact from fiduciary investment income, partially offset by a 2% unfavorable impact from acquisitions, divestitures and other.

	•		Operating margin was 28.3% and adjusted operating margin was 31.6%, driven by revenue growth outpacing expense growth and long-term investments.

	•		Diluted earnings per share was $12.51 and adjusted diluted earnings per share was $14.14, reflecting strong operational performance and effective capital management, highlighted by $2.7 billion of share repurchases during 2023, partially offset by an unfavorable impact from higher non-cash pension expense and other non-operating expenses.

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	•		Cash flows provided by operating activities was $3.4 billion in 2023, an increase of $216 million, or 7%, from $3.2 billion in 2022, reflecting strong operating income growth and overall working capital optimization, partially offset by higher cash tax payments and a negative impact to working capital due to temporary invoicing delays associated with the implementation of a new system. Free cash flow was $3.2 billion in 2023, an increase of $160 million, or 5%, from $3.0 billion in 2022, reflecting an increase in cash flows from operations, partially offset by a $56 million increase in capital expenditures.

Performing at the levels described above allows us to continue to execute on our goals of strategically investing in long-term growth, improving return on invested capital over the long term, and effectively allocating capital.

During 2023, we returned nearly $3.2 billion of capital to our shareholders through share repurchases and dividends, which highlights our strong cash flow generation and effective allocation of capital. Our consistent focus on the four key metrics and our capital allocation strategy has helped drive meaningful total shareholder returns throughout the tenure of our senior management team. Specifically, during Mr. Case’s leadership, which began in April 2005, our average annual total shareholder return has been 16%, compared to the return of the benchmark Standard & Poor’s (the “S&P”) 500 of 8% and 12% for our industry peer averages (Arthur J. Gallagher & Co., Brown & Brown, Inc., Marsh & McLennan Companies, Inc., and Willis Towers Watson Public Limited Company). We believe we are well positioned to create long-term value by driving growth and operating performance, resulting in strong free cash flow generation.

We compensate our senior executives through incentive programs that measure both long-term and short-term performance. Our regular long-term incentive plan (described in this CD&A under “Long-Term Leadership Performance Program Under Our Shareholder-Approved Plan”) is based on cumulative adjusted diluted earnings per share, a measure driven by operational performance and capital management, across overlapping three-year performance periods. Our short-term incentive plan (described in this CD&A under “Annual Incentive Awards Under Our Shareholder-Approved Plan”) is primarily based on adjusted operating income, a measure driven by operating margin and organic revenue growth, as well as a people and culture component, which assesses the Company’s progress against inclusion and diversity objectives.

We achieved strong results across these metrics, which were the key performance measures under our 2021-2023 long-term and 2023 annual incentive compensation plans. Set forth below are the results across these metrics as well as the results against their GAAP comparative metrics:

	•		$30.20 cumulative diluted earnings per share for 2021-2023; $38.75 Leadership Performance Program (“LPP”) cumulative adjusted diluted earnings per share for 2021-2023, as compared to target LPP cumulative adjusted diluted earnings per share of $32.47; and

	•		$3,785M operating income; $4,223M adjusted operating income, an increase of 10% year-over-year.

In addition, the Company has progressed our inclusion and diversity initiatives and has advanced representations in leadership roles for women and racially diverse leaders globally and in the United States, advanced our recruitment of candidates from diverse backgrounds, and has significantly exceeded our learning goals for all colleagues on inclusion topics.

In addition, in December 2023, we entered into a definitive agreement to acquire NFP, a leading middle market property and casualty broker, benefits consultant, wealth manager, and retirement plan advisor, for an aggregate purchase price of (i) approximately $7 billion in cash and (ii) approximately 20,000,000 class A ordinary shares of the Company (“Class A Ordinary Shares”).

Features of Our Executive Compensation Program

The following table provides an overview of our compensation program elements for our NEOs. The guiding philosophy underlying our executive compensation program is to provide a fair, flexible, and market-based total compensation package that is meaningfully tied to the Company’s short- and long-term performance and aligned with the interests of our shareholders.

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		Element		**Desc

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Equity Compensation Plan Information

The following table summarizes the number of Class A Ordinary Shares that may be issued under our equity compensation plans as of December 31, 2023.

