2023 Irish Statutory Accounts

• the failure to retain, attract and develop experienced and qualified personnel;
• international risks associated with our global operations, including impacts from military conflicts or political instability, such as the ongoing Russian war in Ukraine and the Israel-Hamas conflict;
• the effects of natural or man-made disasters, including the effects of health pandemics and the impacts of climate- related events;
• any system or network disruption or breach resulting in operational interruption or improper disclosure of confidential, personal, or proprietary data, and resulting liabilities or damage to our reputation;
• our ability to develop, implement, update, and enhance new technology;
• the actions taken by third parties that perform aspects of our business operations and client services;
• the extent to which we are exposed to certain risks, including lawsuits, related to our actions we may take in being responsible for making decisions on behalf of clients in our investment businesses or in other advisory services that we currently provide, or will provide in the future;
• our ability to continue, and the costs and risks associated with growing, developing and integrating acquired business, and entering into new lines of business or products;
• our ability to secure regulatory approval and complete transactions, and the costs and risks associated with the failure to consummate proposed transactions;
• changes in commercial property and casualty markets, commercial premium rates or methods of compensation;
• our ability to develop and implement innovative growth strategies and initiatives intended to yield cost savings (including the Accelerating Aon United Program) and the ability to achieve such growth or cost savings;
• the effects of Irish law on our operating flexibility and the enforcement of judgments against us;
• adverse effects on the market price of Aon's securities and/or operating results for any reason, including, without limitation, because of the failure to realize the expected benefits of the acquisition of NFP (including anticipated revenue and growth synergies) in the expected timeframe, or at all;
• significant transaction and integration costs or difficulties in connection with the acquisition of NFP or unknown or inestimable liabilities; and
• potential impact of the consummation of the acquisition of NFP on relationships, including with suppliers, customers, employees and regulators.

Any or all of our forward-looking statements may tuout 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 "Principal Risks and Uncertainties" section in the Directors' Report section of this report.

3

4

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

5

DIRECTORS' REPORT

The directors present their annual report together with the consolidated group financial statements of Aon plc (the "Parent Company" or "Aon plc") and its subsidiaries (which together may be referred to as "Aon," the "Company," "Group," "we," "us," or "our") for the year ended December 31, 2023, as well as the Parent Company financial statements for the year ended December 31, 2023.

The directors have elected to prepare the consolidated group financial statements in accordance with section 279 of the Companies Act 2014 of Ireland, as amended (the "Irish Companies Act"), which provides that a true and fair view of the assets and liabilities, financial position and profit or loss of the Group may be given by preparing the financial statements in accordance with the accounting principles generally accepted in the U.S. ("U.S. GAAP"), to the extent that the use of those principles in the preparation of the financial statements does not contravene any provision of Part 6 of the Irish Companies Act. While the consolidated group financial statements are prepared in accordance with U.S. GAAP, the financial reporting framework that has been applied in the preparation of the Parent Company financial statements is applicable Irish Companies Act and the Financial Reporting Standard applicable in the UK and Republic of Ireland issued in the UK by the Financial Reporting Council ("FRS 102"), effective for the 2023 year-end.

Basis of Presentation

The accompanying Consolidated Financial Statements include the Consolidated Profit and Loss Accounts, Statements of Comprehensive Income, Statements of Financial Position, Statements of Shareholders' Equity, and Statements of Cash Flows of Aon plc and its subsidiaries as of and for the years ended December 31, 2023 and December 31, 2022. The Parent Company Financial Statements include the Statements of Comprehensive Income, Statements of Financial Position, and Statements of Shareholders' Equity of the Parent Company as of and for the years ended December 31, 2023 and December 31, 2022.

Directors of the Parent Company

Gregory C. Case

Lester B. Knight

Jin-Yong Cai

Jeffrey C. Campbell

Fulvio Conti

Cheryl A. Francis

Adriana Karaboutis

J. Michael Losh (1)

Richard C. Notebaert

Gloria Santona

Sarah Smith

Byron O. Spruell

Carolyn Y. Woo (2)

1. J. Michael Losh retired from the Parent Company's Board of Directors effective at the Parent Company's 2023 Annual General Meeting held on June 22, 2023.
2. On February 13, 2024 Carolyn Y. Woo informed the Parent Company of her decision to retire from the Parent Company's Board of Directors, effective upon the completion of her current term at the time of the Parent Company's 2024 Annual General Meeting

Effective January 24, 2024, the Parent Company appointed Jose Antonio Álvarez to the Board of Directors.

