UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

____________________________________________________________________________

FORM 10-K

(Mark One)
☒	ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
FOR THE FISCAL YEAR ENDED		DECEMBER 31, 2020
OR
☐	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

Commission file number: 1-7933

___________________________________________________________________________________________

Aon plc

(Exact name of registrant as specified in its charter)

IRELAND	98-1539969
(State or other jurisdiction of	(I.R.S. Employer
incorporation or organization)	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

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 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.

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. ☒

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 30, 2020, the aggregate market value of the registrant’s Class A Ordinary Shares held by non-affiliates of the registrant was $44,593,079,186 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 18, 2021: 225,984,346.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s proxy statement for its 2021 Annual General Meeting of Shareholders are incorporated by reference in this report in response to Part III, Items 10, 11, 12, 13, and 14.

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

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Class A Ordinary Shares, $0.01 nominal value	AON	New York Stock Exchange
Guarantees of Aon plc’s 4.00% Senior Notes due 2023	AON23	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 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

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, which are forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. Forward-looking statements represent management’s expectations or forecasts of future events. 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; the outcome of contingencies; dividend policy; the expected impact of acquisitions, dispositions, and other significant transactions, such as the Combination, as defined in Part I, Item 1 of this report; pension obligations; cash flow and liquidity; expected effective tax rate; 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 (the “SEC”), that could impact results include:

•changes in the competitive environment or damage to our reputation;

•fluctuations in currency exchange and interest 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, 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 us;

•the impact of legal proceedings and other contingencies, including those arising from errors and omissions and other claims against us;

•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 “U.K.”), the United States (the “U.S”). 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, including the withdrawal of the U.K. from the European Union (the “E.U.”)

•the failure to retain, attract and develop experienced and qualified personnel;

•international risks associated with our global operations;

•the effects of natural or man-made disasters, including the effects of the COVID-19 and other health pandemics;

•the potential for a system or network disruption or breach to result in operational interruption or improper disclosure of confidential, personal, or proprietary data;

•our ability to develop and implement new technology;

•damage to our reputation among clients, colleagues, markets or third parties;

3

•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 acting in a being responsible for making decisions on behalf of clients in our investment consulting business 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;

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

•our ability to implement initiatives intended to yield cost savings and the ability to achieve those cost savings;

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

•risks and uncertainties associated with the Combination, including our ability to obtain the requisite approvals of, to satisfy the other conditions to, or to otherwise complete, the Combination on the expected time frame, or at all, the occurrence of unanticipated difficulties or costs in connection with the Combination, our ability to successfully integrate the combined companies following the Combination and our ability to realize the expected benefits from the Combination.

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.

4

Table of Contents

PART I
	Item 1. Business
	Item 1A. Risk Factors
	Item 1B. Unresolved Staff Comments
	Item 2. Properties
	Item 3. Legal Proceedings
	Item 4. Mine Safety Disclosure
PART II
	Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities
	Item 6. Selected Financial Data
	Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations
	Item 7A. Quantitative and Qualitative Disclosures About Market Risk
	Item 8. Financial Statements and Supplementary Data
	Aon plc Consolidated Statements of Income
	Aon plc Consolidated Statements of Comprehensive Income
	Aon plc Consolidated Statements of Financial Position
	Aon plc Consolidated Statements of Shareholders' Equity
	Aon plc Consolidated Statements of Cash Flows
	Notes to Consolidated Financial Statements
	Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure
	Item 9A. Controls and Procedures
	Item 9B. Other Information
PART III
	Item 10. Directors, Executive Officers and Corporate Governance
	Item 11. Executive Compensation
	Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters
	Item 13. Certain Relationships and Related Transactions, and Director Independence
	Item 14. Principal Accountant Fees and Services
PART IV
	Item 15. Exhibits and Financial Statement Schedules
SIGNATURES

5

PART I

Item 1.    Business

OVERVIEW

Aon plc (which may be referred to as “Aon,” the “Company,” “we,” “us,” or “our”) is a leading global professional services firm that provides advice and solutions to clients focused on risk, retirement, and health, delivering distinctive client value via innovative and effective risk management and workforce productivity solutions that are under-pinned by industry-leading data and analytics. Our strategy is to be the preeminent professional services firm in the world, focused on risk and people.

Our clients are globally diversified and include all market segments and almost every industry in over 120 countries and sovereignties. 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 based upon return on invested capital.

On March 9, 2020, Aon and Willis Towers Watson Public Limited Company, an Irish public limited company (“WTW”), entered into a Business Combination Agreement with respect to a combination of the parties (the “Combination”). At the effective date of the Combination, WTW shareholders will be entitled to receive 1.08 newly issued Class A ordinary shares of Aon in exchange for each ordinary share of WTW held by such holders. Aon expects to close the Combination in the first half of 2021, subject to regulatory approval and customary closing conditions.

IRELAND REORGANIZATION

On April 1, 2020, a scheme of arrangement under English law was completed pursuant to which the Class A ordinary shares of Aon plc, a public limited company incorporated under the laws of England and Wales and the publicly traded parent company of the Aon group (“Aon Global Limited”), were cancelled and the holders thereof received, on a one-for-one basis, Class A ordinary shares of Aon plc, an Irish public limited company formerly known as Aon Limited (“Aon plc”) , as described in the proxy statement filed with the SEC on December 20, 2019 (the “Ireland Reorganization”). Aon plc is a tax resident of Ireland. References in this report to “Aon,” the “Company,” “we,” “us,” or “our” for time periods prior to April 1, 2020 refer to Aon Global Limited. References in the Financial Statements to “Aon,” the “Company,” “we,” “us,” or “our” for time periods on or after April 1, 2020, refer to Aon plc.

BUSINESS SEGMENT

The Company operates as one segment that includes all of Aon’s continuing operations, which, as a global professional services firm, provides advice and solutions to clients focused on risk, retirement, and health through five principal products and services: Commercial Risk Solutions, Reinsurance Solutions, Retirement Solutions, Health Solutions, and Data & Analytic Services. Collectively, these products and service lines make up our one segment: Aon United. In addition, the Company is continuing to expand on Aon United growth initiatives through its New Ventures Group.

In 2020, our consolidated total revenue was $11,066 million. This includes $4,690 million in Commercial Risk Solutions, $1,814 million in Reinsurance Solutions, $1,753 million in Retirement Solutions, $1,655 million in Health Solutions, and $1,171 million in Data & Analytic Services, before intercompany eliminations.

Principal Products and Services

Commercial Risk Solutions includes retail brokerage, cyber solutions, global risk consulting, and captives. In retail brokerage, our team of expert risk advisors applies a client-focused approach to commercial risk products and services that leverage Aon’s global network of resources, industry-leading data and analytics, and specialized expertise. Cyber solutions is one of the industry’s premier resources in cyber risk management. Our strategic focus extends to identify and protect critical digital assets supported by best-in-class transactional capabilities, enhanced coverage expertise, deep carrier relationships, and incident response expertise. Global risk consulting is a world-leading provider of risk consulting services supporting clients to better understand and manage their risk profile through identifying and quantifying the risks they face. We assist clients with the selection and implementation of the appropriate risk transfer, risk retention, and risk mitigation solutions, and ensure the continuity of their operations through claims consulting. Captives is a leading global captive insurance solutions provider that manages over 1,100 insurance entities worldwide including captives, protected segregated and incorporated cell facilities, as well as entities that support insurance-linked securities and specialist insurance and reinsurance companies.

6

Reinsurance Solutions includes treaty and facultative reinsurance 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. 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.

Retirement Solutions includes core retirement, investment consulting, and human capital. Retirement consulting specializes in providing organizations across the globe with strategic design consulting on their retirement programs, actuarial services, and risk management, including pension de-risking, governance, integrated pension administration, and legal and compliance consulting. Investment consulting provides public and private companies and other institutions with advice on developing and maintaining investment programs across a broad range of plan types, including defined benefit plans, defined contribution plans, endowments, and foundations. Within investment consulting, our delegated investment solutions offer ongoing management of investment programs and fiduciary responsibilities either in a partial or full discretionary model for multiple asset owners. It partners with clients to deliver our scale and experience to help them effectively manage their investments, risk, and governance and potentially lower costs. Human capital delivers advice and solutions that help clients accelerate business outcomes by improving the performance of their people including, assessment, optimized deployment, and the design, alignment, and benchmarking of compensation to business strategy and performance outcomes.

Health Solutions includes health and benefits brokerage and health care exchanges. Health and benefits brokerage partners with employers to develop innovative, customized benefits strategies that help manage risk, drive engagement, and promote accountability. Our private health exchange solutions help employers transform how they sponsor, structure, and deliver health benefits by building and operating a cost effective alternative to traditional employee and retiree health care. We seek outcomes of reduced employer costs, risk, and volatility, alongside greater coverage and plan choices for individual participants.

Data & Analytic Services includes Affinity, Aon Inpoint, CoverWallet, and ReView. Affinity specializes in developing, marketing and administering customized insurance programs and specialty market solutions for Affinity organizations and their members or affiliates. Aon Inpoint draws on the Global Risk Insight Platform, one of Aon’s proprietary databases, and is dedicated to making insurers, reinsurers. and other financial services participants more competitive by providing data, analytics, engagement, and consulting services. CoverWallet is a leading digital insurance platform for small- and medium-sized businesses dedicated to delivering exceptional client experiences to new and existing clients by leveraging data and analytics and a technology-enabled operating model to provide choice, transparency and convenience. ReView draws on another Aon proprietary database and broker market knowledge to provide advisory services, analysis, and benchmarking to help reinsurers more effectively meet the needs of cedents through the development of more competitive, innovative, and efficient risk transfer options.

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.

Fiduciary Funds

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 earn interest on these accounts.

Competition

Our business operates in a highly competitive and fragmented environment. We compete with other global insurance brokers and consulting companies, including Marsh & McLennan Companies, Inc., WTW, and Arthur J Gallagher & Company, as well as numerous other global specialist, regional, and local firms in almost every area of our business. We also compete

7

with insurance and reinsurance companies that 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, and financial services firms.

Seasonality

Due to buying patterns and delivery of certain products 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 countries and states in the U.S. in which our operating subsidiaries conduct business may require individual or company licenses to act as producers, brokers, agents, third-party administrators, managing general agents, reinsurance intermediaries, or adjusters. Under the laws of most countries and states, regulatory authorities have relatively broad discretion with respect to granting, renewing, and revoking producers’, brokers’, and agents’ licenses to transact business in the country or state. The operating terms may vary according to the licensing requirements of the particular country or state, which may require, among other things, that a firm operates in the country or state through a local corporation. In a few countries and states, licenses may be issued only to individual residents or locally owned business entities. In such cases, our subsidiaries either have such licenses or have arrangements with residents or business entities licensed to act in the country or state.

Our subsidiaries must comply with laws and regulations of the jurisdictions in which they do business. These laws and regulations are enforced by the Financial Conduct Authority (“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 the Financial Industry Regulatory Authority (“FINRA”) and Securities Investor Protection Corporation, for capital management transaction and 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 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 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. No one client accounted for more than 2% of our consolidated total revenues in 2020. 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 2020.

8

Human Capital Management

Aon United, Our Culture and Human Capital Strategy

Our colleagues are the cornerstone of Aon's success. Collaboration and innovation drive our culture, bringing the best of Aon to clients in a holistic and seamless manner. We approach every aspect of our business based on our Aon United Blueprint. Colleagues are trained upon hire under our Aon Impact Model, which supports the belief that businesses thrive when the people they serve flourish. The model sets behavioral expectations, embracing Aon's diverse capabilities, and shared cultural values to ensure colleagues are contributing towards a distinctive, high-performing, and inclusive Aon United culture.

Colleagues

As of December 31, 2020, we employed approximately 50,000 employees and conducted our operations in more than 120 countries and sovereignties. We know that 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 Colleague Mission is a central part of our Aon United Blueprint and is a key enabler to realizing our aspirations and purpose as a firm. We are committed to building thriving teams with the brightest talent, providing them opportunities to grow, rewarding them for their contributions, and supporting their journey to become the person and professional they want to be.

Pandemic Response

In 2020, we shifted the vast majority of our colleagues to remote work in response to the COVID-19 pandemic. The historic steps we’ve taken to build our Aon Business Services platform were instrumental in our response. Acting early, we began offering tools and services for enabling remote work and avoiding disruption in client service while emphasizing our commitment to colleague health and well-being. Our programs and policies on flexible work, leadership development, learning, telemedicine, childcare, sick leave, social and emotional health, rapidly evolved to meet the new normal and create a “new better” for our colleagues based on where they live and work.

Training and Development

We invest significant resources to develop the talent needed to remain at the forefront of innovation and make Aon an attractive employment destination. To make sure colleagues are on the right track for their career path, colleagues complete a variety of curricula to meet their career stage goals. We provide our colleagues what they need to learn, grow, and become the leaders our clients seek, and our communities need. From self-guided Aon University courses to our Leading Aon United and advanced learning programs, the curriculum is aligned to the Aon United Blueprint and the four expectations of the Aon Impact Model: Create Client Value, Develop Teams, Enable Innovation, and Deliver Business Results. Our use of virtual based learning and development programs during the COVID-19 pandemic has allowed us to continue these efforts despite most of our workforce being virtual during 2020.

Colleague Engagement and Retention

Providing an engaging and rewarding colleague experience is a top priority for our firm and understanding colleagues’ feedback helps us reach that goal. We use a variety of channels to facilitate open, on-going, and direct communication, including open forums with executives, pulse check surveys, and engagement through our Business Resource Groups, which are our independent, voluntary, non-profit associations that provide input, take action, and help identify opportunities for our firm to further its diversity, equity and inclusion commitments. In response to the challenging events of 2020, we updated our engagement survey process by offering more frequent pulse check surveys to understand how colleagues are engaging with their teams, the firm, and clients, so we can gather insights more rapidly and take timely action to address feedback. The pulse check surveys for 2020 have been focused on topics such as manager and leadership support, especially in how we serve clients; colleague well-being, inclusion and diversity; and the Aon United Blueprint. This feedback provides management 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 Part I, Item 1A. “Risk Factors” in 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, connect to our formal performance management and career development approach and serve to reward colleagues for their impact both in what they accomplish for clients, colleagues, and shareholders and how they achieve those results. We maintain a global commitment to colleague well-being 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.