Plan Category		Number of securities to be issued upon exercise of outstanding options, warrants and rights (a)															Weighted average exercise price of outstanding options, warrants and rights (b)															Number of securities remaining available for future issuance under equity compensation plans (excluding securities reflected in column (a)) (c)
Equity compensation plans approved by security holders									5,424,182	(1)(2)														299.17	(3)														6,787,487	(4)
Equity compensation plans not approved by security holders(5)									273,069															—	(6)														—	(7)
Total									5,697,251															299.17															6,787,487

(1)	This amount includes the following:

	–	2,665,329 shares that may be issued in connection with share awards under the Shareholder-Approved Plan;

	–	543,995 shares that may be issued in connection with outstanding options under the Shareholder-Approved Plan.

	–	8,351 shares that may be used in connection with share awards under the 2001 Aon Stock Incentive Plan;

	–	13,966 shares that may be issued in connection with deferred share awards under the 2001 Aon Stock Incentive Plan;

	–	81,973 shares that may be issued in connection with the US employee share purchase plan;

	–	132,586 shares that may be issued in connection with the UK ShareSave share plan;

	–	23,073 shares that may be issued to satisfy obligations under the Aon Deferred Compensation Plan in connection with the 2001 Aon Stock Incentive Plan; and

	–	1,954,909 shares that may be issued in connection with the settlement of PSUs under the Shareholder-Approved Plan. For awards where the performance period has been completed, the actual number of shares to be issued is shown. For awards tracking significantly below threshold, the threshold number of shares which may be issued is shown. For all other performance share awards, the maximum number of shares which may be issued is shown.

(2)	On November 1, 2002, the Aon Deferred Compensation Plan was amended to discontinue the distribution of shares with respect to deferrals after November 1, 2002, from that plan. As of December 31, 2023, based on a share price of $291.02, the maximum number of shares that could be issued under the Aon Deferred Compensation Plan was 23,073.

(3)	Indicates weighted average exercise price of 543,995 outstanding options under the Shareholder-Approved Plan.

(4)

The total number of Class A Ordinary Shares authorized for issuance in connection with awards under the Shareholder-Approved Plan is 42,800,000. As of December 31, 2023, 4,587,147 shares remained available for future issuance under this plan. The amount shown in column (c) also includes 2,200,340 shares available for future issuance under the Aon plc Global Share Purchase Plan, including 81,973 shares subject to purchase as of December 31, 2023. Permissible awards under the Shareholder-Approved Plan include share options, share appreciation rights, restricted shares, restricted share units and other share-based awards, including awards where the vesting, granting or settlement of which is contingent upon the achievement of specified performance goals, called “performance awards.”

(5)	Below are the material features of our equity compensation plans that have not been approved by shareholders:

Aon Supplemental Savings Plan

The Supplemental Savings Plan (SSP) was adopted by the board of directors of Aon Corporation in 1998. It is a nonqualified supplemental retirement plan that provides benefits to participants in the Aon Savings Plan whose employer matching contributions are limited because of IRS-imposed restrictions. The plan originally allowed contributions to be credited to a Class A Ordinary Shares account. All amounts credited to a Class A Ordinary Shares account were then credited with dividends and other investment returns as under the Aon Savings Plan fund and are settled in Class A Ordinary Shares. Prior to April 1, 2017, before the beginning of each plan year, an election could be made by any participant to transfer some or all of a participant’s existing money market account under the SSP to Class A Ordinary Shares account. Beginning April 1, 2017, no new contributions are permitted to be invested in a Class A Ordinary Shares account and no amounts may be transferred out of such account to another investment option.

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Under the SSP, eligible employees receive a supplemental allocation based on years of service (between 3 and 6 percent of eligible compensation) and are credited with an additional matching allocation they would have received under the Aon Savings Plan match provision had compensation up to $500,000 been considered. Participants must also contribute the limit prescribed by the IRS ($22,500 for 2023) and be active on the last day of the year to receive the allocation. As of December 31, 2023, the number of shares that could be issued under the plan was 189,735.

Aon Supplemental Employee Stock Ownership Plan

The Aon Supplemental Employee Stock Ownership Plan was a plan established in 1989 as a nonqualified supplemental retirement plan that provided benefits to participants in the Aon Employee Stock Ownership Plan whose employer contributions were limited because of IRS-imposed restrictions. As of 1998, no additional amounts have been credited to participant accounts. Account balances are maintained for participants, and credited with dividends, until distribution is required under the plan. Distributions are made solely in Class A Ordinary Shares. No specific authorization of Class A Ordinary Shares for the plan has been made. As of December 31, 2023, the number of shares that could be issued under the plan was 83,334.

