Aon 10-K 2024-12-31

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

Commission file number: 1-7933

Aon plc

(Exact name of registrant as specified in its charter)

+353 1 266 6000

(Registrant’s Telephone Number, including area code)

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

S****ecurities 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 Exchange 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.

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 Exchange Act). Yes ☐ No ☒

As of June 28, 2024, the aggregate market value of the registrant’s Class A Ordinary Shares held by non-affiliates of the registrant was $63,751,112,781 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 of February 14, 2025: 216,001,106.

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 Part III, Items 10, 11, 12, 13, and 14.

Information Concerning Forward-Looking Statements

This report 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,” “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 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; 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 Securities and Exchange Commission, 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. or related to 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 may provide in the future);

• 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;

• 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 conflicts in the Middle East;

• the effects of natural or human-caused 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;

• 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, 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 realize the expected benefits of the acquisition of NFP (including anticipated revenue and growth synergies) in the expected timeframe, or at all; and

• significant integration costs in connection with the acquisition of NFP or unknown or inestimable liabilities.

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 this report.

Table of Contents

The below definitions apply throughout this report unless the context requires otherwise:

PART I

OVERVIEW

Aon plc (which may be referred to as “Aon,” the “Company,” “we,” “us,” or “our”) is a leading global professional services firm providing a broad range of Risk Capital and Human Capital solutions. Through our experience, global reach, and comprehensive analytics, we help clients meet rapidly changing, increasingly complex, and interconnected challenges related to risk and people. We are committed to accelerating innovation to address unmet and evolving client needs so that our clients are better informed, better advised, and able to make better decisions to protect and grow their business. Management remains focused on strengthening Aon and uniting the firm through its Aon United strategy, with capabilities delivered through Risk Capital and Human Capital and enabled by data and analytics to deliver additional insight, connectivity, and efficiency.

Our clients are in over 120 countries and include all market segments and almost every industry. This diversification of our customer base helps provide us stability in different economic scenarios that could affect specific industries, customer segments, or geographies.

We have continued to focus our portfolio on higher-margin, capital-light professional services businesses that have high recurring revenue streams and strong cash flow generation. We endeavor to make capital allocation decisions in order to maximize value for Aon and its shareholders.

BUSINESS SEGMENTS

The Company formerly operated as one reportable segment under Aon United, which included all of Aon’s operations. Beginning in the fourth quarter of 2024, the CODM assesses the performance of the Company and allocates resources based on two segments: Risk Capital and Human Capital. This segmentation will align with how the Company addresses client needs, accelerating its Aon United strategy and maximizing value for Aon and its shareholders. Differences between the reportable segments’ results and Aon’s consolidated results include certain inter-segment revenues, as well as unallocated expenses. Prior period comparative segment information has been recast to conform with current year presentation, which reflects the way our CODM internally receives information and manages and monitors our reportable operating segment performance. The accounting policies of the reportable segments are the same as those described in Note 2 “Summary of Significant Accounting Principles and Practices.”

In 2024, our consolidated Total revenue was $15,698 million. This includes $10,517 million in Risk Capital and $5,209 million in Human Capital before certain intercompany eliminations.

Principal Products and Services

Risk Capital

Commercial Risk Solutions uses Risk Capital’s extensive data and analytics capabilities to provide brokerage and consulting services that help organizations develop, improve, and implement their risk management strategies. Commercial Risk Solutions includes insurance and specialty brokerage, global risk consulting, captives management, and Affinity programs. In insurance brokerage, our dedicated teams of risk professionals utilize comprehensive analytics to design strategically resilient insurance programs and provide our clients access to Aon’s proprietary facilities, such as Aon Client Treaty and all other forms of capital, regardless of insurance carrier, placement structure or geography. Throughout the year, we review analytics specific to clients’ losses and exposures, and we evaluate new risk transfer techniques to be considered in the current market conditions. Commercial Risk Solutions is organized around industry and product, including but not limited to property, casualty, financial and professional lines, construction, transportation, energy, cyber, surety, trade credit, crisis management, transaction liability, and climate. Aon’s Global Risk Consulting and Captive Management teams use quantitative analytics to advise on the trade-offs between risk retention and risk transfer as well as to provide claims consulting and advocacy to ensure optimal financial recovery. Aon’s Affinity business collaborates with sponsored groups and other distribution channels to develop, market, and administer customized insurance programs. Commercial Risk’s global reach enables seamless client service in all geographies including Aon’s Global Broking Centers in London, Bermuda and Singapore.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, Strategy and Technology Group and capital markets. Treaty reinsurance addresses underwriting and capital objectives on a portfolio level, allowing our clients to more effectively manage the combination of premium growth, return on capital, and rating agency interests on an integrated basis. This includes the development of more competitive, innovative, and efficient risk transfer options. Facultative reinsurance empowers clients to better understand, manage, and transfer risk through innovative facultative solutions and provides the most efficient access to the global facultative reinsurance markets. Strategy and Technology Group combines strategic advice with

data-driven consulting, analytics, and modeling tools, including Tyche, ReMetrica, and PathWise, to help clients deploy capital efficiently and effectively. We develop highly customized solutions, enabled by innovative technology, that help clients drive growth and operational efficiency, improve balance sheet strength and resiliency, and comply with regulatory and operational requirements, including through the execution of reinsurance transactions. Capital markets is a global investment bank with expertise in insurance-linked securities, capital raising, strategic advice, restructuring, and mergers and acquisitions. We partner with insurers, reinsurers, investment firms, and corporations in executing innovative risk management products, capital market solutions and corporate finance advisory services.