9

Inclusion and Diversity

A diverse and inclusive workforce is a business imperative and key to Aon’s long-term success. We emphasize the recruitment, hiring, development, and retention of diverse talent, including women and underrepresented groups. To recruit and hire a diverse community of the best talent, we’ve built partnerships with a wide range of organizations, schools, and universities, and we specifically source talent from diverse communities. Aon is committed to creating a workplace environment that fosters mutual dignity, respect, and equal employment opportunity. We have formal initiatives and policies designed to promote an inclusive workplace free of discrimination and harassment, where colleagues are treated and compensated fairly and equitably. Along with policies and initiatives, we encourage colleague input and action to make sure we create the diverse and inclusive workplace to which we aspire. The commitment starts at the top with our Board of Directors and the standing Inclusion and Diversity Sub-Committee of the Board. Our Global Inclusive Leadership Council is chaired by our Chief Executive Officer and Chief People Officer. Regional Inclusive Leadership Councils and colleague-led Business Resource Groups support execution and provide additional opportunities for colleagues to lead the firm to achieve a truly inclusive environment. We are focused on being a firm that is representative of the communities in which we operate. We believe diversity drives insight, and that by giving all talent a voice, we are encouraging the development of top talent that will produce the best outcomes for clients.

Our Apprenticeship Program

Apprenticeship programs help build a talent pipeline of highly skilled and diverse professionals while providing apprentices with advanced education and work experience. By removing some of the traditional barriers to entry-level employment, Aon can contribute to local workforce development and cultivate talent while improving retention rates in these entry-level roles.

Aon's two-year Apprenticeship Program, which was implemented in the U.S. and U.K. in 2017 and 2012, respectively, serves as an alternate route into a permanent role that normally requires a specific degree or professional experience by providing 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. Over 290 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. In 2020 we announced our commitment to expand this program to include additional U.S. cities outside of Chicago's metropolitan area to the following six metropolitan areas hiring over 100 apprentices: Houston, Minneapolis, New York, Philadelphia, San Francisco, and Washington, DC.

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 (http://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, Compliance, Organization and Compensation, Governance/Nominating, Finance, and Inclusion & Diversity Committees, our Governance Guidelines, and our Code of Business Conduct. Within the time period required by the SEC and the New York Stock Exchange (“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 at our investor relations link located at the bottom of the 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.

Item 1A.    Risk Factors

Risk Factors Summary

The risk factors set forth below reflect risks associated with our businesses and the industries in which we operate generally. Some of the more significant risk factors are summarized below.

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.

•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.

10

•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.

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.

•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 global effective tax rate is subject to a variety of different factors, which could create volatility in that 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.

Operational Risks

•Our results of operations have been adversely affected and could be materially adversely affected in the future by the COVID-19 global pandemic.

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

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 Combination

•The Combination is subject to customary closing conditions, including conditions related to regulatory approvals, and may not be completed on a timely basis, or at all, or may be completed on a basis that has a material impact on the value of the combined company. Failure to close the Combination could negatively impact our share price and future business and financial results.

•While the Combination is pending, we are subject to business uncertainties related to our relationships with employees, clients and suppliers, which could adversely affect our business and operations. These uncertainties could also adversely affect the combined company following the Combination.

Risks Related to Being a Non-U.S. 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.

Risk Factors

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

11

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.

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 may 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 Commercial Risk Solutions, Reinsurance Solutions, and Data and Analytic Service lines. 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 earnings are determined as a percentage of premiums charged to our clients. Insolvencies and consolidations associated with an economic downturn, especially insolvencies in the insurance industry, could adversely affect our brokerage business through the loss of clients by hampering our ability to place insurance and reinsurance business. Also, error and omission claims against us, which we refer to as E&O claims, may increase in economic downturns, also adversely affecting our business.

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

As a global professional services firm, we compete with global, national, regional, and local insurance companies that market and service their own products, other financial services providers, brokers, and investment managers, independent firms, and consulting organizations affiliated with accounting, information systems, technology, and financial services firms. We compete with respect to service, delivery of insights, product features, price, commission structure, technology, financial strength, ability to access certain insurance markets, and name recognition. Our competitors may have better financial, technical and marketing resources, broader customer bases, greater name recognition, more comprehensive products, stronger presence in certain geographies, or more established relationships with their customers and suppliers than we have.

In addition, alliances among competitors or mergers of competitors could affect our market share, and some of our competitors may have or may develop a lower cost structure, adopt more aggressive pricing policies, or provide services that gain greater market acceptance than the services that we offer or develop.

Our competitors may be more successful in innovating and delivering services to meet new and existing client needs. Competitors may be able to respond to the need for technological changes, innovate faster, respond better to evolving client demand and industry conditions, or price their services more aggressively than we do. They may also compete for skilled professionals, finance acquisitions, fund internal growth, and compete for market share more effectively than we do. Further, new and non- traditional competitors, our clients’ increasing ability and determination to self-insure, and capital market alternatives to traditional insurance and reinsurance markets cause additional forms of competition and innovation that could affect our market share. This competition is further intensified by an industry trend where clients engage multiple brokers to service different portions of their accounts. If we fail to respond successfully to the to the evolving competition we face, our financial condition or results of operations might 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.

We depend, to a large extent, on our relationships with our clients and our reputation for high-quality advice and solutions. If a client is not satisfied with our services, it could cause us to incur additional costs and impair profitability, or lose the client relationship altogether. Moreover, if we fail to meet our contractual obligations, we could be subject to legal liability or loss of client relationships.

The nature of much of our work involves assumptions and estimates concerning future events, the actual outcome of which we cannot know with certainty in advance. For example, in our investment consulting business, we may be measured based on our track record regarding judgments and advice on investments that are susceptible to influences unknown at the time the advice was given. In addition, we could make computational, software programming, or data entry or management errors. A client may claim it suffered losses due to reliance on our consulting advice, which poses risks of liability exposure and costs of defense and increased insurance premiums. Many of our clients are businesses that actively share information among themselves about the quality of service they receive from their vendors. Accordingly, poor service to one client may negatively impact our relationships with multiple other clients.

12

Damage to our reputation could have a material adverse effect on our business.

We advise our clients on and provide services related to a wide range of subjects and our ability to attract and retain clients is highly dependent upon the external perceptions of our level of service, trustworthiness, business practices, financial condition, and other subjective qualities. Negative perceptions or publicity regarding these matters or others could erode trust and confidence and damage our reputation among existing and potential clients and existing and future employees, which could make it difficult for us to attract new clients and employees and retain existing ones. Negative public opinion could also result from actual or alleged conduct by us or those currently or formerly associated with us. Damage to our reputation could affect the confidence of our clients, rating agencies, regulators, stockholders, employees and third parties in transactions that are important to our business adversely affecting our business, financial condition, and operating results.

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.

Revenues from commission arrangements have historically been affected by significant fluctuations arising from uncertainties and changes in the industries in which we operate. A significant portion of our revenue consists of commissions paid to us out of the premiums that insurers and reinsurers charge our clients for coverage. We have no control over premium rates, and our revenues and profitability are subject to change to the extent that premium rates fluctuate or trend in a particular direction. The potential for changes in premium rates is significant, due to pricing cyclicality in the commercial insurance and reinsurance markets.

In addition to movements in premium rates, our ability to generate premium-based commission revenue may be challenged by:

•the growing availability of alternative methods for clients to meet their risk-protection needs, including a greater willingness on the part of corporations to “self-insure,” the use of so-called “captive” insurers, and the development of capital markets-based solutions and other alternative capital sources for traditional insurance and reinsurance needs that increase market capacity, increase competition, and put pressure on pricing;

•fluctuation in the need for insurance;

•the level of compensation, as a percentage of premium, that insurance carriers are willing to compensate brokers for placement activity;

•the growing desire of clients to move away from variable commission rates and instead compensate brokers based upon flat fees, which can negatively impact us as fees are not generally indexed for inflation and do not automatically increase with premium as does commission-based compensation; and

•competition from insurers seeking to sell their products directly to consumers, including online sales, without the involvement of an insurance broker

•growing number of technology-enabled competitors offering new risk-transfer solutions that eliminate the traditional broker-client relationship in both commercial insurance and reinsurance markets

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

Our profitability with respect to consulting engagements is highly dependent upon our ability to control our costs and improve our efficiency. As we adapt to changes in our business and the market, adapt to the regulatory environment, enter into new engagements, acquire additional businesses, and take on new employees in new locations, we may not be able to manage our large, diverse and changing workforce, control our costs, or improve our efficiency.

Our profit margin, and therefore our profitability, is largely a function of the rates we are able to charge for our services and the staffing costs for our personnel. Accordingly, if we are not able to maintain the rates we charge for our services or appropriately manage the staffing costs of our personnel, we may not be able to sustain our profit margin and our profitability will suffer. The prices we are able to charge for our services are affected by a number of factors, including competitive factors, the extent of ongoing clients’ perception of our ability to add value through our services, and general economic conditions. If we cannot drive suitable cost efficiencies, our profit margins will suffer. Our cost efficiencies may also be impacted by factors such as our ability to transition consultants from completed projects to new assignments, our ability to secure new consulting engagements, our ability to forecast demand for consulting services (and, consequently, appropriately manage the size and location of our workforce), employee attrition, and the need to devote time and resources to training and professional and business development.

13

In our investment consulting business, we advise or act on behalf of clients regarding their investments. The results of these investments are uncertain and subject to numerous factors, some of which are within our control and some which are not. Clients that experience losses or lower than expected investment returns may leave us for competitors and/or assert claims against us.

Our investment consulting business provides advice to clients on: investment strategy, which can include advice on setting investment objectives, asset allocation, and hedging strategies; selection (or removal) of investment managers; the investment in different investment instruments and products; and the selection of other investment service providers such as custodians and transition managers. For some clients, we are responsible for making decisions on these matters and we may implement such decisions in a fiduciary or agency capacity without assuming title over the underlying funds or assets invested. Asset classes may experience poor absolute performance and third parties we recommend or select, such as investment managers, may underperform their benchmarks due to poor market performance, negligence, or other reasons, resulting in poor investment returns or losses. These losses may be attributable in whole or in part to failures on our part or to events entirely outside of our control, including but not limited to uncertainty or volatility in financial markets due to economic, political, and regulatory conditions or pandemics. Plaintiffs have, and may continue to, file individual and class action lawsuits alleging investment consultants have charged excessive fees, given improper advice due to conflicts of interest, or recommended investments that underperformed other investments available at the time. Defending against these claims can involve potentially significant costs, including legal defense costs, as well as cause substantial distraction and diversion of other resources. If any lawsuit – against the Company or any other investment consultant – results in a large adverse verdict, the size of the verdict or resultant negative adverse publicity may prompt the filing of additional lawsuits. Furthermore, our ability to limit our potential liability is restricted in certain jurisdictions and in connection with claims involving breaches of fiduciary or agency duties or other alleged errors or omissions.

The anticipated benefits of the redomiciliation from the U.K. to Ireland may not be realized.

In April 2020, we changed the jurisdiction of incorporation for our parent company from the U.K. to Ireland by means of a scheme of arrangement under English law (the “Reorganization”). At the time of the Reorganization we expected, and we continue to expect, that the Reorganization will, among other things, provide greater certainty around ongoing access to existing U.S. treaties with other EU member countries from which we derive benefit. However, we may not realize the benefits we anticipate from the Reorganization, which could have an adverse effect on our business.

Financial Risks

We are exposed to fluctuations in currency exchange rates that could negatively impact our financial results and cash flows.

We face exposure to adverse movements in exchange rates of currencies other than our reporting currency, the U.S. dollar, as a significant portion of our business is located outside of the U.S. These exposures may change over time, and they could have a material adverse impact on our financial results and cash flows. Approximately 55% of our consolidated revenue is non-U.S., attributed on the basis of where the services are performed, and the exposures created can have significant currency volatility. These currency exchange fluctuations create risk in both the translation of the financial results of our global subsidiaries into U.S. dollars for our consolidated financial statements, as well as in those of our operations that receive revenue and incur expenses other than in their respective local currencies, which can reduce the profitability of our operations based on the direction the respective currencies’ exchange rates move. A decrease in the value of certain currencies relative to other currencies could place us at a competitive disadvantage compared to our competitors that benefit to a greater degree from a specific exchange rate move and can, as a result, deliver services at a lower cost or receive greater revenues from such a transaction. Although we use various derivative financial instruments to help protect against certain adverse foreign exchange rate fluctuations, we cannot eliminate such risks, and, as a result, changes in exchange rates may adversely affect our results. For example, the strengthening of the value of the U.S. dollar versus other currencies might adversely affect the value of our products and services when translated to U.S. dollar, even if the value of such products and services has not changed in their original currency.

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.

Operating funds available for corporate use were $1,192 million at December 31, 2020 and are reported in Cash and cash equivalents and Short-term investments. Of the total balance, $102 million was restricted to its use as of December 31, 2020. Funds held on behalf of clients and insurers were $5.7 billion at December 31, 2020 and are reported in Fiduciary assets. We also carry an investment portfolio of other long-term investments. As of December 31, 2020, these long-term investments had a carrying value of $74 million. Adverse changes in interest rates, performance, and counterparty credit quality, including default, could reduce the value of these funds and investments, thereby adversely affecting our financial condition or results. We may experience reduced investment earnings on our cash and short-term investments of fiduciary and operating funds if the yields on investments deemed to be low risk remain at or near their current low levels or fall below their current levels, or if negative yields on deposits or investments are experienced, as we have experienced in Japan and certain jurisdictions in the E.U. On the other hand, higher interest rates could result in a higher discount rate used by investors to value our future cash flows thereby resulting in a lower valuation of the Company. In addition, during times of stress in the banking industry, counterparty risk can quickly escalate, potentially resulting in substantial losses for us as a result of our cash or other investments with such counterparties, as well as substantial losses for our clients and the insurance companies with which we work.

14

Our pension obligations and value of our pension assets could adversely affect our shareholders’ equity, net income, cash flow, and liquidity.