(6)	The weighted-average exercise price of such shares is uncertain and is not included in this column.

(7)	None of these equity compensation plans contain a limit on the number of shares that may be issued under such plans; however, these plans are subject to the limitations set forth in the descriptions of these plans contained in Note 5 above.

Security Ownership of Certain Beneficial Owners and Management

Security Ownership of Directors and Executive Officers

The following table sets forth the number of Class A Ordinary Shares beneficially owned as of April 12, 2024 by each of Aon’s directors, nominees and NEOs and by Aon’s directors and executive officers as a group. As used in this Amendment, “beneficially owned” means a person has, or may have within 60 days, the sole or shared power to vote or direct the voting of a security and/or the sole or shared investment power with respect to a security (i.e., the power to dispose or direct the disposition of a security). No shares held by Aon’s directors or executive officers are pledged as security. The address of each person named in the table below is c/o Aon plc, Metropolitan Building, James Joyce Street, Dublin 1, Ireland.

Name		Aggregate Number of Class A Ordinary Shares Beneficially Owned1				Percent of Class2
Directors
Lester B. Knight3			363,461				*
Gregory C. Case4			1,542,602				*
Jose Antonio Álvarez			141				*
Jin-Yong Cai			6,756				*
Jeffrey C. Campbell			10,970				*
Fulvio Conti			30,467				*
Cheryl A. Francis			27,643				*
Adriana Karaboutis			955				*
Richard C. Notebaert			33.497				*
Gloria Santona			38,547				*
Sarah E. Smith			476				*
Byron O. Spruell			4,001				*
Carolyn Y. Woo			27,278				*
Other NEOs
Christa Davies			161,706				*
Eric Andersen			161,118				*
Lisa Stevens			9,723				*
Darren Zeidel5			31,051				*
All directors and executive officers as a group (21 persons) 5			2,504,150				1.3	%

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(1)	The directors, nominees and NEOs, and all directors and executive officers of Aon combined, have sole voting power and sole investment power over the Class A Ordinary Shares listed, except as indicated in notes (3), (4), and (5).

(2)	As of April 12, 2024, we had 198,506,718 Class A Ordinary Shares outstanding.

(3)	Includes 134,000 Class A Ordinary Shares that are beneficially owned by family partnership, 124,604 Class A Ordinary Shares owned by Mr. Knight’s spouse, 83,911 Class A Ordinary Shares owned in trusts, and 19,997 Class A Ordinary Shares owned by a family foundation of which Mr. Knight and his spouse are trustees.

(4)	Includes 622,985 Class A Ordinary Shares that are beneficially owned in trust and 547,075 Class A Ordinary Shares held by trusts for which an immediate family member serves as trustee.

(5)	Includes Class A Ordinary Shares that may be acquired by vesting of restricted stock units (“RSUs”) within 60 days after April 12, 2024.

*	An asterisk indicates that the percentage of Class A Ordinary Shares beneficially owned does not exceed 1% of our outstanding Class A Ordinary Shares.

Principal Holders of Voting Securities

As of April 12, 2024, the beneficial owners of 5% or more of Aon’s Class A Ordinary Shares entitled to vote at the Annual Meeting and known to the Company were:

Name and Address of Beneficial Owner		Number of Class A Ordinary Shares				Percent of Class(1)
The Vanguard Group 100 Vanguard Blvd. Malvern, PA 19355			17,596,572	2			8.86	%
BlackRock, Inc. 50 Hudson Yards New York, NY 10001			13,428,205	3			6.76	%
Massachusetts Financial Services Company 111 Huntington Avenue Boston, MA 02199			12,472,491	4			6.72	%

(1)	As of April 12, 2024, we had 198,506,718 Class A Ordinary Shares outstanding.

(2)

Based upon information contained in a Schedule 13G/A filed with the SEC on February 13, 2024, pursuant to Rule 13d-1(b) of the Exchange Act. The Vanguard Group is an investment advisor and has (a) sole voting power as to no Class A Ordinary Shares; (b) shared voting power as to 249,859 Class A Ordinary Shares; (c) sole dispositive power as to 16,751,944 Class A Ordinary Shares; and (d) shared dispositive power as to 844,628 Class A Ordinary Shares.