Human Capital

Health Solutions includes consulting and brokerage, consumer benefits, and talent advisory services. Consulting and brokerage develops and implements innovative, customized health and benefits strategies for our clients to manage risk, drive engagement, and strengthen their workforce through improved health and wellbeing. We partner with insurers and other strategic partners to develop and implement new and innovative solutions and leverage world-class analytics and technology to help clients make informed decisions and manage healthcare outcomes. Consulting and brokerage also advises multinational companies on global benefits programs, including program design and management, financing optimization, and enhanced employee experience, as well as assists in navigating global regulatory and compliance requirements in over 120 countries. Consumer benefits solutions designs and delivers innovative voluntary consumer benefits programs that improve an employer’s total rewards strategy and positively impacts their employees’ financial and overall wellbeing. We leverage our proprietary digital platform to provide efficient enrollment strategies through an effective combination of data, analytics, and tailored products. Our talent team delivers data, analytics, and advice to business leaders so they can make better workforce decisions and align their business and people strategies. We support clients across the full employee lifecycle, including talent assessment and selection, compensation benchmarking, total rewards strategy optimization, Corporate Governance, ESG consulting, and strategic employee communications.

Wealth Solutions includes retirement consulting, pension administration, and investments consulting. Retirement consulting provides clients strategic design advice, actuarial services, risk management solutions including pension risk transfer, and integrated pension administration. We also help organizations manage their balance sheet volatility. Our investments advisory team provides corporations, public pensions, endowments and foundations with advice on developing and maintaining investment programs across a broad range of plan types, including defined benefit plans, defined contribution plans and Master Trusts. Our delegated investment solutions provide ongoing management of investment programs in both partial or full discretionary models. We partner with clients leveraging our expertise and scale to help them effectively manage their investment portfolio.

Revenue and Compensation

Our business generates revenues primarily through commissions, compensation from insurance and reinsurance companies for services we provide to them, and fees from customers. Commissions and fees for brokerage services vary depending upon several factors, which may include the amount of premium, the type of insurance or reinsurance coverage provided, the particular services provided to a client, insurer, or reinsurer, and the capacity in which we act. Compensation from insurance and reinsurance companies includes: (1) fees for consulting and analytics services, and (2) fees and commissions for administrative and other services provided to or on behalf of insurers and reinsurers. Fees from clients for advice and consulting services are dependent on the extent and value of the services we provide. Payment terms are consistent with current industry practices.

Funds Held on Behalf of Clients

We typically hold funds on behalf of clients, including premiums received from clients and claims due to clients that are in transit to and from insurers. Certain funds held on behalf of clients are invested in interest-bearing premium trust accounts and can fluctuate significantly depending on when we collect and remit cash. The principal is segregated and not available for general operating purposes, although we may earn interest on these accounts.

Competition

Our business operates in a highly competitive and fragmented environment. We compete with numerous other global insurance brokers and consulting companies, including, among others, Marsh & McLennan Companies, Inc., Willis Towers Watson Public Limited Company, Arthur J Gallagher & Company, and Lockton Companies, Inc., as well as numerous other global, regional, and local firms in almost every area of our business. We also compete with insurance and reinsurance companies that directly market and service their insurance products without the assistance of brokers or agents. Additionally, we compete with other businesses that do not fall into the categories above, including large financial institutions and independent consulting firms and consulting organizations affiliated with accounting, information systems, technology, human resources, and financial services firms.

Seasonality

Due to buying patterns and delivery of certain products and services in the markets we serve, revenues recognized tend to be higher in the first and fourth quarters of each fiscal year.

Licensing and Regulation

Our business activities are subject to licensing requirements and extensive regulation under the laws of countries in which we operate, including U.S. federal and state laws. See the “Risk Factors” section in Part I, Item 1A of this report for information regarding how actions by regulatory authorities or changes in legislation and regulation in the jurisdictions in which we operate may have an adverse effect on our business.

Regulatory authorities in the U.S. and most other countries in which our operating subsidiaries conduct business may require individuals, entities, and related service providers to obtain a license from a government agency, including (but not limited to) licenses to operate as insurance producers, brokers, agents, consultants, reinsurance brokers, or managing general agents.

Certain jurisdictions issue licenses only to resident entities or individuals. In such jurisdictions, if the Company has no licensed subsidiary, we may maintain arrangements with residents or business entities licensed to act in such jurisdiction. Such arrangements are subject to an internal review and approval process.

Our subsidiaries must comply with laws and regulations of the jurisdictions in which they do business. These laws and regulations are enforced by the FCA in the U.K., by federal and state agencies in the U.S., and by various regulatory agencies and other supervisory authorities in other countries through the granting and revoking of licenses to do business, the licensing of agents, the monitoring of trade practices, policy form approval, limits on commission rates, and mandatory remuneration disclosure requirements.

Insurance authorities in the U.K., U.S., and certain other jurisdictions in which our subsidiaries operate have enacted laws and regulations governing the investment of funds, such as premiums and claims proceeds, held in a fiduciary capacity for others. These laws and regulations generally require the segregation of these fiduciary funds and limit the types of investments that may be made with them.

Investment, securities, and futures licensing authorities also govern certain business activities. For example, in the U.S., we use Aon Securities LLC, an indirect, wholly owned subsidiary of Aon, and a U.S.-registered broker-dealer and investment advisor, member of FINRA and Securities Investor Protection Corporation, for investment banking, capital advisory services and other broker-dealer activities. Similar operations exist in other jurisdictions outside of the U.S.

Further, pension and financial laws and regulations, including oversight and supervision by the FCA in the U.K., the SEC and the DOL in the U.S., and regulators in other countries govern certain of the retirement-related consulting services provided by Aon and its subsidiaries and affiliates. This includes Aon subsidiaries that provide investment advisory services regulated by various U.S. federal authorities including the SEC, DOL, and FINRA, as well as authorities on the state level. In addition, other services provided by Aon and its subsidiaries and affiliates, such as trustee services and retirement and employee benefit program administrative services, are subject in various jurisdictions to pension, investment, securities, and insurance laws and regulations, and supervision.

Clientele

Our clients operate in many businesses and industries throughout the world. Our single largest client by revenue accounted for approximately 1% of our Total revenue in 2024. Additionally, we place insurance with many insurance carriers, none of which individually accounted for more than 10% of the total premiums we placed on behalf of our clients in 2024.