To the extent that the pension obligations associated with our pension plans continue to exceed the fair value of the assets supporting those obligations, our financial position and results of operations may be adversely affected. In particular, lower interest rates and investment returns could result in the present value of plan liabilities increasing at a greater rate than the value of plan assets, resulting in higher unfunded positions in our pension plans. In addition, the periodic revision of pension assumptions or variances of actual results from our assumptions can materially change the present value of expected future benefits, and therefore the funded status of the plans and resulting net periodic pension expense. As a result, we may experience future changes in the funded status of our plans that could require us to make additional cash contributions beyond those that have been estimated and which could adversely affect shareholders’ equity, net income, cash flow and liquidity.

Our worldwide pension plans are significant, and therefore our pension contributions and expense are sensitive to various market, demographic, and other factors. These factors include equity and bond market returns, fair value of pension assets, the assumed interest rates we use to discount our pension liabilities, foreign exchange rates, rates of inflation, mortality assumptions, potential regulatory and legal changes or developments, and counterparty exposure from various investments and derivative contracts, including annuities. Variations or developments in connection with any of these factors could cause significant changes to our financial position and results of operations from year to year. In addition, contributions are generally based on statutory requirements and local funding practices, which may differ from measurements under U.S. Generally Accepted Accounting Principles (“U.S. GAAP”).

We have debt outstanding that could adversely affect our financial flexibility.

As of December 31, 2020, we had total consolidated debt outstanding of approximately $7.7 billion. The level of debt outstanding could adversely affect our financial flexibility by reducing our ability to use cash from operations for other purposes, including working capital, dividends to shareholders, share repurchases, acquisitions, capital expenditures and general corporate purposes. We also are subject to risks that, at the time any of our outstanding debt matures, we will not be able to retire or refinance the debt on terms that are acceptable to us, or at all.

As of December 31, 2020, we had two committed credit facilities outstanding. Each of these facilities is intended to support our commercial paper obligations and our general working capital needs. In addition, each of these facilities included customary representations, warranties, and covenants, including financial covenants that require us to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to adjusted consolidated EBITDA, tested quarterly.

A substantial portion of our outstanding debt, including certain intercompany debt obligations, contains financial and other covenants. The terms of these covenants may limit our ability to obtain, or increase the costs of obtaining, additional financing to fund working capital, capital expenditures, acquisitions, or general corporate requirements. This in turn may have the impact of reducing our flexibility to respond to changing business and economic conditions, thereby placing us at a relative disadvantage compared to competitors that have less indebtedness, or fewer or less onerous covenants associated with such indebtedness, and making us more vulnerable to general adverse economic and industry conditions.

If we cannot service our indebtedness, we may have to take actions such as selling assets, seeking additional equity, or reducing or delaying capital expenditures, strategic acquisitions, investments, and alliances, any of which could impede the implementation of our business strategy or prevent us from entering into transactions that would otherwise benefit our business. Additionally, we may not be able to take such actions or refinance any of our debt, if necessary, on commercially reasonable terms, or at all.

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.

A downgrade in the credit ratings of our senior debt and commercial paper could increase our borrowing costs, reduce or eliminate our access to capital, reduce our financial flexibility, and limit our ability to implement on corporate strategy. Our senior debt ratings at December 31, 2020 were A- with a stable outlook (Standard & Poor’s, or “S&P”), BBB+ with a negative outlook (Fitch, Inc., or “Fitch”), and Baa2 with a stable outlook (Moody’s Investor Services, or “Moody’s”). Our commercial paper ratings were A-2 (S&P), F-2 (Fitch) and P-2 (Moody’s).

Real or anticipated changes in our credit ratings will generally affect any trading market for, or trading value of, our securities. Such changes could result from any number of factors, including the modification by a credit rating agency of the criteria or methodology it applies to particular issuers, a change in the agency’s view of us (currently or as a combined company after the closing of the transaction with WTW) or our industry, or as a consequence of actions we take to implement our corporate strategies. A change in our credit rating could adversely limit our access to capital and our competitive position.

Our global effective tax rate is subject to a variety of different factors, which could create volatility in that tax rate, expose us to greater than anticipated tax liabilities or cause us to adjust previously recognized tax assets and liabilities.

We are, and anticipate we will be, subject to income taxes in Ireland, the U.K., the U.S. and many other jurisdictions. As a result, our global effective tax rate from period to period can be affected by many factors, including changes in tax legislation or regulations, the continuing development of regulations and other governmental action that affect the application of such legislation, our global mix of earnings, the use of global funding structures, the tax characteristics of our income, the effect of

15

complying with transfer pricing requirements under laws of many different countries on our revenues and costs, the consequences of acquisitions and dispositions of businesses and business segments. In addition, we could be subject to increased taxation as a result of changes in eligibility for the benefits of current income tax treaties between and among Ireland, the U.K., the U.S and other countries, including any future amendments to the current income tax treaties between and among such countries, or any new statutory or regulatory provisions that might limit our ability to take advantage of any such treaties. Significant judgment is required in determining our worldwide provision for income taxes, and our determination of the amount of our tax liability is always subject to review by applicable tax authorities. Our actual global tax rate may vary from our expectation and that variance may be material.

We are, and anticipate we will be, subject to tax audits conducted by Ireland, the U.K., the U.S., and other tax authorities, and the resolution of such audits could impact our tax rate in future periods, as would any reclassification or other changes (such as those in applicable accounting rules) that increases the amounts we have provided for income taxes in our consolidated financial statements. The tax laws and regulations in Ireland, the U.K., the U.S., and the other tax jurisdictions in which the we operate are inherently complex, and we will be obligated to make judgments and interpretations about the application of these laws and regulations to our operations and businesses. The interpretation and application of these laws and regulations could be challenged by the relevant governmental authorities, which could result in administrative or judicial procedures, actions or sanctions, which could be material.

There can be no assurance that we would be successful in attempting to mitigate the adverse impacts resulting from any changes in tax laws and regulations, including any changes in the interpretation of such tax authorities, or from audits and other matters. Our inability to mitigate the negative consequences of such actions could cause our global effective tax rate to increase, our use of cash to increase and our financial condition and results of operations to suffer.

The global effective tax rate that will apply subsequent to Brexit might become uncertain and may vary from expectations.

As further discussed below, on January 31, 2020, the U.K. withdrew as a member of the E.U., commonly referred to as Brexit, and the UK has since ratified a trade and cooperation agreement governing its future relationship with the E.U., which is being applied provisionally from January 1, 2021 until it is also ratified by the European Parliament and the Council of the E.U. The changes (which are ongoing) in applicable law and regulatory oversight of our operations caused by Brexit in the U.K. and the member states of the E.U. will impact how we conduct business in the U.K., within the E.U., and between the U.K. and the E.U., which may result in changes in the countries in which we derive a portion of our global earnings. As a result, our actual global effective tax rate may vary from expectations and that variance may be material as a result of Brexit.

Changes in our accounting estimates and assumptions could negatively affect our financial position and results of operations.

We prepare our consolidated financial statements in accordance with U.S. GAAP. These accounting principles require us to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of our consolidated financial statements. We are also required to make certain judgments that affect the reported amounts of revenues and expenses during each reporting period. We periodically evaluate our estimates and assumptions including, but not limited to, those relating to revenue recognition, pensions, recoverability of assets including customer receivables, valuation of goodwill and intangibles, contingencies, share-based payments, and income taxes. We base our estimates on historical experience and various assumptions that we believe to be reasonable based on specific circumstances. These assumptions and estimates involve the exercise of judgment and discretion, which may evolve over time in light of operational experience, regulatory direction, developments or changes in accounting principles or standards, and other factors. Actual results could differ from these estimates, or changes in assumptions, estimates, policies, or developments in the business may change our initial estimates, which could materially affect the Consolidated Statements of Income, Comprehensive Income, Financial Position, Shareholders’ Equity, and Cash Flows.

We may be required to record goodwill or other long-lived asset impairment charges, which could result in a significant charge to earnings.

Under U.S. GAAP, we review our long-lived assets for impairment when events or changes in circumstances indicate the carrying value may not be recoverable. Goodwill is assessed for impairment at least annually. Factors that may be considered in assessing whether goodwill or other long-lived assets may not be recoverable include a decline in our share price or market capitalization, reduced estimates of future cash flows and slower growth rates in our industry. We may experience unforeseen circumstances that adversely affect the value of our goodwill or other long- lived assets and trigger an evaluation of the recoverability of the recorded goodwill and other long-lived assets. Future goodwill or other long-lived asset impairment charges could materially impact our consolidated financial statements.

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

The Company is organized as a holding company, a legal entity separate and distinct from our operating entities. As a holding company without significant operations of its own, our principal assets are the shares of capital stock of our subsidiaries. We rely on dividends, interest, and other payments from these subsidiaries to meet our obligations for paying

16

principal and interest on outstanding debt, paying dividends to shareholders, repurchasing ordinary shares, and corporate expenses. Certain of our subsidiaries are subject to regulatory requirements of the jurisdictions in which they operate or other restrictions that may limit the amounts that subsidiaries can pay in dividends or other payments to us. No assurance can be given that there will not be further changes in law, regulatory actions, or other circumstances that could restrict the ability of our subsidiaries to pay dividends or otherwise make payments to us. Furthermore, no assurance can be given that our subsidiaries may be able to make timely payments to us in order for us to meet our obligations.

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.

We assist our clients with various matters, including advising on and placing insurance and reinsurance coverage and handling related claims, consulting on various human resources matters, and providing actuarial, investment consulting, and asset management services. E&O claims against us may allege our potential liability for damages arising from these services. E&O claims could include, for example, the failure of our employees or sub-agents, whether negligently or intentionally, to place coverage correctly or notify carriers of claims on behalf of clients, to provide insurance carriers with complete and accurate information relating to the risks being insured, or the failure to give error-free consulting or investment advice. It is not always possible to prevent and detect E&O, and the precautions we take may not be effective in all cases. In addition, we are subject to other types of claims, litigation, and proceedings in the ordinary course of business, which along with E&O claims, may seek damages, including punitive damages, in amounts that could, if awarded, have a material adverse impact on the Company’s financial position, earnings, and cash flows. In addition to potential liability for monetary damages, such claims or outcomes could harm our reputation or divert management resources away from operating our business.

We have historically purchased, and intend to continue to purchase, insurance to cover E&O claims and other insurance to provide protection against certain losses that arise in such matters. However, we have exhausted or materially depleted our coverage under some of the policies that protect us for certain years and, consequently, are self-insured or materially self-insured for some historical claims. Additionally, parts or all of an E&O claim could fall within insurance deductibles, self-insured retentions, or policy exclusions. Accruals for these exposures, and related insurance receivables, when applicable, have been provided to the extent that losses are deemed probable and are reasonably estimable. These accruals and receivables are adjusted from time to time as developments warrant and may also be adversely affected by disputes we may have with our insurers over coverage. Amounts related to settlement provisions are recorded in Other general expenses in the Consolidated Statements of Income. Discussion of some of these claims, lawsuits, and proceedings are contained in the Notes to Consolidated Financial Statements.

In addition, we provide a variety of guarantees and indemnifications to our customers and others. In the event of a default, our potential exposure is equal to the amount of the guarantee or indemnification.

The ultimate outcome of claims, lawsuits, proceedings, guarantees and indemnifications cannot be ascertained, and liabilities in indeterminate amounts may be imposed on us. It is possible that future results of operations or cash flows for any particular quarterly or annual period could be materially affected by an unfavorable resolution of these matters.

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

Our businesses are subject to extensive legal and regulatory oversight throughout the world, including the Irish Companies Act, the U.S. securities laws, rules, and regulations, the rules and regulations promulgated by the FCA and a variety of other laws, rules, and regulations addressing, among other things, licensing, data privacy and protection, trade sanctions laws, restrictions and export controls, anti-money laundering, wage-and-hour standards, employment and labor relations, anti-competition, anti-corruption, currency, reserves, government contracting, and the amount of local investment with respect to our operations in certain countries. This legal and regulatory oversight could reduce our profitability or limit our growth by: increasing the costs of legal and regulatory compliance; limiting or restricting the products or services we sell, the markets we serve or enter, the methods by which we sell our products and services, the overall structure of our business units, the type of services and prices we can charge for our services, or the form of compensation we can accept from our clients, carriers, and third parties; or by subjecting our businesses to the possibility of legal and regulatory actions, proceedings, or fines.

The global nature of our operations increases the complexity and cost of compliance with laws and regulations adding to our cost of doing business. In addition, many of these laws and regulations may have differing or conflicting legal standards across jurisdictions, increasing the complexity and cost of compliance. In emerging markets and other jurisdictions with less developed legal systems, local laws and regulations may not be established with sufficiently clear and reliable guidance to provide us adequate assurance that we are operating our business in a compliant manner with all required licenses or that our rights are otherwise protected. In addition, certain laws and regulations, such as the Foreign Corrupt Practices Act and the Foreign Account Tax Compliance provisions of the Hiring Incentives to Restore Employment Act in the U.S., and the Bribery Act of 2010 in the U.K., impact our operations outside of the legislating country by imposing requirements for the conduct of overseas operations, and in several cases, requiring compliance by foreign subsidiaries.

In addition to the complexity of the laws and regulations themselves, the development of new laws and regulations or changes in application or interpretation of current laws and regulations or conflict between them also increases our legal and regulatory compliance complexity. Additionally, our acquisitions of new businesses and our continued operational changes and entry into new jurisdictions and new service offerings increases our legal and regulatory compliance complexity, as well as the

17

type of governmental oversight to which we may be subject. Changes in laws and regulations could mandate significant and costly changes to the way we implement our services and solutions, impose additional licensure requirements or costs to our operations and services, or cause us to cease offering certain services or solutions. Furthermore, as we enter new jurisdictions or businesses and further develop and expand our services, including through acquisitions, we may become subject to additional types of laws and governmental oversight and supervision, such as those applicable to the financial lending or other service institutions. Regulatory developments that could result in changes that adversely affect us or cause us to change our business or operations include: additional requirements respecting data privacy, data security, and data usage in jurisdictions in which we operate that may increase our costs of compliance and potentially reduce the manner in which we can use data; changes in tax regulations in the jurisdictions in which we operate; regulatory actions or changes that require us to change our compensation model; or additional regulations promulgated by , regulatory bodies in jurisdictions in which we operate.