(3)

Based upon information contained in a Schedule 13G/A filed with the SEC on February 1, 2024, pursuant to Rule 13d-1(b) of the Exchange Act. BlackRock, Inc. is a parent holding company and has: (a) sole voting power as to 12,078,011 Class A Ordinary Shares; (b) shared voting power as to no Class A Ordinary Shares; (c) sole dispositive power as to 13,428,205 Class A Ordinary Shares; and (d) shared dispositive power as to no Class A Ordinary Shares.

(4)

Based upon information contained in a Schedule 13G/A filed with the SEC on February 9, 2024, pursuant to Rule 13d-1(b) of the Exchange Act. Massachusetts Financial Services Company is an investment adviser and has: (a) sole voting power as to 11,557,331 Class A Ordinary Shares; (b) shared voting power as to no Class A Ordinary Shares; (c) sole dispositive power as to 12,472,491 Class A Ordinary Shares; and (d) shared dispositive power as to no Class A Ordinary Shares.

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Certain Relationships and Related Transactions

There have been no related person transactions or pending related person transactions since January 1, 2023 that require disclosure pursuant to Item 404 of Regulation S-K. Aon has adopted a written Related Person Transaction Policy governing the review and approval of related person transactions. The terms of these procedures provide that the Governance/Nominating Committee will review transactions in which: (i) Aon is a party or participant; and (ii) any director, director nominee, executive officer, or holder of five percent (5%) or more of Aon’s voting securities, an immediate family member of any such person or an entity controlled by any such person or immediate family member, has a direct or indirect material interest. To facilitate the review and approval of related person transactions, Aon’s directors and executive officers complete an annual director and officer questionnaire and disclose all potential related person transactions involving themselves and their immediate family members. Throughout the year, directors and executive officers are required to notify Aon’s General Counsel of any potential related person transactions of which they become aware. Aon’s General Counsel reports these transactions, as well as any other related person transactions of which he is aware, to the Governance/Nominating Committee. The Governance/Nominating Committee considers all relevant facts of any related person transactions to determine whether to approve or ratify the transaction.

Director Independence

Aon’s Corporate Governance Guidelines require that a majority of directors meet the independence requirements of NYSE. The Corporate Governance Guidelines further provide that each of the Audit Committee, Governance/Nominating Committee and Compensation Committee be composed entirely of independent directors.

The Board has affirmatively determined that each nominee for director other than Mr. Case is independent. Mr. Case is considered a management director because of his position as our Chief Executive Officer. In addition, the Board has affirmatively determined that J. Michael Losh, who retired as a director effective as of June 16, 2023, was independent during the time he served on the Board and that Dr. Woo, who will be retiring from the Board effective as of the Annual Meeting, is independent.

In determining that each of the non-management directors is independent, the Board also considered the following relationships that it deemed were immaterial to such director’s independence:

	•		With respect to Mr. Knight, Mr. Campbell, Ms. Karaboutis, and Mr. Spruell, the Board considered that, in the ordinary course of business, Aon has sold services to, or received services from, a company or other entity at which the director is (or during 2023 was) an employee and the amount that we received from or paid to the entity in any of the previous three fiscal years was below the greater of $1 million or two percent (2%) of that entity’s annual revenue; and

	•		With respect to Mr. Knight, Mr. Álvarez, Ms. Francis, Mr. Notebaert, Ms. Santona, and Mr. Spruell, the Board considered that Aon or certain of its affiliates made charitable contributions in 2023 to organizations in which the director or the director’s spouse was an officer, director, or trustee. In each case, the amount that we contributed was below the greater of $1 million or two percent (2%) of that organization’s consolidated gross revenue.

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The following is a summary of the fees billed by Ernst & Young LLP for professional services rendered for the years ended December 31, 2023 and December 31, 2022:

Type of Fees		2023 ($ in millions)				2022 ($ in millions)
Audit			17.3				15.4
Audit-Related			1.5				1.4
Tax			.5				.3
All Other Fees			—				—
Total Fees			19.3				17.1

Audit Fees

Audit fees included services associated with the annual audit, including fees related to Section 404 of the Sarbanes Oxley Act of 2002, as amended, the reviews of Aon’s documents filed with the SEC and substantially all statutory audits required domestically and internationally.