Aon United, Our Culture, and Human Capital Management Strategy

Our Culture

Our culture is driven by our values – committed as one firm to our purpose, united through trust and integrity as one inclusive team, and passionate about making our colleagues and clients successful. Our colleagues are the cornerstone of our success. Collaboration and innovation drive our culture, bringing the best of Aon to clients in a holistic and seamless manner. Our Aon United strategy defines how our colleagues work together to deliver value to clients, setting a new standard for client leadership. Aon United is brought to life through our common client value creation model which scales strategies from across the firm, through our Risk Capital and Human Capital solutions, to bring the best of Aon to clients. Each year, Aon makes significant philanthropic contributions to various organizations, supports numerous colleague volunteer opportunities, and

offers paid time off to volunteer. In 2023, we announced our 3x3 Plan to accelerate Aon United by delivering industry defining client content, unmatched capabilities, and exceptional service over three years.

Colleagues

As of December 31, 2024, we employed approximately 60,000 employees and conducted our operations in more than 120 countries. Our colleagues’ diverse talents, expertise, and insights contribute to the success of both our firm and our clients, and we seek to attract, grow, and retain the best talent in the industry. Our Inclusive People Leadership strategy is a central part of our Aon United strategy and is a key enabler to realizing our aspirations and purpose as a firm. All our colleagues are called upon to be leaders in embracing and modeling our Aon United values and behaviors. Inclusive People Leadership at Aon is designed to ensure that all colleagues – at every stage of their career journey – are equipped and motivated to deliver on our purpose and able to achieve their full potential. Our colleague experience ensures that colleagues feel more relevant, connected and valued which creates a greater sense of belonging.

Training and Development

We invest significant resources to develop the talent needed to remain at the forefront of innovation and remain an attractive employer. Colleagues are invited to complete a broad spectrum of curricula to meet their career stage goals and developmental needs. We provide our colleagues what they need to learn and grow to be best-in-class client leaders. From self-guided learning courses to advanced leadership programs, the curriculum is aligned to the Aon United strategy. Our investment in technology and use of virtual and in-person based learning and development programs allows us to deliver targeted offerings designed to advance all colleagues’ development.

Colleague Engagement and Retention

Providing an engaging and rewarding colleague experience is a top priority for us and understanding colleagues’ feedback helps us to reach that goal. We use a variety of channels to facilitate open, on-going, and direct communication with colleagues. These channels include open forums and town halls with executives, colleague surveys, and engagement through our Business Resource Groups. Business Resource Groups are our independent and voluntary networks that provide input, take action, and help identify opportunities for our firm to further commitments to inclusion, wellbeing, and belonging.

Our engagement survey process consists of frequent pulse surveys, as well as our annual all colleague support survey which enables us to understand how colleagues are engaging with their teams, the firm, and clients. This outreach effort allows us to gather insights more rapidly, take timely action to address feedback, and deliver on the needs of colleagues in real time – ensuring colleagues feel more connected, more valued and more relevant. The pulse surveys for 2024 were focused on topics such as manager and leadership support, delivering on our Aon Story, colleague wellbeing, inclusion, talent acquisition and performance and rewards. Feedback from our workforce provides management with a better understanding of evolving colleague viewpoints, and ensures we are taking appropriate steps to drive colleague engagement and retention. For discussion of the risks related to the attraction and retention of senior management and other professional personnel, see the “Risk Factors” section in Part I, Item 1A of this report.

Rewards

In addition to an inspired purpose and culture, we are proud to offer our colleagues a total rewards program that combines competitive pay, incentive opportunities, and benefits. Our compensation programs including salary, recognition, cash, and equity incentives are connected to our formal performance management and career development approach. These programs serve to reward colleagues for their Aon United impact both in what they accomplish for clients, colleagues, and shareholders, how they achieve those results and how they deliver on our values. We maintain a global commitment to colleague wellbeing and play a key role in supporting colleagues across the physical, emotional, financial, and social spectrum. Our comprehensive benefit programs are competitive for the markets in which we operate and aligned with our values and culture.

Our compensation philosophy aligns with our Aon United strategy and delivering long-term shareholder value creation. Our executive incentives are based on driving results, delivery of strategic initiatives, and leadership. Twenty percent of executive discretionary incentive compensation is based on quantifiable performance against strategic people priorities, including talent retention, engagement, wellbeing and inclusion.

Inclusion

We believe that inclusive teams produce better insight, better solutions and, ultimately, the best outcomes for clients and our long-term success.

We are focused on being a firm that is representative of the communities in which we operate. We aim to achieve this by aligning inclusion actions to the following pillars: recruitment, education, promotion, and representation. We strongly believe that only when colleagues can be their authentic selves will they reach their full potential.

The Company’s Board of Directors (“Board”) oversees Aon’s ERM program and allocates certain oversight responsibilities to its committees and any sub-committees, as appropriate. Our commitment to inclusion starts from the top with our the Board, including its Inclusion & Wellbeing Sub-Committee. Our Global Inclusive Leadership Council is sponsored by our Chief Executive Officer and Chief Administrative Officer. Our colleague-led Business Resource Groups also support execution and provide additional opportunities for colleagues to enhance our inclusive environment.

As of December 31, 2024, our global workforce was 54% women and 46% men, and the Aon Executive Committee, which leads the firm was 53% women and 47% men. At the manager level, 28% of senior leaders and 44% of managers with one or more direct report were women. New colleague hires for the year were 53% women and 47% men. Our U.S. workforce was 25% racially or ethnically diverse, calculated as a percentage of colleagues that have voluntarily disclosed their race or ethnicity to Aon. At the manager level, 12% of U.S. senior leaders and 18% of U.S. managers with one or more direct report were racially or ethnically diverse. New colleague hires for the year in the U.S. were 30% racially or ethnically diverse.

Apprenticeship Program

Apprenticeship programs help build a talent pipeline of highly skilled professionals while providing apprentices with advanced education and work experience. By removing some of the traditional barriers to entry-level employment, as a firm we can contribute to local workforce development and cultivate talent while improving retention rates in these entry-level roles. As a founding member of ten apprentice networks within the U.S., we partner with companies and organizations to assist them in building their own programs through sharing best practices and learnings. Across these networks, we have 249 organizations committed as of December 31, 2024.