In all jurisdictions, the applicable laws and regulations are subject to amendment or interpretation by regulatory authorities. Generally, such authorities are vested with relatively broad discretion to grant, renew, and revoke licenses and approvals and to implement regulations. Accordingly, we may have a license revoked or be unable to obtain new licenses and therefore be precluded or suspended from carrying on or developing some or all of our activities or otherwise fined or penalized in a given jurisdiction. No assurances can be given that our business can further develop or continue to be conducted in any given jurisdiction in the future as it has been conducted in the past. Changes in the regulatory scheme, or even changes in how existing regulations are interpreted, could have an adverse impact on our results of operations by limiting revenue streams or increasing costs of compliance.

Our business’ regulatory oversight also includes licensing of insurance brokers and agents, managing general agency or general underwriting operations, and the regulation of the handling and investment of client funds held in a fiduciary capacity. Our continuing ability to provide insurance broking in the jurisdictions in which we operate depends on our compliance with the rules and regulations promulgated by the regulatory authorities in each of these jurisdictions. Also, we can be affected indirectly by the governmental regulation and supervision of insurance companies. For instance, if we are providing or managing general underwriting services for an insurer, we may have to contend with regulations affecting our client.

Services provided in our Health Solutions and Retirement Solutions service lines are also the subject of ever-evolving government regulation, either because the services provided to our clients are regulated directly or because third parties upon whom we rely to provide services to clients are regulated, thereby indirectly affecting the manner in which we provide services to those clients. In particular, our health care exchange business depends upon the private sector of the U.S. insurance system and its role in financing health care delivery, and insurance carriers’ use and payment of commissions to agents, brokers, and other organizations to market and sell individual and family health insurance products and plans. Uncertainty regarding, or any changes to, state or federal law, or the interpretation of such law by applicable regulatory agencies could delay client adoption of our health care exchanges, impair our ability to retain clients who have adopted our health care exchanges, or cause insurance carriers to alter or eliminate the products and plans that they offer or attempt to move members into new products or plans for which we receive lower commissions. In addition, changes in laws, government regulations, or the way those regulations are interpreted in the jurisdictions in which we operate could affect the viability, value, use, or delivery of benefits and human resources programs, including changes in regulations relating to health and welfare plans (such as medical), defined contribution plans (such as 401(k)), or defined benefit plans (such as pension), may adversely affect the demand for, or profitability of, our services.

If we violate the laws and regulations to which we are subject, we could be subject to fines, penalties, or criminal sanctions and could be prohibited from conducting business in one or more countries. There can be no assurance that our employees, contractors, or agents will not violate these laws and regulations, causing an adverse effect on our operations and financial condition.

Heightened regulatory oversight and scrutiny may lead to additional regulatory investigations, increased government involvement, or enforcement actions, which could consume significant management time and resources and could have adverse effects on our business and operations. For instance, increased scrutiny by competition authorities may increase our costs of doing business or force us to change the way we conduct business or refrain from or otherwise alter the way we engage in certain activities. Additionally, we could suffer significant financial or reputational harm if we fail to properly identify and manage potential conflicts of interest, which exist or could exist any time we or any of our employees have or may have an interest in a transaction or engagement that is inconsistent with our clients’ interests. This could occur, for example, when we are providing services to multiple parties in connection with a transaction. We also provide services to advise and assist in satisfying all our clients’ needs from all our businesses, creating a greater potential for conflicts with advisory services.

Due to the broad scope of our businesses and our client base, we regularly address potential conflicts of interest, including, without limitation, situations where our services to a particular client or our own investments or other interests conflict, or are perceived to conflict, with the interests of another client. If these are not adequately identified and managed, this could then lead to failure or perceived failure to protect the client’s interests, with consequential regulatory and reputational risks, including litigation or enforcement actions that could adversely affect us and our operations. Identifying conflicts of interest may also prove particularly difficult as we continue to bring systems and information together and integrate newly acquired businesses. In addition, we may not be able to adequately address such conflicts of interest.

Insurance intermediaries have traditionally been remunerated by base commissions paid by insurance carriers in respect of insurance placements for clients, or by fees paid by clients. Intermediaries also obtain other revenue from insurance carriers. This revenue, when derived from carriers in their capacity as insurance markets (as opposed to as corporate clients of the

18

intermediaries where they may be purchasing insurance or reinsurance or other non-market related services), is commonly known as market derived income (“MDI”). MDI is another example of an area in which potential conflicts of interest may arise. This revenue may be subject to scrutiny by various regulators under conflict of interest, anti-trust, unfair competition, conduct and anti-bribery laws and regulations. MDI takes a variety of forms, including volume- or profit-based contingent commissions, facilities administration charges, business development agreements, and fees for providing consulting services to carriers. While accepting MDI is a lawful and acceptable business practice, we cannot predict whether our position will result in regulatory or other scrutiny and our controls may not be fully effective.

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.

To protect our intellectual property rights, we rely on a combination of trademark laws, copyright laws, patent laws, trade secret protection, confidentiality agreements, and other contractual arrangements with our affiliates, employees, clients, strategic partners, and others, as well as internal policies and procedures regarding our management of intellectual property. However, the protective steps that we take may be inadequate to deter misappropriation of our proprietary information. In addition, we may be unable to detect the unauthorized use of, or take appropriate steps to enforce, our intellectual property rights. Further, we operate in many jurisdictions and effective trademark, copyright, patent, and trade secret protection may not be available or adequate in every country or jurisdiction in which we offer our services or employ our colleagues. Additionally, our competitors may develop products similar to our products that do not conflict with our related intellectual property rights. Failure to protect our intellectual property adequately could harm our reputation and affect our ability to compete effectively.

In addition, to protect or enforce our intellectual property rights, we may initiate litigation against third parties, such as infringement suits or interference proceedings. Third parties may assert intellectual property rights claims against us, which may be costly to defend, could require the payment of damages, and could limit our ability to use or offer certain technologies, products, or other intellectual property. Any intellectual property claims, with or without merit, could be expensive, take significant time and divert management’s attention from other business concerns. Successful challenges against us could require us to modify or discontinue our use of technology or business processes where such use is found to infringe or violate the rights of others, or require us to purchase licenses from third parties, any of which could adversely affect our business, financial condition, and operating results.

Operational Risks

Our results of operations have been adversely affected and could be materially adversely affected in the future by the COVID-19 global pandemic.

The COVID-19 global pandemic has created significant public health concerns and significant volatility, uncertainty, and economic disruption in every region where we operate.

A number of evolving factors related to the global pandemic and the post-pandemic recovery period may influence the duration, nature and extent of the impact on our business and financial results. Such factors include worldwide macroeconomic conditions, including interest rates, employment rates, consumer confidence and spending, gross domestic product, property values, and changes in client behavior, and foreign exchange rates in each of the markets in which we operate; business closures; changes in laws, regulations (including those changes that may provide for extended premium payment terms), and guidance; court decisions and litigation trends; a decline in business and the ability of counterparties to pay for our services on time or at all; an increased number of E&O claims in those areas impacted by the pandemic, as well as an increase in the incidence or severity of E&O claims against us and our market partners; our ability to sell and provide our services, including due to the impact of travel restrictions, lockdowns, quarantines, social distancing, and alternative work arrangements; the health of, and the effect of the pandemic on, our employees; political disruption; potential effects on our internal controls and risk mitigation processes, including those over financial reporting, as a result of changes in working environments for our employees and business partners; resurgences of spread; identification of new, more contagious variants of the virus; resulting “lockdowns,” government restrictions or recommendations; and uncertainties in vaccine manufacturing, accessibility and adoption.

In addition, the continuing COVID-19 pandemic may again create significant disruptions in the credit or financial markets, or impact our credit ratings, which could adversely affect our ability to access capital on favorable terms or at all.

Finally, the impact of the COVID-19 pandemic may heighten other risks discussed in this Annual Report on Form 10-K, which could adversely affect our business, financial condition, results of operations, cash flows, and stock price.

The economic and political conditions of the countries and regions in which we operate could have an adverse impact on our business, financial condition, operating results, liquidity, and prospects for growth.

Our operations in countries undergoing political change or experiencing economic instability are subject to uncertainty and risks that could materially adversely affect our business. These risks include, particularly in emerging markets, the possibility we would be subject to undeveloped or evolving legal systems, unstable governments and economies, and potential governmental actions affecting the flow of goods, services, and currency.

Furthermore, the U.K. formally withdrew from the E.U., commonly referred to as Brexit, and ratified a trade cooperation agreement governing its future relationship with the E.U. The agreement, which is being applied provisionally from January 1, 2021 until it is ratified by the European Parliament and the Council of the E.U., addresses trade, economic arrangements, law

19

enforcement, judicial cooperation and a governance framework including procedures for dispute resolution, among other things. Because the agreement merely sets forth a framework in many respects and will require complex additional bilateral negotiations between the U.K. and the E.U. as both parties continue to work on the rules for implementation, significant political and economic uncertainty remains. We have significant operations and a substantial workforce within the country, and we enjoy certain benefits based on the U.K.’s membership in the E.U., and the lack of clarity around the future relationship between the U.K. and the E.U. creates uncertainty that may have a material impact on our business and operations. We may also be required to incur additional expense as we adapt to and create the ability to operate within the new political and regulatory environment.

Additionally, any development that has the effect of devaluing the euro or British pound could meaningfully reduce the value of our assets and reduce the usefulness of liquidity alternatives denominated in that currency such as our multicurrency U.S. credit facility. We also deposit some of our cash, including cash held in a fiduciary capacity, with certain European financial institutions. While we continuously monitor and manage exposures associated with those deposits, to the extent the uncertainty surrounding economic stability in Europe and the future viability of the euro suddenly and adversely impacts those financial institutions, some or all of those cash deposits could be at risk.

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

We depend, in material part, upon the members of our senior management team who possess extensive knowledge and a deep understanding of our business and our strategy, as well as the colleagues who are critical to developing and retaining client relationships. The unexpected loss of services of any of these senior leaders could have a disruptive effect adversely impacting our ability to manage our business effectively and execute our business strategy. Competition for experienced professional personnel is intense, and we are constantly working to retain, attract and develop these professionals. If we cannot successfully do so, our business, operating results, and financial condition could be adversely affected. While we have plans for key management succession and long-term compensation plans designed to retain our senior management team and critical colleagues, if our succession plans and retention programs do not operate effectively, our business could be adversely affected. We also are committed to diversity and inclusion and strive to maintain an equitable work environment that unlocks the full potential of all of our personnel. If we are unsuccessful in maintaining such a work environment, we could experience difficulty attracting and retaining personnel, which could have a negative impact on our business.

Our global operations expose us to various international risks that could adversely affect our business.

Our operations are conducted globally. Accordingly, we are subject to regulatory, legal, economic, and market risks associated with operating in, and sourcing from, foreign countries, including:

•difficulties in staffing and managing our foreign offices, including due to unexpected wage inflation or job turnover, and the increased travel, infrastructure, and legal and compliance costs and risks associated with multiple international locations;

•hyperinflation in certain foreign countries;

•conflicting regulations in the countries in which we do business;

•imposition of investment requirements or other restrictions by foreign governments;

•longer payment cycles;

•greater difficulties in collecting accounts receivable;

•insufficient demand for our services in foreign jurisdictions;

•our ability to execute effective and efficient cross-border sourcing of services on behalf of our clients;

•the reliance on or use of third parties to perform services on behalf of the Company;

•disparate tax regimes;

•restrictions on the import and export of technologies; and

•trade barriers.

The occurrence of natural or man-made disasters could result in declines in business and increases in claims that could adversely affect our financial condition and results of operations.

We are exposed to various risks arising out of natural disasters, including earthquakes, hurricanes, fires, floods, tornadoes, extreme weather, or other climate events; pandemic health events, and man-made disasters, including acts of terrorism, civil unrest, violence, military actions, and cyber-terrorism. The continued threat of terrorism and other events or disasters may cause significant volatility in global financial markets, and a natural or man-made disaster could trigger energy shortages, public health issues, or an economic downturn or instability in the areas directly or indirectly affected by the disaster. These

20

consequences could, among other things, result in a decline in business and increased claims from those areas. They could also result in reduced underwriting capacity, making it more difficult for our professionals to place business. Disasters also could disrupt public and private infrastructure, including communications and financial services, which could disrupt our normal business operations.

A natural or man-made disaster also could disrupt the operations of our counterparties or result in increased prices for the products and services they provide to us. In addition, a disaster could adversely affect the value of the assets in our investment portfolio. Finally, a natural or man-made disaster could increase the incidence or severity of E&O claims against us.

Our inability to successfully recover should we experience a disaster or other business continuity problem could cause material financial loss, loss of human capital, regulatory actions, reputational harm, or legal liability.

Our operations are dependent upon our ability to protect our personnel, offices, and technology infrastructure against damage from business continuity events that could have a significant disruptive effect on our operations. Should we experience a local or regional disaster or other business continuity problem, such as a security incident or attack, a natural disaster, climate event, terrorist attack, pandemic, power loss, telecommunications failure, or other natural or man-made disaster, our continued success will depend, in part, on the availability of our personnel and office facilities, and the proper functioning of computer systems, telecommunications, and other related systems and operations. In events like these, while our operational size, the multiple locations from which we operate, and our existing back-up systems provide us with some degree of flexibility, we still can experience near-term operational challenges in particular areas of our operations. We could potentially lose access to key executives, personnel, or client data or experience material adverse interruptions to our operations or delivery of services to our clients in a disaster recovery scenario. A disaster on a significant scale or affecting certain of our key operating areas within or across regions, or our inability to successfully recover should we experience a disaster or other business continuity problem, could materially interrupt our business operations and cause material financial loss, loss of human capital, regulatory actions, reputational harm, damaged client relationships, or legal liability.

We rely on third parties to perform key functions of our business operations enabling our provision of services to our clients. These third parties may act in ways that could harm our business.