Audit-Related Fees

Audit-related fees include services such as employee benefit plan audits, other attestation services, due diligence in connection with acquisitions and accounting consultations not included in audit fees.

Tax Fees

Tax fees consist of fees for tax services, including tax compliance, tax advice and tax planning.

All Other Fees

The fees in this category pertain to permissible services not related to financial reporting.

Audit Committee’s Pre-Approval Policies and Procedures

The Audit Committee pre-approves all audit and permissible non-audit services provided by the independent registered public accounting firm. These services may include audit services, audit-related services, tax services and other services. Each pre-approval provides details regarding the particular service or category of service to be provided. The Audit Committee requires that the independent registered public accounting firm and management report on the actual fees charged by the independent registered public accounting firm for each category of service at Audit Committee meetings held during the year.

The Audit Committee may pre-approve engagements either on a case-by-case basis or on a category basis. The Audit Committee grants pre-approvals for certain categories of services at the start of each year which are applicable for the year. In considering these pre-approvals, the Audit Committee reviews a description of the scope of services falling within each category and approves budgetary limits for each category. The Audit Committee acknowledges that circumstances may arise throughout the year that require the engagement of the independent registered public accounting firm to provide additional services not contemplated in the Audit Committee’s initial pre-approval process. In those circumstances, the Audit Committee requires that specific pre-approval be obtained for any audit or permitted non-audit service that is not included in an approved category, or for which total fees are expected to exceed the relevant budgetary limits. The Audit Committee also requires specific pre-approval be obtained for any services in the other services category.

The Audit Committee has delegated pre-approval authority to the Chair of the Audit Committee for those instances when pre-approval is needed prior to a scheduled Audit Committee meeting. Such pre-approvals are reported to the Audit Committee at the next scheduled Audit Committee meeting.

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PART IV

Exhibit Index

31.1+		Rule 13a-14(a) Certification of Chief Executive Officer of Aon in accordance with Section 302 of the Sarbanes-Oxley Act of 2002.
31.2+		Rule 13a-14(a) Certification of Chief Financial Officer of Aon in accordance with Section 302 of the Sarbanes-Oxley Act of 2002.
(104)*		Cover Page Interactive Data File - the cover page interactive data file does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document (included in Exhibit 101).
*		Submitted electronically with this Amendment.
+		Filed herewith.

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this Amendment to be signed on its behalf by the undersigned, thereunto duly authorized.

Aon plc
By:		/s/ Gregory C. Case
		Gregory C. Case, Chief Executive Officer

Date:  April 17, 2024

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Appendix A

Reconciliation of Non-GAAP Measures

Aon plc

Reconciliation of Non-GAAP Measures—Organic Revenue Growth and Free Cash Flow (Unaudited)

Organic Revenue Growth (Unaudited)

		Years Ended
(millions)		December 31, 2023				December 31, 2022				% Change				Less: Currency Impact (1)				Less: Fiduciary Investment Income (2)				Less: Acquisitions, Divestitures & Other				Organic Revenue Growth (3)
Revenue
Commercial Risk Solutions		$	7,043			$	6,715				5	%			-	%			2	%			(2	)%			5	%
Reinsurance Solutions			2,481				2,190				13				(1	)			4				-				10
Health Solutions			2,433				2,224				9				-				-				(1	)			10
Wealth Solutions			1,431				1,367				5				-				-				1				4
Elimination			(12	)			(17	)			N/A				N/A				N/A				N/A				N/A
Total revenue		$	13,376			$	12,479				7	%			-	%			2	%			(2	)%			7	%

(1)	Currency impact represents the effect on prior year period results if they were translated at current period foreign exchange rates.

(2)	Fiduciary investment income for the years ended December 31, 2023, 2022, and 2021 was $274 million, $76 million, and $8 million, respectively.

(3)

Organic revenue growth includes the impact of certain intercompany activity and excludes the impact of changes in foreign exchange rates, fiduciary investment income, acquisitions, divestitures (including held for sale disposal groups, which had a 1% favorable impact on total organic revenue growth for the year-ended December 31, 2023), transfers between revenue lines, and gains or losses on derivatives accounted for as hedges.