Our two-year Apprenticeship Program, which was implemented in the UK and U.S. in 2012 and 2017, respectively, serves as an alternate route into a permanent role that normally requires a specific degree or professional experience. We provide motivated, high-potential individuals with the required training (on the job and in the classroom), professional skills development, mentorship, and experiential learning to bridge the gap. 802 Aon apprentices have been hired since the inception of the program across the U.S. and U.K. Both programs are certified apprenticeship programs, by the Department of Labor in the U.S. and the Department of Education in the U.K.

Website Access to Reports and Other Information

Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and all amendments to those reports are made available free of charge through our website (https://www.aon.com) as soon as reasonably practicable after such material is electronically filed with or furnished to the SEC. Also posted on our website are the charters for our Audit, Organization and Compensation, Governance/Nominating, and Finance Committees, and Inclusion & Wellbeing Sub-Committee, our Governance Guidelines, and our Code of Business Conduct. Within the time period required by the SEC and the NYSE, we will post on our website any amendment to or waiver of the Code of Business Conduct applicable to any executive officer or director. In addition, we may announce material information to investors and the marketplace using our investor relations website. While not all of the information that we post to such website is of a material nature, some information could be deemed to be material. Accordingly, we encourage investors, the media, and others interested in our company to review the information that we share on our investor relations page on www.aon.com. The information provided on our website is not part of this report and is therefore not incorporated herein by reference.

The risk factors set forth below reflect risks associated with our existing and potential businesses and the industries in which we operate generally and contain “forward-looking statements” as discussed in the “Business” Section of Part I, Item 1 of this report. Readers should consider these risks in addition to the other information contained in this report because our business, financial condition, or results of operations could be materially adversely affected if any of these risks were to actually occur and the occurrence of such risks could cause our actual results to differ materially from those stated in or implied by the forward-looking statements in this document and elsewhere.

Risk Factors Summary

The following is a summary of the principal risks associated with our businesses and the industries in which we operate generally as described in more detail in this report. We encourage you to carefully review the full risk factors immediately following this summary as well as the other information in this report.

Risks Related to Our Business

• An overall decline in economic and business activity could have a material adverse effect on the financial condition and results of operations of our business.

• We face significant competitive pressures from traditional and non-traditional competitors that could affect our business.

• If we are unable to effectively develop and implement innovative strategies, efficiencies and new solutions for our clients, our reputation, ability to compete effectively and financial condition may be adversely affected.

• If our clients are not satisfied with our services, we may face additional cost, loss of profit opportunities, damage to our reputation, or legal liability.

• Revenues from commission arrangements may fluctuate due to many factors, including cyclical or permanent changes in the insurance and reinsurance markets outside of our control.

• The profitability of our operations may not meet our expectations due to unexpected costs, cost overruns, inflation, early contract terminations, unrealized assumptions used in our contract bidding process or the inability to maintain our prices.

Financial Risks

• We are exposed to fluctuations in currency exchange rates that could negatively impact our financial results and cash flows. Similarly, changes in interest rates and deterioration of credit quality could reduce the value of our cash balances and investment portfolios and adversely affect our financial condition or results.

• We have debt outstanding that could adversely affect our financial flexibility. In addition, a decline in the credit ratings of our senior debt and commercial paper may adversely affect our borrowing costs, access to capital, and financial flexibility.

• Our tax assets and liabilities are subject to a variety of different factors, including the adoption and implementation of OECD tax proposals, which could create volatility in our global effective tax rate, expose us to greater than anticipated tax liabilities or cause us to adjust previously recognized tax assets and liabilities.

• We are a holding company and, therefore, may not be able to receive dividends or other payments in needed amounts from our subsidiaries.

Legal and Regulatory Risks

• We are subject to E&O claims against us as well as other contingencies and legal proceedings, some of which, if determined unfavorably to us, could have a material adverse effect on our financial condition or results of operations.

• Our businesses are subject to extensive governmental regulation, which could reduce our profitability, limit our growth, or subject us to legal and regulatory actions.

• Failure to protect our intellectual property rights, or allegations that we have infringed on the intellectual property rights of others, could harm our reputation, ability to compete effectively, and financial condition.

Operational Risks

• Natural or human-caused disasters could result in declines in business and increases in claims that could adversely affect our financial condition and results of operations.

• Our success depends on our ability to retain, attract and develop experienced and qualified personnel, including our senior management team and other personnel.

• We may not recognize all of the expected benefits from our Accelerating Aon United program and other operational improvement initiatives.

Risks Related to Technology, Cybersecurity, and Data Protection

• We rely on complex information technology systems and networks to operate our business. Any significant system or network disruption due to a breach in the security of our information technology systems could have a negative impact on our reputation, operations, sales, and operating results.

• Improper disclosure of confidential, personal, or proprietary data could result in regulatory scrutiny, legal liability, or harm to our reputation.

Risks Related to the Acquisition of NFP

• We may not be able to integrate the NFP business successfully or manage the combined business effectively, and many of the anticipated synergies and other benefits may not be realized or may not be realized within the expected time frame.

• We have incurred and may continue to incur significant integration-related costs in connection with the acquisition of NFP.

Risks Related to Being an Irish-incorporated Company

• We are incorporated in Ireland, and Irish law differs from the laws in effect in the U.S. and may afford less protection to holders of our securities.

• As an Irish public limited company, certain capital structure decisions regarding the Company will require the approval of shareholders, which may limit the Company’s flexibility to manage its capital structure.

• Irish law requires us to have available “distributable profits” to pay dividends to shareholders and generally to make share repurchases and redemptions.

Risks Related to Our Business

An overall decline in economic and business activity could have a material adverse effect on the financial condition and results of operations of our business.