We rely on third parties, and in some cases subcontractors, to provide services, data, and information such as technology, information security, funds transfers, data processing, support functions, and administration that are critical to the operations of our business. These third parties include correspondents, agents and other brokerage and intermediaries, insurance markets, data providers, plan trustees, payroll service providers, benefits administrators, software and system vendors, health plan providers, investment managers, and providers of human resources, among others. As we do not fully control the actions of these third parties, we are subject to the risk that their decisions, actions, or inactions may adversely impact us and replacing these service providers could create significant delay and expense. A failure by third parties to comply with service level agreements or regulatory or legal requirements in a high quality and timely manner, particularly during periods of our peak demand for their services, could result in economic and reputational harm to us. In addition, we face risks as we transition from in-house functions to third- party support functions and providers that there may be disruptions in service or other unintended results that may adversely affect our business operations. These third parties face their own technology, operating, business, and economic risks, and any significant failures by them, including the improper use or disclosure of our confidential client, employee, or company information, could cause harm to our business and reputation. An interruption in or the cessation of service by any service provider as a result of systems failures, cybersecurity incidents, capacity constraints, financial difficulties, or for any other reason could disrupt our operations, impact our ability to offer certain products and services, and result in contractual or regulatory penalties, liability claims from clients, or employees, damage to our reputation, and harm to our business.

Our business is exposed to risks associated with the handling of client funds.

Certain of our businesses collect premiums from insureds and remits the premiums to the respective insurers. We also collect claims or refunds from insurers on behalf of insureds, which are then remitted to the insureds. Consequently, at any given time, we may be holding and managing funds of our clients. This function creates a risk of loss arising from, among other things, fraud by employees or third parties, execution of unauthorized transactions, errors relating to transaction processing, or other cybersecurity events or security breaches. We are also potentially at risk in the event the financial institution in which we hold these funds suffers any kind of insolvency or liquidity event. The occurrence of any of these types of events in connection with this function could cause us financial loss and reputational harm.

In connection with the implementation of our corporate strategies and initiatives, we face risks associated with, among others, the acquisition or disposition of businesses, the integration and development of acquired businesses, and the entry into new lines of business or products.

In pursuing our corporate strategy, we often acquire other businesses or dispose of or exit businesses we currently own and we routinely are actively engaged in the process of identifying, analyzing, and negotiating possible transactions. The success of this strategy is dependent upon our ability to identify appropriate acquisition and disposition targets, negotiate transactions on favorable terms, complete transactions and, in the case of acquisitions, successfully integrate them into our existing businesses and culture. If a proposed transaction is not consummated, the time and resources spent pursuing it could adversely result in missed opportunities to locate and acquire other businesses. If acquisitions are made, there can be no assurance that we will realize the anticipated benefits of such acquisitions, including, but not limited to, revenue growth, operational efficiencies, or expected synergies, and we could incur unexpected costs in connection with integration. If we dispose of or otherwise exit

21

certain businesses, there can be no assurance that we will not incur certain disposition related charges, we will be able to reduce overhead related to the divested assets, or will realized the intended benefits of the disposition.

We may enter new lines of business or offer new products and services within existing lines of business either through acquisitions or through initiatives to generate organic revenue growth. These new lines of business, products, and services present the Company with additional risks, particularly in instances where the markets are new or not fully developed. Such risks include the investment of significant time and resources; the possibility that these efforts will be not be successful; the possibility that the marketplace does not accept our products or services or that we are unable to retain clients that adopt our new products or services; and the risk of new or additional liabilities associated with these efforts. In addition, many of the businesses that we acquire and develop will likely have significantly smaller scales of operations prior to the implementation of our growth strategy. If we are not able to manage the growing complexity of these businesses, including improving, refining, or revising our systems and operational practices, and enlarging the scale and scope of the businesses, our business may be adversely affected. Other risks include developing knowledge of and experience in the new business, product or service, integrating the acquired business into our systems and culture, recruiting and retaining experienced professionals, and developing and capitalizing on new relationships with experienced market participants. External factors, such as compliance with new or revised regulations, competitive alternatives, and shifting market preferences may also impact the successful implementation of a new line of business, products, or services. Failure to manage these risks in the acquisition or development of new businesses could materially and adversely affect our business, results of operations, and financial condition.

We are subject to various risks and uncertainties in connection with the sale of the Divested Business.

On May 1, 2017, the Company completed the sale of the benefits administration and business process outsourcing business (the “Divested Business) to an entity controlled by affiliates of The Blackstone Group L.P. (the “Buyer”). This transaction carries inherent risks, including the risk that we will not earn the $500 million of additional consideration or otherwise realize the intended value of the transaction.

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.

We rely on the efficient, uninterrupted, and secure operation of complex information technology systems and networks, some of which are within the Company and some of which are outsourced to third parties. All information technology systems are potentially vulnerable to damage or interruption from a variety of sources, including but not limited to cyber-attacks, computer viruses, security breaches, and unauthorized access or improper actions by insiders or employees. We are at risk of attack by a growing list of adversaries through new and increasingly sophisticated methods of attack, including methods that take advantage of remote work scenarios due to COVID-19. Because the techniques used to obtain unauthorized access or sabotage systems change frequently, we may be unable to anticipate these techniques, implement adequate preventative measures, or detect and respond quickly enough in the event of an incident or attack. We regularly experience social engineering attempts, attacks to our systems and networks and have from time to time experienced cybersecurity incidents, such as computer viruses, unauthorized parties gaining access to our information technology systems, data loss via malicious and non-malicious methods, and similar incidents, which to date have not had a material impact on our business. If we are unable to efficiently and effectively maintain and upgrade our system safeguards, we may incur unexpected costs and certain of our systems may become more vulnerable to unauthorized access. Problems with the information technology systems of vendors, including breakdowns or other disruptions in communication services provided by a vendor, failure of a vendor to handle current or higher volumes, difficulties in the migration of services or data to third parties or the cloud hosted by third parties, cyber-attacks, and security breaches could adversely affect our ability to deliver products and services to customers and otherwise conduct business. Additionally, we are a global and acquisitive organization and we therefore might not adequately identify weaknesses in certain of our information systems, including those of targets we acquire, which could expose us to unexpected liabilities and fines or make our own systems more vulnerable to attack. These types of incidents affecting us or our third-party vendors could result in intellectual property or other confidential information being lost or stolen, including client or employee personal information or company data.

We have implemented various measures to manage our risks related to system and network security and disruptions, but a security breach or a significant or extended disruption in the functioning of our information technology systems could damage our reputation, cause us to lose clients, adversely impact our operations, sales, and operating results, and require us to incur significant expense and divert resources to address and remediate or otherwise resolve such issues. Additionally, in order to maintain the level of security, service, and reliability that our clients require, we may be required to make significant additional investments in our information technology system.

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

One of our significant responsibilities is to maintain the security and privacy of our employees’ and clients’ confidential and proprietary information, including confidential information about our clients’ and employees’ compensation, medical information, and other personally identifiable information. We maintain policies, procedures, and technological safeguards designed to protect the security and privacy of this information. Nonetheless, we cannot eliminate the risk of human error,

22

employee or vendor malfeasance, or cyber-attacks that could result in improper access to or disclosure of confidential, personal, or proprietary information. Such access or disclosure could harm our reputation and subject us to liability under our contracts and laws and regulations that protect personal data, resulting in increased costs, fines, loss of revenue, and loss of clients. The release of confidential information as a result of a security breach could also lead to litigation or other proceedings against us by affected individuals or business partners, or by regulators, and the outcome of such proceedings, which could include penalties or fines, could have a significant negative impact on our business.

In many jurisdictions, including in the E.U. and the U.S., we are subject to laws and regulations relating to the collection, use, retention, security, and transfer of this information. These laws and regulations are frequently changing and are becoming increasingly complex and sometimes conflict among the various jurisdictions and countries in which we provide services both in terms of substance and in terms of enforceability. This makes compliance challenging and expensive. Additionally, certain jurisdictions’ regulations include notice provisions that may require us to inform affected clients or employees in the event of a breach of confidential information before we fully understand or appreciate the extent of the breach. These notice provisions present operational challenges and related risk. In particular, in 2020 there have been a number of new privacy laws around the globe including Brazil, California, South Africa and Dubai. We have had to implement new requirements set out in these laws within our business before the effective date causing distraction from other aspects of our business. Additionally the US Privacy Shield was invalidated by the EU causing significant uncertainty for business transferring personal data from the EU to the US. New guidance issued to firms will require time to implement and may require significant effort to review and effect applicable changes to IT systems and transfer methods. Non-compliance with new and existing laws could result in proceedings against us by governmental entities or others and additional costs in connection therewith. We expect additional jurisdictions to continue to adopt new privacy regulations and there to be amendments to existing regulations as governments continue to legislate in respect of personal data. We have and will continue to incur expenses and devote resources to bring our practices into compliance with these regulations and future regulations. Our failure to comply with or successfully implement processes in response to changing regulatory requirements in this area could result in legal liability, result in proceedings or fines against us by governmental entities or others, or impair our reputation in the marketplace. Further, regulatory initiatives in the area of data protection are more frequently including provisions allowing authorities to impose substantial fines and penalties, and therefore, failure to comply could also have a significant financial impact.

Our business performance and growth plans could be negatively affected if we are not able to develop and implement technology-based solutions to support our business operations or if we are not able to effectively drive value for our clients through innovation and technology-based solutions.

Our success depends, in part, on our ability to enhance and implement the technology systems necessary to operate our businesses and to achieve intended efficiencies and improvements. We may not be successful in anticipating or responding to rapid and continuing changes in technology, industry standards and client preferences. The effort to gain technological expertise, develop new technologies in our business, and achieve internal efficiencies through technology require us to incur significant expenses.

We also make investments in technology-based solutions, including data and analytics solutions, for our clients. If we cannot innovate as quickly as our competitors, if our competitors develop more cost-effective technologies, or if our ideas are not accepted in the marketplace, it could have a material adverse effect on our ability to obtain and complete client engagements. For example, we have invested significantly in the development of our proprietary data and analytics tools including repositories of global insurance and reinsurance placement information, which we use to drive results for our clients in the insurance and reinsurance placement process. Our competitors are developing competing data and analytics tools, and their success in this space may impact our ability to differentiate our services to our clients through the use of unique technological solutions. Innovations in software, cloud computing, data and analytics or other technologies that alter how our services are delivered could significantly undermine our investment in the business if we are slow to innovate or unable to take advantage of these developments.

Risks Related to the Combination

The Combination is subject to customary closing conditions, including conditions related to regulatory approvals, and may not be completed on a timely basis, or at all, or may be completed on a basis that has a material impact on the value of the combined company.

The closing of the pending combination of the Combination is subject to a number of customary conditions, and there can be no assurance that the conditions to the closing of the Combination will be satisfied or waived (to the extent applicable). The failure to satisfy the required conditions could delay the closing of the Combination for a significant period of time or prevent the closing of the Combination from occurring at all. These closing conditions include, among others, the approval of the scheme by the Irish High Court and certain antitrust related clearances, including under the Hart–Scott–Rodino Antitrust Improvements Act (the “HSR Act”), the European Commission Merger Regulation and the antitrust laws of the other required antitrust jurisdictions.

The governmental agencies from which the parties will seek certain approvals related to these conditions have broad discretion in administering the applicable governing regulations. As a condition to their approval of the Combination, agencies may impose requirements, limitations or costs or require divestitures or place restrictions on the conduct of the combined company’s business after the closing of the Combination. Such requirements, limitations, costs or restrictions could delay or

23

prevent the closing of the Combination or have a material adverse effect on the combined company’s business and results of operations following the closing of the Combination.

In addition, the closing conditions include other legal and regulatory conditions, such as (i) the sanction by the Irish High Court of the scheme and the delivery of the court order to the Irish Registrar of Companies, (ii) the approval by the NYSE of the listing of all of our Class A ordinary shares to be issued in connection with the scheme and (iii) the absence of any law or order that restrains, enjoins, makes illegal or otherwise prohibits the closing of the Combination.

The Combination is also subject to other customary closing conditions, including: (i) the Business Combination Agreement not having been terminated in accordance with its terms; (ii) the accuracy of each party’s representations and warranties made in the Business Combination Agreement, subject to specified materiality standards; (iii) the absence of a material adverse effect with respect to each party since March 9, 2020; and (iv) the performance and compliance by each party of all of its obligations and compliance with all of its covenants under the Business Combination Agreement in all material respects. There can be no assurance that the conditions to the closing of the Combination will be satisfied or waived or that the Combination will be completed within the expected time frame, or at all.

In addition, if the Combination is not completed by March 9, 2021 (or June 9, 2021 or September 9, 2021, if extended under the terms of the Business Combination Agreement, if applicable, or such earlier date as may be specified by the Irish Takeover Panel), either we or WTW may choose not to proceed with the Combination. The parties can mutually decide to terminate the Business Combination Agreement at any time.

Failure to close the Combination could negatively impact our share price and future business and financial results.

If the Combination is not completed for any reason, our ongoing business may be adversely affected and, without realizing any of the potential benefits of having closed the Combination, we will be subject to a number of risks, including the following:

•we will be required to pay certain costs and expenses relating to the Combination;

•if the Business Combination Agreement is terminated under specified circumstances, we may be obligated to reimburse certain Combination expenses of WTW or, if terminated under other circumstances related to a failure to obtain the required antitrust clearances, pay to WTW a termination fee equal to $1 billion;

•we may experience negative reactions from the financial markets, including negative impacts on the market price of our securities;

•the manner in which clients, vendors, business partners and other third parties perceive us may be negatively impacted, which in turn could affect our ability to compete for new business or to obtain renewals in the marketplace;

•matters relating to the Combination (including integration planning) may require substantial commitments of time and resources by management, which could otherwise have been devoted to other opportunities that may have been beneficial to us;

•the Business Combination Agreement restricts us, without WTW’s consent and subject to certain exceptions, from making certain acquisitions and taking other specified actions until the Combination occurs or the Business Combination Agreement terminates. These restrictions may prevent us from pursuing otherwise attractive business opportunities and making other business changes to our business that may arise prior to the closing of the Combination or the termination of the Business Combination Agreement; and

•we could be subject to litigation related to any failure to close the Combination or related to any enforcement proceeding commenced against us to perform our obligations under the Business Combination Agreement.