Free Cash Flow (Unaudited)

		Years Ended December 31
(millions)		2023				2022				% Change
Cash provided by operating activities		$	3,435			$	3,219				7	%
Capital expenditures			(252	)			(196	)			29	%
Free cash flows(1)		$	3,183			$	3,023				5	%

(1)	Free cash flows is defined as cash flow provided by operations minus capital expenditures and as a non-GAAP measure of our core operating performance and cash generating capabilities of our business operations. This non-GAAP measure does not imply or represent a precise calculation of residual cash flow available for discretionary expenditures.

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Aon plc

Reconciliation of Non-GAAP Measures—Operating Income and Diluted Earnings Per Share (Unaudited)(1)

		Years Ended December 31
(millions except percentages)		2023				2022				% Change
Revenue		$	13,376			$	12,479				7%
Operating income		$	3,785			$	3,669				3%
Amortization and impairment of intangible assets			89				113				(21)%
Accelerating Aon United Program expenses (2)			135				-				100%
Legal settlements (3)			197				58				240%
Transaction costs (4)			17				-				100%
Operating income—as adjusted		$	4,223			$	3,840				10%
Operating margin—as reported			28.3	%			29.4	%
Operating margin—as adjusted			31.6	%			30.8	%
		Years Ended December 31
(millions except percentages)		2023				2022				% Change
Operating income—as adjusted		$	4,223			$	3,840				10%
Interest income			31				18				72%
Interest expense			(484	)			(406	)			19%
Total Other income (expense)—as adjusted (5)			(136	)			45				(402)%
Income before income taxes—as adjusted			3,634				3,497				4%
Income tax expense (6)			671				585				15%
Net income—as adjusted			2,963				2,912				2%
Less: Net income attributable to noncontrolling interests			64				57				12%
Net income attributable to Aon shareholders—as adjusted			2,899				2,855				2%
Diluted net income per share attributable to Aon shareholders—as adjusted		$	14.14			$	13.39				6%
Net income attributable to Aon shareholders—as reported		$	2,564			$	2,589				(1)%
Basic net income per share attributable to Aon shareholders		$	12.60			$	12.23				3%
Diluted net income per share attributable to Aon shareholders – as reported		$	12.51			$	12.14				3%
Weighted average ordinary shares outstanding - basic			203.5				211.7				(4)%
Weighted average ordinary shares outstanding - diluted			205.0				213.2				(4)%
Effective tax rates (6)
U.S. GAAP			17.1	%			16.2	%
Non-GAAP			18.5	%			16.7	%

(1)	Certain noteworthy items impacting operating income in 2023 and 2022 are described in this schedule. The items shown with the caption “as adjusted” are non-GAAP measures.

(2)	Total charges related to the Accelerating Aon United Program are expected to include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation costs.

(3)

In the fourth quarter of 2023, Aon recognized actual and anticipated legal settlement expenses in connection with transactions for which capital was arranged by a third party, Vesttoo Ltd. primarily in the form of letters of credit from third party banks that are alleged to have been fraudulent. Certain actual or anticipated legal settlements expenses totaling $197 million have been recognized in the current period, where certain potentially

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	meaningful amounts may be recoverable in future periods. Additionally, a $58 million charge was recognized in the second quarter of 2022 with certain other legal settlements reached in matters unrelated to Vesttoo.

(4)	In the fourth quarter of 2023, we entered into a definitive agreement to acquire NFP. As part of the definitive agreement, certain transaction costs were incurred including advisory, legal, accounting, and other professional or consulting fees required to complete the acquisition.

(5)

To further our pension de-risking strategy, we settled certain pension obligations in the Netherlands through the purchase of annuities, where certain pension assets were liquidated to purchase the annuities. A non-cash settlement charge totaling $27 million was recognized in the second quarter of 2023, which is excluded from the 2023 Total Other income (expense) - as adjusted. We also purchased an annuity for portions of our U.S. pension plans that will settle certain obligations. A non-cash settlement charge totaling $170 million was recognized in the fourth quarter of 2022, which is excluded from the 2022 Total Other income (expense) - as adjusted.

(6)

Adjusted items are generally taxed at the estimated annual effective tax rate, except for the applicable tax impact associated with the anticipated sale of certain assets and liabilities classified as held for sale, certain pension and legal settlements, AAU Program expenses, and certain transaction costs and other charges related to the definitive agreement to acquire NFP, which are adjusted at the related jurisdictional rate.

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