The results of our operations are generally affected by the level of business activity of our clients, which in turn is affected by the economy of the industries and markets these clients serve. Economic downturns, volatility, or uncertainty in the broader economy or in specific markets (including as a result of endemics or pandemics, climate change, political unrest, actions by central banks, or otherwise) have caused in the past and may in the future cause reductions in technology and discretionary spending by our clients, which may result in reductions in the growth of new business or reductions in existing business. If our clients become financially less stable, enter bankruptcy, liquidate their operations or consolidate, our revenues and collectability of receivables could be adversely affected.

The demand for property and casualty insurance generally rises as the overall level of economic activity increases and generally falls as such activity decreases, affecting both the commissions and fees generated by our Risk Capital segment. The economic activity that impacts property and casualty insurance is most closely correlated with employment levels, corporate revenues, and asset values. Downward fluctuations in the year-over-year insurance premiums charged by insurers to protect against the same risk, referred to in the industry as softening of the insurance market, could adversely affect these businesses as a significant portion of the revenue is determined as a percentage of premiums charged to our clients. In addition, certain discretionary services within our business, such as our talent advisory services, project-related work within our Commercial Risk, Health, and Wealth solution lines, and transaction services, may see a decrease in activity if the overall level of economic activity results in a reduction to ou

Showing the first 8K of 96K characters. Open the full section

None.

Aon has from time-to-time experienced cybersecurity incidents. In the event of a cybersecurity incident, Aon responds in accordance with our policies, processes, applicable laws and regulations. When necessary, Aon also engages third parties, such as external cybersecurity advisors to investigate and remediate incidents. To date, the cybersecurity incidents have not had a material impact on our business strategy, results of operations, or financial condition, but we face risks from cybersecurity threats that, if realized, may materially affect us, including our business strategy, results of operations, or financial condition. For additional information regarding the risks from cybersecurity threats, please see the risk factors entitled “We rely on complex information technology systems and networks to operate our business. Any significant system or network disruption due to a breach in the security of our information technology systems could have a negative impact on our reputation, operations, sales, and operating results” and “Improper disclosure of confidential, personal, or proprietary data could result in regulatory scrutiny, legal liability, or harm to our reputation” in Part I, Item 1A of this report.

Aon strives to protect the personal and confidential data of our clients and our colleagues. To do so, Aon engages in a risk-based approach to adopting and implementing technical, organizational, administrative, and physical safeguards for cybersecurity. One key component to safeguard against risks facing Aon’s technology and security is Aon’s enterprise risk management (“ERM”) program. Aon’s management carries out the processes, controls, and practices of the Company’s ERM program, including the identification, assessment, prioritization, and mitigation of cybersecurity risks. Aon uses external service providers, where appropriate, to assess, test or otherwise assist with aspects of its security processes.

The Company’s Board oversees Aon’s ERM program and allocates certain oversight responsibilities to its committees and any sub-committees, as appropriate. The Board has delegated to the Audit Committee the primary responsibility for the oversight of the Company’s ERM program. The Audit Committee also has primary responsibility for the oversight of

cybersecurity risk and engages in regular discussion with management regarding cybersecurity and privacy risk mitigation and incident management. Cybersecurity matters are an important focus of our Board’s oversight of risk. The Company’s management, including the Chief Security Officer (“CSO”), regularly presents to the Audit Committee of the Board regarding cybersecurity matters. Members of senior management attend Board and committee meetings to address any questions or concerns raised by the Board related to risk management, including those relating to cybersecurity, and any other matters.

In addition, Aon maintains a Global Security Services (“GSS”) organization, led by the CSO, with dedicated security personnel responsible for protecting Aon’s people, property, and information. Aon’s CSO reports to Aon’s Chief Operating Officer and is an experienced technology and cybersecurity professional, with over 20 years’ experience in information security and technology.

The Company’s Global Emergency Operations Center (“GEOC”) serves as a single point of control, coordination, and communication for protecting Aon's people, property, and information. The GEOC is responsible for triage of all incidents pertaining to the confidentiality, integrity, and availability of customer data. The GEOC monitors threat intelligence reporting and receives alerts and reports from Aon colleagues and IT systems. In coordination with the Global Privacy Office (“GPO”) and GSS, the GEOC reports significant cybersecurity incidents to the Cyber Incident Governance Committee (“CIGC”).

The CIGC is comprised of members of management, and is responsible for reviewing significant cybersecurity incidents. The CIGC includes the CSO, the Chief Privacy and Data Trust Officer, and other representatives from the Company’s GPO and GSS, as well as leaders from the Company’s operations, Risk Management, Law & Compliance, Controllership, Internal Audit, and Communications functions. The CIGC reviews and assesses cybersecurity incidents and is responsible for coordinating the mitigation and remediation of such incidents.

The Company regularly conducts security scanning and reviews of regulatory IT controls. Additional security reviews may be triggered in connection with the assessment of new projects, business initiatives or third-party/supplier engagements. The Company’s Internal Audit function follows a risk-based approach to evaluating controls over key enterprise risks, including cybersecurity, as well as compliance with select regulations and corporate policies.

Aon has established a third-party risk governance program that creates guidelines for selecting and managing its suppliers, including assessing of their operational capabilities, adherence to the Company’s data security requirements, and technical, organizational, and physical safeguards. Contractual requirements and periodic reviews are designed to promote compliance with Aon’s security requirements. Aon’s GPO and Law & Compliance department work with business units to incorporate appropriate controls into supplier contracts.

The Company’s controls are designed to align to the National Institute of Standards and Technology (“NIST”) Cybersecurity Framework . This does not imply that we meet any particular technical standards, specifications or requirements at all times but that the aforementioned frameworks help us identify, assess, and manage cybersecurity risks relevant to our business.

We use the aforementioned risk-based approach to cybersecurity to promote accountability for all of our functions across our businesses as well as our third parties to monitor for and prevent any adverse consequences from cybersecurity risks. These risks are continuously evolving, and our program is designed to evaluate these risks on an ongoing basis.

We have offices in various locations throughout the world. Substantially all of our offices are located in leased premises. We maintain our corporate headquarters at 15 George's Quay, Dublin 2, Ireland, where we occupy approximately 33,000 square feet of space under an operating lease agreement that expires in 2044. The following are additional significant leased properties, along with the occupied square footage and expiration.