If the Combination does not close, these risks may materialize and may adversely affect our business, financial results and share price.

While the Combination is pending, we are subject to business uncertainties related to our relationships with employees, clients and suppliers, which could adversely affect our business and operations. These uncertainties could also adversely affect the combined company following the Combination.

Uncertainty about the effect of the Combination on employees, clients and suppliers may have an adverse effect on us and, consequently, on the combined company. These uncertainties may impair our ability to attract, retain and motivate key personnel until the closing of the Combination and for a period of time thereafter, and could cause clients, suppliers and others who deal with us to seek to delay or defer business decisions, to change or terminate existing business relationships with us, or for potential clients to choose other partners instead of us or to take other actions as a result of the Combination that could negatively impact the combined company’s and/or our revenues, earnings, cash flows and the market price of our securities. Employee retention may be particularly challenging during the pendency of the Combination because employees may experience uncertainty about their future roles with the combined company. If, despite our retention efforts, key employees

24

depart because of issues relating to the uncertainty and difficulty of integration or a desire not to remain with the combined company, the combined company’s business could be harmed and its ability to realize the anticipated benefits of the Combination could be adversely affected. Further, uncertainty around the timing of the closing may heighten risk of employee attrition

If completed, the Combination may not achieve its intended results.

We entered into the Business Combination Agreement with the expectation that the Combination would result in various benefits, including, among other things, synergies at the combined company, a comprehensive and more innovative product portfolio, diversified growth profile and broad geographic reach. Achieving the anticipated benefits of the Combination is subject to a number of uncertainties, including whether our and WTW’s businesses can be integrated in an efficient and effective manner. Failure to achieve, a delay in achieving, or an increase in the costs to achieve, these anticipated benefits, in whole or in part, could result in increased costs or decreases in expected revenues and could adversely affect the combined company’s future business, financial condition, operating results and cash flows. Additionally, if any governmental agencies, in connection with the Combination, require divestitures or place restrictions on the conduct of the combined company’s business after the closing of the Combination, such requirements or restrictions could reduce the anticipated benefits of the Combination.

We and WTW may be unable to successfully integrate their operations. Failure to successfully integrate our and WTW’s businesses in the expected timeframe may adversely affect the future results of the combined company.

Our and WTW’s ability to realize the anticipated benefits of the Combination will depend, to a large extent, on the ability to integrate our and WTW’s business. The combination of two independent businesses is a complex, costly and time-consuming process. As a result, significant management attention and resources will be devoted to integrating our and WTW’s business practices and operations. The integration process may disrupt the businesses and, if implemented ineffectively, would preclude realization of the full expected benefits. A failure to meet the challenges involved in integrating the two businesses and to realize the anticipated benefits of the Combination could adversely affect the combined company’s results of operations.

In addition, the overall integration of the businesses may result in material unanticipated problems, expenses, liabilities, competitive responses, loss of client relationships and diversion of management’s attention. The difficulties of combining the operations of the companies include, among others: the diversion of management attention to integration matters; difficulties in achieving anticipated cost savings, synergies, business opportunities and growth prospects from combining the businesses; difficulties in the integration of operations and systems; unanticipated costs, delays and other hardships to integration efforts, including any such costs, delays or hardships, caused by pandemic, epidemic or outbreak of an infectious disease, including COVID-19 and the resulting travel and operations restrictions; difficulties in the assimilation of employees and culture; difficulties in managing the expanded operations of a larger and more complex company; challenges in retaining existing clients and obtaining new clients; and challenges in attracting and retaining key personnel.

Many of these factors will be outside of our control and any one of them could result in increased costs, decreases in expected revenues and diversion of management’s time and attention, which could materially impact the business, financial condition and results of operations of the combined company. In addition, even if the operations of our and WTW’s businesses are integrated successfully, the full benefits of the Combination, including the synergies, cost savings or sales or growth opportunities that are expected, may not be realized within the anticipated time frame or at all. Further, additional unanticipated costs may be incurred in the integration of our and WTW’s businesses. All of these factors could decrease or delay the expected accretive effect of the Combination and negatively impact the combined company’s results of operations.

We have incurred and will incur substantial Combination fees and costs in connection with the Combination.

We have incurred and expect to incur a number of non-recurring substantial Combination-related costs associated with the closing of the Combination, combining the operations of the two organizations and achieving desired synergies. These fees and costs will be substantial, and a portion of them will be incurred regardless of whether the Combination closes. Non-recurring Combination costs include, but are not limited to, fees paid to legal, financial and accounting advisors, retention, severance, change in control and other integration-related costs, filing fees and printing costs.

Additional unanticipated costs may be incurred in connection with the closing and the integration of our and WTW’s businesses. There can be no assurance that the elimination of certain duplicative costs, as well as the realization of other efficiencies related to the integration of the two businesses, will offset the incremental Combination-related costs over time. Thus, any net benefit may not be achieved in the near term, the long term or at all, and these costs could adversely affect our financial conditions and results of operation prior to the closing and of the combined company following the closing.

The global effective tax rate that will apply to the combined group subsequent to the Combination is uncertain and may vary from expectations.

There can be no assurance that closing of the Combination pursuant to the Business Combination Agreement, will allow the combined group to maintain any particular global effective corporate tax rate. No assurances can be given as to what the

25

combined group’s global effective tax rate will be after the closing of the Combination because of, among other things, uncertainty regarding the jurisdictions in which the combined group will derive income and the amounts derived thereof, uncertainty regarding the ability and the time necessary to integrate business operations and entities, and uncertainty regarding the tax policies of the jurisdictions in which it will operate. As a result, the combined group’s actual global effective tax rate may vary from expectations following the Combination and that variance may be material.

Litigation filed against WTW and/or Aon could prevent or delay the completion of the transaction or result in the payment of damages following completion of the transaction.

WTW, Aon and members of the WTW Board may in the future be parties, among others, to various claims and litigation related to the Business Combination Agreement and the transaction. The results of complex legal proceedings are difficult to predict, and could delay or prevent the transaction from being completed in a timely manner, and could result in substantial costs to Aon and WTW, including, but not limited to, costs associated with the indemnification of their respective directors and officers.

One of the conditions to the closing of the transaction is that no order (whether temporary or permanent) has been issued, promulgated, made, rendered or entered into by any court or other tribunal of competent jurisdiction which restrains, enjoins, makes illegal or otherwise prohibits the consummation of the transaction (excluding certain laws and orders unrelated to the required antitrust clearances and the required regulatory clearances). Consequently, if plaintiffs are successful in obtaining an injunction prohibiting WTW and Aon from completing the transaction on the terms contemplated by the Business Combination Agreement, such an injunction may delay the completion of the transaction in the expected timeframe, or may prevent the transaction from being completed altogether.

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.

It may not be possible to enforce court judgments obtained in the U.S. against us in Ireland, based on the civil liability provisions of the U.S. federal or state securities laws. In addition, there is some uncertainty as to whether the courts of Ireland would recognize or enforce judgments of U.S. courts obtained against us or our directors or officers based on the civil liabilities provisions of the U.S. federal or state securities laws or hear actions against us or those persons based on those laws. We have been advised that the U.S. currently does not have a treaty with Ireland providing for the reciprocal recognition and enforcement of judgments in civil and commercial matters. Therefore, a final judgment for the payment of money rendered by any U.S. federal or state court based on civil liability, whether or not based solely on U.S. federal or state securities laws, would not automatically be enforceable in Ireland.

As an Irish company, we are governed by the Irish Companies Act, which differs in some material respects from laws generally applicable to U.S. corporations and shareholders, including, among others, differences relating to interested director and officer transactions and shareholder lawsuits. Likewise, the duties of directors and officers of an Irish company generally are owed to the company only. Shareholders of Irish companies generally do not have a personal right of action against directors or officers of the company and may exercise such rights of action on behalf of the company only in limited circumstances. Accordingly, holders of our securities may have more difficulty protecting their interests than would holders of securities of a corporation incorporated in a jurisdiction of the U.S.

In addition, depending on the circumstances, the acquisition, ownership and/or disposition of our ordinary shares may subject shareholders to different or additional tax consequences under Irish law including, but not limited to, Irish stamp duty, dividend withholding tax and capital acquisitions tax.

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 generally provides that a board of directors may allot and issue shares (or rights to subscribe for or convert into shares) if authorized to do so by a company’s constitution or by an ordinary resolution of shareholders. Such authorization may be granted in respect of up to the entirety of a company’s authorized but unissued share capital and for a maximum period of five years, at which point it must be renewed by another ordinary resolution. The Company’s constitution authorizes our directors to allot shares up to the maximum of the Company’s authorized but unissued share capital for a period of five years from March 31, 2020. This authorization will need to be renewed by ordinary resolution upon its expiration and at periodic intervals thereafter. Under Irish law, an allotment authority may be given for up to five years at each renewal, but governance considerations may result in renewals for shorter periods or in respect of less than the maximum permitted number of shares being sought or approved.

Irish law also generally provides shareholders with statutory pre-emption rights when new shares are issued for cash. However, it is possible for such statutory pre-emption rights to be dis-applied in a company’s constitution or by a special resolution of shareholders. Such dis-application of pre-emption rights may be given in respect of up to the entirety of a

26

company’s authorized but unissued share capital and for a maximum period of five years, at which point it must be renewed by another special resolution. The Company’s constitution dis-applies statutory pre-emption rights up to the maximum of the Company’s authorized but unissued share capital for a period of five years from March 31, 2020. This dis-application will need to be renewed by special resolution upon its expiration and at periodic intervals thereafter. Under Irish law, a dis-application of statutory pre-emption rights may be given for up to five years at each renewal, but governance considerations may result in renewals for shorter periods or in respect of less than the maximum permitted number of unissued shares being sought or approved.

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

Under Irish law, we may only pay dividends and, generally, make share repurchases and redemptions from distributable profits. Distributable profits may be created through the earnings of the Company or other methods (including certain intra-group reorganizations involving the capitalization of the Company’s un-distributable profits and their subsequent reduction). While it is our intention to maintain a sufficient level of distributable profits in order to pay dividends on our ordinary shares and make share repurchases, there is no assurance that the Company will maintain the necessary level of distributable profits to do so.

Item 1B.    Unresolved Staff Comments

None.

Item 2.    Properties

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 Metropolitan Building, James Joyce Street, Dublin 1, Ireland, where we occupy approximately 43,000 square feet of space under an operating lease agreement that expires in 2032. The following are additional significant leased properties, along with the occupied square footage and expiration.

Property:	Occupied Square Footage	Lease Expiration Dates
200 E. Randolph Street, Chicago, Illinois	391,000	2028
4 Overlook Point, Lincolnshire, Illinois	242,000	2024
165 Broadway, New York, New York	237,000	2028
122 Leadenhall Street, London, England	195,000	2034

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. Due to COVID-19, the vast majority of colleagues are working remotely. We will reoccupy our remaining offices as local mandates are lifted and once protocols are in place to ensure a safe work environment. 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, 2020.

Item 3.    Legal Proceedings

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.

Item 4.    Mine Safety Disclosure

Not applicable.

27

Information about our Executive Officers

The executive officers of Aon, as of February 19, 2021 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.

Name	Age	Position
Eric Andersen	56	President. Mr. Andersen joined Aon in 1997 upon the completion of the acquisition of Minet. Mr. Andersen has served in a variety of roles during his more than 20 year career at Aon, including as Chief Executive Officer of Aon Risk Solutions Americas from 2011 to 2013, and Chief Executive Officer of Aon Benfield from September 2013 to May 2018. He was named an Executive Officer in February 2017.
Gregory C. Case	58	Chief Executive Officer. Mr. Case became Chief Executive Officer of Aon in April 2005. He also served as Aon’s President from April 2005 to May 2018. Prior to joining Aon, Mr. Case was a partner with McKinsey & Company, a global management consulting firm, for 17 years, most recently serving as head of the Financial Services Practice. He previously was responsible for McKinsey’s Global Insurance Practice and was a member of McKinsey’s governing Shareholders’ Committee. Prior to joining McKinsey, Mr. Case worked for the investment banking firm of Piper, Jaffray and Hopwood and the Federal Reserve Bank of Kansas City.
Christa Davies	49	Chief Financial Officer. Ms. Davies became Executive Vice President - Global Finance in November 2007. In March 2008, Ms. Davies assumed the additional role of Chief Financial Officer. Prior to joining Aon, Ms. Davies served for 5 years in various capacities at Microsoft Corporation, an international software company, most recently serving as Chief Financial Officer of the Platform and Services Division. Before joining Microsoft in 2002, Ms. Davies served at ninemsn, an Australian joint venture with Microsoft.
Anthony Goland	61	Chief Innovation Officer. Mr. Goland joined Aon in September 2015 as Chief Human Resources Officer and served in that position through October 2018. Prior to joining Aon, Mr. Goland spent 30 years at McKinsey & Company, where he was a leader of the firm’s financial services, financial inclusion, and organization practices. Prior to McKinsey, he had experience with J.P. Morgan and IBM, and before that he volunteered and served as a Sergeant in the U.S. Army.
Michael Neller	42	Chief Accounting Officer and Global Controller. Mr. Neller joined Aon in August 2011 as its Vice President, Technical Accounting and Policy. From December 2011 to February 2018, Mr. Neller served as Aon’s Deputy Global Controller. In this role, he was responsible for Aon’s Latin America and North America regions, as well as global accounting policy, corporate accounting, and external reporting. Before joining Aon, Mr. Neller served from July 2009 to August 2011 as a Senior Manager of KPMG LLP, an international public accounting firm, in its Department of Professional Practice (National Office). He was named Senior Vice President and Global Controller in February 2018.
Lisa Stevens	50	Chief People Officer. Ms. Stevens joined Aon in December 2018 as Global Executive Vice President and was named as Chief People Officer in October 2019. Prior to joining Aon, Ms. Stevens held a variety of roles during her 29-year career at Wells Fargo, most recently as Executive Vice President where she led the Western Region for the Community Bank.
Andy Weitz	44	Global Chief Marketing Officer. Mr. Weitz joined Aon in 2014 as Senior Vice President for Global Marketing and Communications. Before joining Aon, Mr. Weitz was President and CEO of the U.S. region for Hill + Knowlton Strategies, a global strategic communications consultancy. Prior to Hill + Knowlton, Mr. Weitz worked at Marsh, Inc., a global insurance brokerage, and served in various roles at Trilogy, Inc. a software company.
Darren Zeidel	49	General Counsel and Company Secretary. Mr. Zeidel was named General Counsel and Company Secretary in July 2019. Prior to this Mr. Zeidel held several leadership roles with Aon, including as Deputy General Counsel immediately prior to his appointment; Global Chief Counsel - Corporate, Retirement & Investment and Health Exchanges from 2017 to 2019; and Global Chief Counsel of Aon Hewitt upon joining Aon in 2012 to 2017. Before this Mr. Zeidel worked for Honeywell, where he held business segment general counsel roles in the aerospace strategic business unit and at Honeywell UOP LLC. Mr. Zeidel began his career as an Associate in the Mergers and Acquisitions group in the New York office of Skadden, Arps, Slate, Meagher & Flom, LLP.

28

PART II

Item 5.    Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

Our Class A Ordinary Shares, $0.01 nominal value per share, are traded on the NYSE under the trading symbol AON.

On February 18, 2021, the last reported sale price of our ordinary shares as reported by the NYSE was $227.26 per share. We have approximately 375 holders of record of our Class A Ordinary Shares as of February 18, 2021.

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

Period	Total Number of Shares Purchased	Average Price Paid per Share (1)		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs (2)	Maximum Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs (1) (2)
10/1/20 – 10/31/20	704,343	$	205.51	704,343	$	918,034,066
11/1/20 – 11/30/20	1,047,119	$	199.55	1,047,119	$	5,709,085,686
12/1/20 – 12/31/20	2,142,958	$	208.25	2,142,958	$	5,262,824,022
	3,894,420	$	205.41	3,894,420	$	5,262,824,022

(1)Does not include commissions or other costs 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 for a total of $20.0 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 2020.

In connection with the Ireland Reorganization, the Class A ordinary shares of Aon Global Limited were cancelled and the holders thereof were issued an aggregate of approximately 231 million Class A ordinary shares of Aon plc. The terms and conditions of the issuance were sanctioned by the High Court of Justice in England and Wales after a hearing upon the fairness thereof at which all shareholders of Aon Global Limited had a right to appear and of which adequate notice had been given. The issuance was exempt from the registration requirements of the Securities Act of 1933, as amended, by virtue of Section 3(a)(10) thereof.

Item 6.    Selected Financial Data

Not applicable.

29

Item 7.    Management’s Discussion and Analysis of Financial Condition and Results of Operations

EXECUTIVE SUMMARY OF 2020 FINANCIAL RESULTS

Aon is a leading global professional services firm providing a broad range of risk, retirement, and health solutions underpinned by proprietary data and analytics. Management continues to lead its set of initiatives designed to strengthen Aon and unite the firm with one portfolio of capability enabled by proprietary data and analytics and one operating model to deliver additional insight, connectivity, and efficiency.

Financial Results

The following is a summary of our 2020 financial results from continuing operations:

•Revenue increased $53 million, or 0%, to $11,066 million in 2020 compared to 2019, reflecting 1% organic revenue growth, offset by a 1% unfavorable impact from divestitures, net of acquisitions. Organic revenue growth for the year was driven by strength in the core portions of the business, partially offset by a decline in the more discretionary portions.

•Operating expenses decreased $559 million, or 6%, to $8,285 million in 2020 compared to 2019 due primarily to a $451 million decrease in restructuring charges, a $138 million decrease from accelerated amortization related to certain tradenames that were fully amortized in the second quarter, expense discipline in an effort to proactively manage liquidity due to uncertainties surrounding COVID-19 and its impact on the Company, including lower travel and entertainment expense, and a $42 million favorable impact from translating prior year period results at current period foreign exchange rates (“foreign currency translation”), partially offset by $123 million of transaction costs related to the pending combination with WTW and a $37 million increase in expenses related to acquisitions, net of divestitures.

•Operating margin increased to 25.1% in 2020 from 19.7% in 2019. The increase in operating margin from the prior year is primarily driven by organic revenue growth of 1% and a decrease in operating expenses as listed above.

•Due to the factors set forth above, net income from continuing operations was $2,017 million in 2020, an increase of $443 million, or 28%, from 2019.

•Diluted earnings per share from continuing operations was $8.45 per share during the twelve months of 2020 compared to $6.37 per share for the prior year period.

•Cash flows provided by operating activities was $2,783 million in 2020, an increase of $948 million, or 52%, from $1,835 million in 2019, primarily due to working capital improvements, including improved collections and actions taken to proactively manage liquidity, a $288 million decrease in restructuring cash outlays, and strong operational improvement. The prior year period included approximately $130 million of net cash payments related to legacy litigation.

We focus on four key non-GAAP metrics that we communicate to shareholders: organic revenue growth (decline), adjusted operating margins, adjusted diluted earnings per share, and free cash flows. These non-GAAP metrics should be viewed in addition to, not instead of, our Consolidated Financial Statements and Notes thereto (the “Consolidated Financial Statements”). The following is our measure of performance against these four metrics from continuing operations for 2020:

•Organic revenue growth (decline), a non-GAAP measure defined under the caption “Review of Consolidated Results — Organic Revenue Growth (Decline),” was 1% in 2020, compared to 6% organic growth in the prior year. Organic revenue growth was driven by strength in the core portions of our business, partially offset by a decline in the more discretionary portions.

•Adjusted operating margin, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Operating Margin,” was 28.5% in 2020, compared to 27.5% in the prior year. The increase in adjusted operating margin primarily reflects expense discipline, including lower travel and entertainment expense, increased operating leverage across the portfolio, and 1% organic revenue growth, partially offset by a $47 million decrease in fiduciary investment income and an unfavorable impact from foreign currency translation of $12 million.

30

•Adjusted diluted earnings per share from continuing operations, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Diluted Earnings per Share,” was $9.81 per share in 2020, an increase of $0.64 per share, or 7%, from $9.17 per share in 2019. The increase in adjusted diluted earnings per share primarily reflects strong operational performance and effective capital management, highlighted by $1.8 billion of share repurchase during 2020, partially offset by an unfavorable impact from foreign currency translation.

•Free cash flow, a non-GAAP measure defined under the caption “Review of Consolidated Results — Free Cash Flow,” was $2,642 million in 2020, an increase of $1,032 million, or 64%, from $1,610 million in 2019, driven by an increase of $948 million in cash flows from operations and a $84 million decrease in capital expenditures. The prior year included $75 million of capital expenditures related to the restructuring program.

IRELAND REORGANIZATION

For a description of the Ireland Reorganization, see Part I, Item 1. “Business - Ireland Reorganization” in this report.

BUSINESS COMBINATION AGREEMENT

On March 9, 2020, Aon and WTW, entered into a Business Combination Agreement with respect to a combination of the parties. At the effective date of the Combination, WTW shareholders will be entitled to receive 1.08 newly issued Class A ordinary shares of Aon in exchange for each ordinary share of WTW held by such holders. The Combination is subject to Irish Takeover Rules. The Business Combination Agreement contains certain operating covenants relating to the conduct of business of both parties in the interim period until the transaction is completed. These covenants require both parties to operate their respective businesses in all material respects in the ordinary course of business consistent with past practice. In addition, these covenants restrict each party from engaging in certain actions unless a party obtains the prior written consent of the other party. These actions relate to, among other things, authorizing or paying dividends above a specified rate; issuing or authorizing for issuance additional securities; salary, benefits or other compensation and employment-related matters; capital management, debt and liquidity matters; engaging in mergers, acquisitions and dispositions; entering into or materially modifying material agreements; entering into material litigation-related settlements; and making other corporate, tax and accounting changes. The parties’ respective shareholders approved the Combination on August 26, 2020. On October 30, 2020, Aon and WTW amended the Business Combination Agreement to provide that, at the effective date of the transaction, there will be 12 members of Aon’s Board of Directors, including one director mutually agreed by the parties.

The parties continue to work with regulators, including the Antitrust Division of the U.S. Department of Justice (which, as previously disclosed, has delivered a “Second Request” pursuant to the HSR Act) and the European Commission (which, as previously disclosed, has initiated a Phase II review of the Combination) to obtain the required approvals to close the Combination. Aon expects to close the Combination in the first half of 2021, subject to regulatory approval and customary closing conditions.

RECENT DEVELOPMENTS

The outbreak of the coronavirus, COVID-19, was declared by the World Health Organization to be a pandemic and has continued to spread across the globe, impacting almost all countries, in varying degrees, creating significant public health concerns, and significant volatility, uncertainty and economic disruption in every region in which we operate. While countries are in various stages of business and travel restrictions to address the COVID-19 pandemic, as well as related re-openings, these policies have impacted and will continue to impact worldwide economic activity and may continue to adversely affect our business. We continue to closely monitor the situation and our business, liquidity, and capital planning initiatives. We continue to be fully operational and continue to reoccupy certain offices in phases, where deemed appropriate and in compliance with governmental restrictions considering the impact on health and safety of our colleagues, their families, and our clients. For other areas where restrictions remain in place or where we have started to see a resurgence of COVID-19, we are closely monitoring the situation and continuously reevaluating our plan to return to the workplace. We continue to deploy business continuity protocols to facilitate remote working capabilities to ensure the health and safety of our colleagues and to comply with public health and travel guidelines and restrictions.

As the situation continues to evolve, and the scale and duration of disruption cannot be predicted, it is not possible to quantify or estimate the full impact that COVID-19 will have on our business. We are focused on navigating these challenges and potential future impacts to our business presented by COVID-19 through preserving our liquidity and managing our cash flow by taking proactive steps to enhance our ability to meet our short-term liquidity needs and support a commitment to no layoffs of our colleagues due to COVID-19. Such actions include, but are not limited to, issuing $1 billion of our new 10-year senior unsecured notes on May 12, 2020 and using the proceeds to repay short-term debt and for other corporate purposes, and reducing our discretionary spending, including limiting discretionary spending on mergers and acquisitions. We also temporarily suspended our share buyback program and temporarily reduced compensation for named executive officers,

31

directors, and colleagues during the second quarter, as a precautionary measure, focusing on implementing cash and expense discipline measures. After carefully monitoring the situation, we determined it was appropriate, based on macroeconomic conditions and business performance, to resume share buyback during the third quarter. In addition, temporarily reduced salaries for non-executives were restored at the end of the second quarter and withheld salaries, plus 5% of the withheld salary amounts, were repaid in the third quarter. Temporarily reduced salaries for named executive officers and cash compensation reductions for non-executive directors were fully reinstated and the withheld amounts were paid in full during the fourth quarter.

While the ultimate public health and economic impact of the COVID-19 pandemic is highly uncertain, we expect that our business operations and results of operations, including our net revenues, earnings, and cash flows, will be adversely impacted, depending on the duration and severity of the downturn, as well as governmental or other regulatory policies and actions that may impact our business or operations. Our revenues can be generalized into two categories: core and more discretionary arrangements. Core revenues tend to be highly-recurring and non-discretionary, where the services are typically regulated, required, or necessary costs of managing the risk of doing business. As expected, in the fourth quarter of 2020 our core revenues did not experience a significant decrease due to the impacts of COVID-19; however, if the economic downturn becomes more severe, we expect that certain services within our core business may be negatively impacted as well. More discretionary revenues tend to include project-related services, where as expected, in the fourth quarter of 2020 we saw an impact from decreases in revenue due to the impacts of COVID-19. The impacts of the pandemic on our business operations and results of operations for the fourth quarter of 2020 are further described in the section entitled “Review of Consolidated Results” and “Liquidity and Financial Condition” contained in Part II, Item 7 of this report.

32

REVIEW OF CONSOLIDATED RESULTS

Summary of Results

Our consolidated results are as follow:

	Years ended December 31
(millions)	2020		2019		2018
Revenue
Total revenue	$	11,066	$	11,013	$	10,770
Expenses
Compensation and benefits	5,905		6,054		6,103
Information technology	444		494		484
Premises	291		339		370
Depreciation of fixed assets	167		172		176
Amortization and impairment of intangible assets	246		392		593
Other general expense	1,232		1,393		1,500
Total operating expenses	8,285		8,844		9,226
Operating income	2,781		2,169		1,544
Interest income	6		8		5
Interest expense	(334)		(307)		(278)
Other income (expense)	12		1		(25)
Income from continuing operations before income taxes	2,465		1,871		1,246
Income tax expense	448		297		146
Net income from continuing operations	2,017		1,574		1,100
Net income (loss) from discontinued operations	1		(1)		74
Net income	2,018		1,573		1,174
Less: Net income attributable to noncontrolling interests	49		41		40
Net income attributable to Aon shareholders	$	1,969	$	1,532	$	1,134
Diluted net income per share attributable to Aon shareholders
Continuing operations	$	8.45	$	6.37	$	4.29
Discontinued operations	—		—		0.30
Net income	$	8.45	$	6.37	$	4.59
Weighted average ordinary shares outstanding - diluted	233.1		240.6		247.0

Consolidated Results for 2020 Compared to 2019

Revenue

Total revenue increased $53 million, or 0%, to $11,066 million in 2020, compared to $11,013 million in 2019. The increase was driven by 1% organic revenue growth, partially offset by a 1% unfavorable impact from divestitures, net of acquisitions. Organic revenue growth for the year was driven by strength in the core portions of the business, partially offset by a decline in the more discretionary portions.

Commercial Risk Solutions revenue increased $17 million, or less than 1%, to $4,690 million in 2020, compared to $4,673 million in 2019. Organic revenue growth was 3% in 2020, driven by growth across most major geographies, including solid growth in the U.S. and Canada and double-digit growth in Latin America, driven by strong retention and management of the renewal book portfolio, partially offset by a decline in the more discretionary portions of our book globally. On average globally, exposures and pricing were both modestly positive, resulting in a modestly positive market impact overall.

Reinsurance Solutions revenue increased $128 million, or 8%, to $1,814 million in 2020, compared to $1,686 million in 2019. Organic revenue growth was 10% in 2020 driven by double-digit growth in treaty and in facultative placements, reflecting continued net new business generation. In addition, market impact was modestly positive on results.