As leases expire, we do not anticipate difficulty in negotiating renewals or finding other satisfactory space if the premise becomes unavailable. We believe that the facilities we currently occupy are adequate for the purposes for which they are being used and are well maintained. In certain circumstances, we may have unused space and may seek to sublet such space to third parties, depending upon the demands for office space in the locations involved. As part of our AAU restructuring program, we are reducing our real estate footprint to align with our hybrid working strategy. See Note 9 “Lease Commitments” of the Notes

to Consolidated Financial Statements in Part II, Item 8 of this report for information with respect to our lease commitments as of December 31, 2024.

We hereby incorporate by reference Note 16 “Claims, Lawsuits, and Other Contingencies” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report.

Not applicable.

Information about our Executive Officers

The executive officers of Aon, as of February 18, 2025 unless otherwise noted, their business experience during a period of the last five years or longer, and their ages and positions held are set forth below.

PART II

Our class A ordinary shares, $0.01 nominal value per share, are traded on the NYSE under the trading symbol AON.

In February 2025, Aon paid a quarterly cash dividend of $0.675 per share. The declaration of future cash dividends is at the discretion of our Board of Directors and will depend upon our future earnings, liquidity, cash flows, capital allocation, financial conditions, and other factors.

On February 14, 2025 the last reported sale price of our ordinary shares as reported by the NYSE was $386.99 per share. We have approximately 483 holders of record of our class A ordinary shares as of February 18, 2025.

The following information relates to the repurchases of equity securities by Aon or any affiliated purchaser during each month within the fourth quarter of the fiscal year covered by this report:

(1)Does not include commissions paid to repurchase shares.

(2)The Repurchase Program was established in April 2012 with $5.0 billion in authorized repurchases and was increased by $5.0 billion in authorized repurchases in each of November 2014, June 2017, and November 2020, and by $7.5 billion in February 2022 for a total of $27.5 billion in repurchase authorizations.

Information relating to the compensation plans under which equity securities of Aon are authorized for issuance is set forth under Part III, Item 12 “Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters” of this report and is incorporated herein by reference.

We did not make any unregistered sales of equity in 2024.

EXECUTIVE SUMMARY OF 2024 FINANCIAL RESULTS

Aon plc is a leading global professional services firm providing a broad range of Risk Capital and Human Capital solutions. Through our experience, global reach, and comprehensive analytics, we help clients meet rapidly changing, increasingly complex, and interconnected challenges related to risk and people. We are committed to accelerating innovation to address unmet and evolving client needs so that our clients are better informed, better advised, and able to make better decisions to protect and grow their business. Management remains focused on strengthening Aon and uniting the firm with a portfolio of Risk Capital and Human Capital capabilities enabled by data and analytics and a united operating model to deliver additional insight, connectivity, and efficiency.

Financial Results

The following is a summary of our 2024 financial results:

• Revenue increased $2.3 billion, or 17%, to $15.7 billion, reflecting acquired revenues from NFP and 6% organic revenue growth, driven by net new business and ongoing strong retention. Risk Capital revenue increased $1.0 billion, or 10%, to $10.5 billion and Human Capital revenue increased $1.3 billion, or 35%, to $5.2 billion in 2024 compared to 2023.

• Operating expenses increased $2.3 billion, or 24%, to $11.9 billion in 2024 due primarily to the inclusion of NFP’s operating expenses, an increase in expense associated with 6% organic revenue growth, Accelerating Aon United restructuring charges, and transaction and integration costs, partially offset by $110 million of restructuring savings. Risk Capital operating expenses increased $647 million, or 10%, to $7.2 billion and Human Capital operating expenses increased $1.3 billion, or 47%, to $4.1 billion in 2024 compared to 2023.

• Operating margin decreased to 24.4% in 2024 from 28.3% in 2023, driven primarily by the addition of NFP and an increase in operating expenses as previously described, partially offset by organic revenue growth of 6% and $110 million of net restructuring savings. Risk Capital operating margin increased to 31.3% in 2024 from 30.9% in 2023 and Human Capital operating margin decreased to 21.9% in 2024 from 28.4% in 2023.

• Due to the factors set forth above, Net income was $2.7 billion in 2024, an increase of $92 million, or 4%, from 2023.

• Diluted earnings per share was $12.49 per share in 2024 compared to $12.51 per share in the prior year period.

• Cash flows provided by operating activities was $3.0 billion in 2024, a decrease of $400 million, or 12%, from $3.4 billion in 2023, primarily due to higher cash taxes, payments related to restructuring, legal settlement expenses, and transaction and integration costs, partially offset by strong adjusted operating income growth and working capital improvements.

We focus on four key metrics, that are not presented in accordance with U.S. GAAP that we communicate to shareholders: organic revenue growth, adjusted operating margin, adjusted diluted earnings per share, and free cash flow. These non-GAAP metrics should be viewed in addition to, not instead of, our Consolidated Financial Statements. The following is our measure of performance against these four metrics for 2024:

• Organic revenue growth, a non-GAAP measure defined under the caption “Review of Consolidated Results — Organic Revenue Growth,” was 6% in 2024, compared to 7% organic growth in the prior year period, driven by net new business and ongoing strong retention.

• Adjusted operating margin, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Operating Margin,” was 31.5% in 2024, compared to 31.6% in the prior year. The decrease in adjusted operating margin primarily reflects the addition of NFP and increased expenses, partially offset by 6% organic revenue growth and $110 million of net restructuring savings. Risk Capital adjusted operating margin increased to 34.6% in 2024 from 34.2% in 2023 and Human Capital adjusted operating margin decreased to 29.5% in 2024 from 29.9% in 2023.

• Adjusted diluted earnings per share, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Diluted Earnings per Share,” was $15.60 per share in 2024, an increase of $1.46 per share, or 10%, from $14.14 per share in 2023.