33

Retirement Solutions revenue decreased $64 million, or 4%, to $1,753 million in 2020, compared to $1,817 million in 2019. Organic revenue decline was 2% in 2020 driven primarily by a decline in Human Capital for rewards and assessment services and a modest decline in the discretionary portions of Retirement and Investments, partially offset by growth in the core portions of Retirement and Investments.

Health Solutions revenue decreased $12 million, or 1%, to $1,655 million in 2020, compared to $1,667 million in 2019. Organic revenue decline was 1% in 2020 driven by a decrease primarily related to COVID-19, including a reduction primarily reflecting the annualized impact of lower employment levels and lower renewals, and a decline in the more discretionary portions of the business. Results were further negatively impacted by a one-time adjustment of $16 million related to revenue that was recorded across multiple years and was identified in connection with the implementation of a new system, partially offset by growth internationally.

Data & Analytic Services revenue decreased $13 million, or 1%, to $1,171 million in 2020, compared to $1,184 million in 2019. Organic revenue decline was 5% in 2020 driven by a decrease in the travel and events practice globally.

Compensation and Benefits

Compensation and benefits decreased $149 million, or 2%, in 2020 compared to 2019. The decrease was primarily driven by a $205 million decrease in restructuring charges and a $26 million favorable impact from foreign currency translation, partially offset by a $17 million increase in expenses related to acquisitions, net of divestitures, and an increase in expense associated with 1% organic revenue growth.

Information Technology

Information technology, which represents costs associated with supporting and maintaining our infrastructure, decreased $50 million, or 10%, in 2020 compared to 2019. The decrease was primarily driven by a $39 million decrease in restructuring charges and expense discipline.

Premises

Premises, which represents the cost of occupying offices in various locations throughout the world, decreased $48 million, or 14%, in 2020 compared to 2019. The decrease was primarily driven by a $33 million decrease in restructuring charges and a decrease related to reduced office occupancy.

Depreciation of Fixed Assets

Depreciation of fixed assets primarily relates to software, leasehold improvements, furniture, fixtures and equipment, computer equipment, buildings, and automobiles. Depreciation of fixed assets decreased $5 million, or 3%, in 2020 compared to 2019. The decrease was primarily driven by a $14 million decrease in restructuring charges.

Amortization and Impairment of Intangible Assets

Amortization and impairment of intangibles primarily relates to finite-lived tradenames and customer-related, contract-based, and technology assets. Amortization and impairment of intangibles decreased $146 million, or 37%, in 2020 compared to 2019. The decrease was primarily driven by a $138 million decrease from accelerated amortization related to certain tradenames that were fully amortized in the second quarter.

Other General Expenses

Other general expenses decreased $161 million, or 12%, in 2020 compared to 2019. The decrease was primarily driven by a $160 million decrease in restructuring charges and a temporary reduction of certain expenses, primarily travel and entertainment, partially offset by $123 million of transaction costs related to the pending combination with WTW and a $13 million increase in expenses related to acquisitions, net of divestitures.

Interest Income

Interest income represents income earned on operating cash balances and other income-producing investments. It does not include interest earned on funds held on behalf of clients. Interest income was $6 million in 2020, a decrease of $2 million, or 25%, from 2019, reflecting the currency composition of operating cash.

Interest Expense

Interest expense, which represents the cost of our debt obligations, was $334 million in 2020, an increase of $27 million, or 9%, from 2019. The increase was driven primarily by higher outstanding debt balances.

34

Other Income (Expense)

Total other income was $12 million in 2020, compared to other income of $1 million in 2019. Other income in 2020 primarily includes a $25 million gain on the sale of certain businesses, $13 million of pension and other postretirement income, and $4 million of equity earnings, partially offset by $12 million of losses due to the unfavorable impact of exchange rates on the remeasurement of assets and liabilities in non-functional currencies, $11 million of losses on financial instruments used to economically hedge gains and losses from changes in foreign exchange rates, and $7 million of expense related to the prepayment of $600 million Senior Notes due September 2020. Other income in 2019 primarily includes a $13 million gain on the sale of certain businesses, $9 million of gains due to the favorable impact of exchange rates on the remeasurement of assets and liabilities in non-functional currencies, $9 million of pension and other postretirement income, and $4 million of equity earnings, partially offset by $34 million of losses on financial instruments used to economically hedge gains and losses from changes in foreign exchange rates.

Income from Continuing Operations before Income Taxes

Due to factors discussed above, income from continuing operations before income taxes was $2,465 million in 2020, a 32% increase from $1,871 million in 2019.

Income Taxes from Continuing Operations

The effective tax rate on net income from continuing operations was 18.2% in 2020 and 15.9% in 2019. The primary driver of the 2020 tax rate is the geographical distribution of income, as well as net favorable discrete items including the impact of share-based payments.

The 2019 tax rate was primarily driven by the geographical distribution of income including restructuring charges, as well as net favorable discrete items including the impact of share-based payments.

Net Income from Discontinued Operations

Net income from discontinued operations was $1 million in the twelve months ended December 31, 2020, compared to a net loss from discontinued operations of $1 million in 2019.

Net Income Attributable to Aon Shareholders

Net income attributable to Aon shareholders increased to $1,969 million, or $8.45 per diluted share, in 2020, compared to $1,532 million, or $6.37 per diluted share, in 2019.

Consolidated Results for 2019 Compared to 2018

We have elected not to include a discussion of our consolidated results for 2019 compared to 2018 in this report in reliance upon Instruction 1 to Item 303(a) of Regulation S-K. This discussion can be found in our Annual Report on Form 10-K for the year ended December 31, 2019, which was filed with the SEC on February 14, 2020.

Non-GAAP Metrics

In our discussion of consolidated results, we sometimes refer to certain non-GAAP supplemental information derived from consolidated financial information specifically related to organic revenue growth (decline), adjusted operating margin, adjusted diluted earnings per share, free cash flow, and the impact of foreign exchange rate fluctuations on operating results. This non-GAAP supplemental information should be viewed in addition to, not instead of, our Consolidated Financial Statements.

35

Organic Revenue Growth (Decline)

We use supplemental information related to organic revenue growth (decline) to help us and our investors evaluate business growth from existing operations. Organic revenue growth (decline) is a non-GAAP measure that includes the impact of intercompany activity and excludes the impact of changes in foreign exchange rates, fiduciary investment income, acquisitions, divestitures, transfers between revenue lines, and gains or losses on derivatives accounted for as hedges. This supplemental information related to organic revenue growth (decline) represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, our Consolidated Financial Statements. Industry peers provide similar supplemental information about their revenue performance, although they may not make identical adjustments. A reconciliation of this non-GAAP measure to the reported Total revenue is as follows (in millions, except percentages):

	Twelve Months Ended
	Dec 31, 2020		Dec 31, 2019		% Change		Less: Currency Impact(1)		Less: Fiduciary Investment Income(2)		Less: Acquisitions, Divestitures & Other		Organic Revenue Growth (Decline)(3)
Commercial Risk Solutions	$	4,690	$	4,673	—	%	—	%	—	%	(3)	%	3	%
Reinsurance Solutions	1,814		1,686		8		—		(1)		(1)		10
Retirement Solutions	1,753		1,817		(4)		—		—		(2)		(2)
Health Solutions	1,655		1,667		(1)		(2)		—		2		(1)
Data & Analytic Services	1,171		1,184		(1)		—		—		4		(5)
Elimination	(17)		(14)		N/A		N/A		N/A		N/A		N/A
Total revenue	$	11,066	$	11,013	—	%	—	%	—	%	(1)	%	1	%

	Twelve Months Ended
	Dec 31, 2019		Dec 31, 2018		% Change		Less: Currency Impact(1)		Less: Fiduciary Investment Income(2)		Less: Acquisitions, Divestitures & Other		Organic Revenue Growth (Decline)(3)
Commercial Risk Solutions	$	4,673	$	4,652	—	%	(3)	%	—	%	(4)	%	7	%
Reinsurance Solutions	1,686		1,563		8		(2)		1		(1)		10
Retirement Solutions	1,817		1,865		(3)		(2)		—		(3)		2
Health Solutions	1,667		1,596		4		(3)		—		2		5
Data & Analytic Services	1,184		1,105		7		(3)		—		6		4
Elimination	(14)		(11)		NA		NA		NA		NA		NA
Total revenue	$	11,013	$	10,770	2	%	(3)	%	—	%	(1)	%	6	%

(1)Currency impact is determined by translating prior period's revenue at this period's foreign exchange rates.

(2)Fiduciary investment income for the years ended December 31, 2020, 2019, and 2018 was $27 million, $74 million, and $53 million, respectively.

(3)Organic revenue growth (decline) includes the impact of intercompany activity, changes in foreign exchange rates, fiduciary investment income, acquisitions, divestitures, transfers between revenue lines, and gains or losses on derivatives accounted for as hedges.

36

Adjusted Operating Margin

We use adjusted operating margin as a non-GAAP measure of core operating performance of the Company. Adjusted operating margin excludes the impact of certain items, as listed below, because management does not believe these expenses reflect our core operating performance. This supplemental information related to adjusted operating margin represents a measure not in accordance with U.S. GAAP, and should be viewed in addition to, not instead of, our Consolidated Financial Statements.

A reconciliation of this non-GAAP measure to reported operating margins is as follows (in millions, except percentages):

	Years ended December 31
	2020			2019			2018
Revenue from continuing operations	$	11,066		$	11,013		$	10,770
Operating income from continuing operations	$	2,781		$	2,169		$	1,544
Restructuring	—			451			485
Amortization and impairment of intangible assets (1)	246			392			593
Legacy litigation (2)	—			13			75
Transaction costs (3)	123			—			—
Operating income from continuing operations - as adjusted	$	3,150		$	3,025		$	2,697
Operating margin from continuing operations	25.1		%	19.7		%	14.3		%
Operating margin from continuing operations - as adjusted	28.5		%	27.5		%	25.0		%

(1)Included in the twelve months ended December 30, 2018 was a $176 million non-cash impairment charge taken on certain assets and liabilities held for sale.

(2)During the fourth quarter of 2019 we settled legacy litigation that had been reported in a prior year as an adjustment to GAAP earnings. In connection with the settlement, we recorded a $13 million charge in 2019, which represents the difference between the amount accrued in the prior year and the final settlement amount of the legacy litigation.

(3)Certain transaction costs associated with the Combination will be incurred prior to the expected completion of the Combination in the first half of 2021. These costs may include advisory, legal, accounting, valuation, and other professional or consulting fees required to complete the Combination.

Adjusted Diluted Earnings per Share

We use adjusted diluted earnings per share as a non-GAAP measure of our core operating performance. Adjusted diluted earnings per share excludes the items identified above, along with pension settlements and related income taxes, because management does not believe these expenses are representative of our core earnings. This supplemental information related to adjusted diluted earnings per share represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, our Consolidated Financial Statements.

37

A reconciliation of this non-GAAP measure to reported diluted earnings per share is as follows (in millions, except per share data and percentages):

	Year Ended December 31, 2020
(millions, except per share data)	U.S. GAAP			Adjustments		Non-GAAP Adjusted
Operating income from continuing operations	$	2,781		$	369	$	3,150
Interest income	6			—		6
Interest expense	(334)			—		(334)
Other income (expense) (1)	12			—		12
Income before income taxes from continuing operations	2,465			369		2,834
Income tax expense (2)	448			51		499
Net income from continuing operations	2,017			318		2,335
Net income (loss) from discontinued operations (3)	1			—		1
Net income	2,018			318		2,336
Less: Net income attributable to noncontrolling interests	49			—		49
Net income attributable to Aon shareholders	$	1,969		$	318	$	2,287
Diluted net income per share attributable to Aon shareholders
Continuing operations	$	8.45		$	1.36	$	9.81
Discontinued operations	—			—		—
Net income	$	8.45		$	1.36	$	9.81
Weighted average ordinary shares outstanding — diluted	233.1			—		233.1
Effective tax rates (2)
Continuing operations	18.2		%			17.6		%
Discontinued operations	24.1		%			24.1		%

	Year Ended December 31, 2019
(millions, except per share data)	U.S. GAAP			Adjustments		Non-GAAP Adjusted
Operating income from continuing operations	$	2,169		$	856	$	3,025
Interest income	8			—		8
Interest expense	(307)			—		(307)
Other income (expense) (1)	1			—		1
Income before income taxes from continuing operations	1,871			856		2,727
Income tax expense (2)	297			181		478
Net income from continuing operations	1,574			675		2,249
Net income (loss) from discontinued operations (3)	(1)			—		(1)
Net income	1,573			675		2,248
Less: Net income attributable to noncontrolling interests	41			—		41
Net income attributable to Aon shareholders	$	1,532		$	675	$	2,207
Diluted net income (loss) per share attributable to Aon shareholders
Continuing operations	$	6.37		$	2.80	$	9.17
Discontinued operations	—			—		—
Net income	$	6.37		$	2.80	$	9.17
Weighted average ordinary shares outstanding — diluted	240.6			—		240.6
Effective tax rates (2)
Continuing operations	15.9		%			17.5		%
Discontinued operations	47.4		%			47.4		%

38

	Year Ended December 31, 2018
(millions, except per share data)	U.S. GAAP		Adjustments		Non-GAAP Adjusted
Operating income from continuing operations	$	1,544	$	1,153	$	2,697
Interest income	5		—		5
Interest expense	(278)		—		(278)
Other income (expense) (1)	(25)		37		12
Income before income taxes from continuing operations	1,246		1,190		2,436
Income tax expense (2)	146		233		379
Net income from continuing operations	1,100		957		2,057
Net income (loss) from discontinued operations (3)	74		(82)		(8)
Net income	1,174		875		2,049
Less: Net income attributable to noncontrolling interests	40		—		40
Net income attributable to Aon shareholders	$	1,134	$	875	$	2,009
Diluted net income (loss) per share attributable to Aon shareholders
Continuing operations	$	4.29	$	3.87	$	8.16
Discontinued operations	0.30		(0.33)		(0.03)
Net income	$	4.59	$	3.54	$	8.13
Weighted average ordinary shares outstanding — diluted	247.0		—		247.0
Effective tax rates (2)
Continuing operations	11.7