• Free cash flow, a non-GAAP measure defined under the caption “Review of Consolidated Results — Free Cash Flow,” was $2.8 billion in 2024, a decrease of $366 million, or 11%, from $3.2 billion in 2023, reflecting a decrease in Cash flows from operations, partially offset by a $34 million decrease in capital expenditures.

ENVIRONMENTAL, SOCIAL, AND GOVERNANCE

For many companies, the management of ESG risks and opportunities has become increasingly important, and ESG-related challenges, such as extreme weather events, supply chain disruptions, cyber events, regulatory changes, ongoing public health impacts, and the increased focus on workforce resilience in various work environments, continue to create volatility and uncertainty for our clients. At Aon, helping clients manage risk - including ESG risk - is at the core of what we do. We offer a wide range of risk assessment, consulting, and advisory solutions, many of which are significant parts of our core business offerings, designed to address and manage ESG issues for clients, and to enable our clients to create more sustainable value. We see significant opportunity in enhancing our impact and delivering innovative client solutions on ESG matters.

ACQUISITION OF NFP

On April 25, 2024, the Company completed its acquisition of NFP, a leading middle-market provider of property and casualty brokerage, benefits consulting, wealth management, and retirement plan consulting, with more than 7,700 colleagues. The Company acquired NFP Intermediate Holdings A Corp in a cash-and-stock merger for an aggregate U.S. GAAP preliminary purchase price totaling $9.1 billion, including approximately $3.2 billion to settle NFP indebtedness and cash consideration to the selling shareholders, and approximately 19 million class A ordinary shares with a fair value of approximately $5.9 billion, based on the Company’s closing stock price on April 25, 2024. In addition, the company had other adjustments of $3.9 billion for cash and certain assumed liabilities.

REVIEW OF CONSOLIDATED RESULTS

Summary of Results

Our consolidated results are as follows (in millions):

Showing the first 8K of 125K characters. Open the full section

We are exposed to potential fluctuations in earnings, cash flows, and the fair values of certain of our assets and liabilities due to changes in interest rates and foreign exchange rates. To manage the risk from these exposures, we enter into a variety of derivative instruments. We do not enter into derivatives or financial instruments for trading or speculative purposes.

The following discussion describes our specific exposures and the strategies we use to manage these risks. Refer to Note 2 “Summary of Significant Accounting Principles and Practices” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report for a discussion of our accounting policies for financial instruments and derivatives.

Foreign Exchange Risk

We are subject to foreign exchange rate risk. Our primary exposures include exchange rates between the U.S. dollar and the euro, the British pound, the Canadian dollar, the Australian dollar, the Indian rupee, and the Japanese yen. We use over-the-counter options and forward contracts to reduce the impact of foreign currency risk to our financial statements.

Additionally, some of our non-U.S. subsidiaries receive revenue in currencies that differ from their functional currencies. Most significantly, our U.K. subsidiaries earn a portion of their revenue in U.S. dollars, euro, and Japanese yen, but most of their expenses are incurred in British pounds. At December 31, 2024, we have hedged approximately 45% of our U.K. subsidiaries’ expected exposures to transactions denominated in U.S. dollar, euro, and Japanese yen for the years ending December 31, 2025 and 2026, respectively. We generally do not hedge exposures beyond two years.

We also use forward and option contracts to economically hedge foreign exchange risk associated with monetary balance sheet exposures, such as intercompany notes and current assets and liabilities that are denominated in a non-functional currency and are subject to remeasurement.

The translated value of revenues and expenses from our international brokerage operations are subject to fluctuations in foreign exchange rates. A strengthening U.S. dollar has an adverse impact on our Net income attributable to shareholders, which are reported in U.S. dollars in our Consolidated Financial Statements. If we were to hypothetically translate prior year results at current year exchange rates, diluted earnings per share would have an unfavorable $0.11 comparable impact during the year ended December 31, 2024. Further, adjusted diluted earnings per share, a non-GAAP measure as defined and reconciled under the caption “Review of Consolidated Results — Adjusted Diluted Earnings Per Share,” would have an unfavorable $0.12 comparable impact during the year ended December 31, 2024 if we were to hypothetically translate prior year results at current year exchange rates.

Interest Rate Risk

Our fiduciary investment income is affected by changes in international and domestic short-term interest rates. We monitor our net exposure to short-term interest rates and, as appropriate, hedge our exposure with various derivative financial instruments. This activity primarily relates to brokerage funds held on behalf of clients in the U.S. and in continental Europe. A decrease in global short-term interest rates adversely affects our fiduciary investment income. A hypothetical, instantaneous parallel decrease in the year-end yield curve of 100 BPS would cause a decrease, net of derivative positions, of $71 million to each of 2025 and 2026 pretax income. A corresponding increase in the year-end yield curve of 100 BPS would cause an increase, net of derivative positions, of $71 million to each of 2025 and 2026 pre-tax income.

We have long-term debt outstanding, excluding the current portion, with a fair market value of $15.3 billion and $9.2 billion as of December 31, 2024 and December 31, 2023, respectively. The fair value was less than the carrying value by $957 million at December 31, 2024, and $772 million less than the carrying value at December 31, 2023. A hypothetical 1% increase or decrease in interest rates would change the fair value by a decrease of 7% or an increase of 8%, respectively, at December 31, 2024.

We have selected hypothetical changes in foreign currency exchange rates, interest rates, and equity market prices to illustrate the possible impact of these changes; we are not predicting market events.

Report of Independent Registered Public Accounting Firm

To the Shareholders and the Board of Directors of Aon plc

Opinion on the Financial Statements

We have audited the accompanying consolidated statements of financial position of Aon plc (the Company) as of December 31, 2024 and 2023, the related consolidated statements of income, comprehensive income, shareholders’ equity (deficit) and cash flows for each of the three years in the period ended December 31, 2024, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024, in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February 18, 2025 expressed an unqualified opinion thereon.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the financial statements that were communicated or required to be communicated to the audit committee and that: (1) relate to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

Showing the first 8K of 243K characters. Open the full section

None.

Evaluation of Disclosure Controls and Procedures

We have conducted an evaluation of the effectiveness of the design and operation of our disclosure controls and procedures, as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) as of the end of the period covered by this annual report of December 31, 2024. Based on this evaluation, our Chief Executive Officer and Chief Financial Officer concluded as of December 31, 2024 that our disclosure controls and procedures were effective such that the information relating to Aon, including our consolidated subsidiaries, required to be disclosed in our SEC reports is recorded, processed, summarized and reported within the time periods specified in SEC rules and forms, and is accumulated and communicated to our management, including our Chief Executive Officer and Chief Financial Officer, as appropriate to allow timely decisions regarding required disclosure.

Management’s Report on Internal Control Over Financial Reporting

Management of Aon plc is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act. The Company’s internal control over financial reporting is designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with U.S. GAAP. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Under the supervision and with the participation of our senior management, including our Chief Executive Officer and Chief Financial Officer, we assessed the effectiveness of our internal control over financial reporting as of December 31, 2024. In making this assessment, we used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission in the Internal Control — Integrated Framework (2013 Framework). Based on this assessment, management has concluded our internal control over financial reporting was effective as of December 31, 2024.

On April 25, 2024, we completed our acquisition of NFP. We are in the process of assessing NFP’s internal controls over financial reporting and will make appropriate changes as NFP is integrated into the our internal controls over financial reporting. Management’s report on Internal Control Over Financial Reporting does not include the internal controls of NFP, which is included in the 2024 consolidated financial statements of the Company and constituted 3% of total assets, excluding the preliminary value of goodwill and other intangibles assets, as of December 31, 2024 and 11% of total revenue for the year then ended December 31, 2024.

The effectiveness of our internal control over financial reporting as of December 31, 2024 has been audited by Ernst & Young, LLP, the Company’s independent registered public accounting firm, as stated in their report included herein titled “Report of Independent Registered Public Accounting Firm-Opinion on Internal Control over Financial Reporting.”

Changes in Internal Control Over Financial Reporting

There were no changes, other than the acquisition of NFP, in our internal control over financial reporting (as defined in Rule 13a-15(f) under the Exchange Act) that occurred during the quarter ended December 31, 2024 that have materially affected, or that are reasonably likely to materially affect, our internal control over financial reporting.

Report of Independent Registered Public Accounting Firm

To the Shareholders and the Board of Directors of Aon plc

Opinion on Internal Control Over Financial Reporting

We have audited Aon plc’s internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework) (the COSO criteria). In our opinion, Aon plc (the Company) maintained, in all material respects, effective internal control over financial reporting as of December 31, 2024, based on the COSO criteria.

As indicated in the accompanying Management’s Report on Internal Control Over Financial Reporting, management’s assessment of and conclusion on the effectiveness of internal control over financial reporting did not include the internal controls of NFP, which is included in the 2024 consolidated financial statements of the Company and constituted 3% of Total assets, excluding the preliminary value of Goodwill and Other intangible assets, as of December 31, 2024 and 11% of Total revenue for the year then ended. Our audit of internal control over financial reporting of the Company also did not include an evaluation of the internal control over financial reporting of NFP.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated statements of financial position of the Company as of December 31, 2024 and 2023, the related consolidated statements of income, comprehensive income, shareholders' equity (deficit) and cash flows for each of the three years in the period ended December 31, 2024, and the related notes and our report dated February 18, 2025 expressed an unqualified opinion thereon.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Report on Internal Control Over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects.

Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

Definition and Limitations of Internal Control Over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Chicago, Illinois

February 18, 2025

Not applicable.

Not applicable.

PART III

Information relating to Aon’s directors is set forth under the heading “Proposal 1 — Resolutions Regarding the Election of Directors” in the Proxy Statement for the 2025 Annual General Meeting of Shareholders (the “Proxy Statement”) and is incorporated herein by reference. Information relating to Aon’s executive officers is set forth in Part I of this report and is incorporated herein by reference. The remaining information required by this item is set forth under the headings “Director Nominee Bios” and “Corporate Governance” in the Proxy Statement, and all such information is incorporated herein by reference.

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, and 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 this report. We will provide a copy of the code of ethics without charge upon request to the Company Secretary, 15 George’s Quay, Dublin 2, 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.

The Board has adopted an insider trading policy which is available on the Company’s website, described in the Company’s code of business conduct (which is also available on the Company’s website) and attached to this report as Exhibit 19.1. 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.

Information relating to director and executive officer compensation is set forth under the headings “Compensation Committee Report,” “Compensation Discussion and Analysis,” and “Executive Compensation” in the Proxy Statement, and all such information is incorporated herein by reference.

The material incorporated herein by reference to the information set forth under the heading “Compensation Committee Report” in the Proxy Statement shall be deemed furnished, and not filed, in this Form 10-K and shall not be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act as a result of this furnishing, except to the extent that it is specifically incorporated by reference by Aon.

Information relating to compensation committee interlocks and insider participation is set forth under the heading “Compensation Discussion and Analysis - Compensation Committee Interlocks and Insider Participation” in the Proxy Statement and is incorporated herein by reference.

Information relating to equity compensation plans and the security ownership of certain beneficial owners and management of Aon plc’s ordinary shares is set forth under the headings “Other Information - Equity Compensation Plan Information,” “Principal Holders of Voting Securities,” and “Security Ownership of Directors and Executive Officers” in the Proxy Statement, and all such information is incorporated herein by reference.

Information required by this Item is included under the headings “Corporate Governance — Director Independence” and “Certain Relationships and Related Transactions” in the Proxy Statement and is incorporated herein by reference.

Information required by this Item is included under the heading “Auditor Fees” in the Proxy Statement and is incorporated herein by reference.

PART IV

The following document has been included in Part II, Item 9.

All schedules for the Registrant and consolidated subsidiaries have been omitted because the required information is not present in amounts sufficient to require submission of the schedules or because the information required is included in the respective financial statements or notes thereto.

Showing the first 8K of 62K characters. Open the full section

None.

SIGNATURES

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

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.