PRINCIPAL ACTIVITIES

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

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

6

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 retuon invested capital.

On April 25, 2024, the Company completed its acquisition of NFP, a leading middle-market provider of property and casualty brokerage, benefits consulting, wealth management, and retirement plan consulting, with more than 7,700 colleagues. The Company acquired NFP Intermediate Holdings A Corp. in a cash-and-stock merger for an aggregate preliminary purchase price totaling $9.1 billion, with approximately $3.2 billion to settle NFP indebtedness and cash consideration to the selling shareholders, and approximately 19 million class A ordinary shares with a fair value of approximately $5.9 billion.

BUSINESS SEGMENT

We operate as one segment that includes all of our continuing operations, which, as a global professional services firm, provides a broad range of risk and human capital solutions through four solution lines - Commercial risk, Reinsurance, Health, and Wealth, which make up our principal products and services. The CODM assesses the performance of the Company and allocates resources based on one segment: Aon United.

In 2023, our consolidated total revenue was $13,376 million. This includes $7,043 million in Commercial Risk Solutions, $2,481 million in Reinsurance Solutions, $2,433 million in Health Solutions, and $1,431 million in Wealth Solutions, before certain intercompany eliminations.

In 2022, our consolidated total revenue was $12,479 million. This includes $6,715 million in Commercial Risk Solutions, $2,190 million in Reinsurance Solutions, $2,224 million in Health Solutions, and $1,367 million in Wealth Solutions, before certain intercompany eliminations.

Principal Products and Services

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. In retail brokerage, our dedicated teams of risk professionals utilize comprehensive analytics capabilities and insights providing clients with risk advice for their organizations. We utilize Aon's differentiated capabilities in industry sector- and segment-specific approaches, like Digital Client Solutions, to risk transfer options and deliver them through a variety of channels including bespoke solutions for complex needs, structured solutions for mid-market and small and medium- sized enterprises, and digital distribution including CoverWallet. Our specialty-focused organizational structure includes financial and professional lines, cyber, surety and trade credit, crisis management, transaction liability, climate, and intellectual property. We develop market leading insights on the most efficient risk transfer vehicles for clients in today's complex and integrated risk environment to enable clients to make better decisions. Global risk consulting and captive management is a global leader in supporting better management of companies' risk profiles by identifying and quantifying the risks they face, mapping out optimal risk mitigation, retention and transfer solutions and thus enabling them to be more informed to make better decisions for their businesses. Affinity programs include development, marketing, and administration of customized and targeted insurance programs, facilities, and other structured solutions, including Aon Client Treaty. We collaborate with sponsors and other privileged distribution channels through which Aon can deliver differentiated, highly targeted, and highly valuable solutions for unique risk solutions.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, Strategy and Technology Group and capital markets. Treaty reinsurance addresses underwriting and capital objectives on a portfolio level, allowing our clients to more effectively manage the combination of premium growth, retuon capital, and rating agency interests on an integrated basis. This includes the development of more competitive, innovative, and efficient risk transfer options. Facultative reinsurance empowers clients to better understand, manage, and transfer risk through innovative facultative solutions and provides the most efficient access to the global facultative reinsurance markets. Strategy and Technology Group combines strategic advice with data-driven consulting, analytics, and modeling tools, including Tyche, ReMetrica, and PathWise, to help clients deploy capital efficiently and effectively. We develop highly customized solutions that help clients drive growth and operational efficiency, improve balance sheet strength and resiliency, and comply with regulatory and operational requirements, including through the execution of reinsurance transactions. Capital markets is a global investment bank with expertise in insurance-linked securities, capital raising, strategic advice, restructuring, and mergers and acquisitions. We partner with insurers, reinsurers, investment firms, and corporations in executing innovative risk management products, capital market solutions and corporate finance advisory services.

Health Solutions includes consulting and brokerage, consumer benefits solutions, and talent. Consulting and brokerage develops and implements innovative, customized health and benefits strategies for clients of all sizes across industries and geographies to manage risk, drive engagement, and strengthen the workforce through improved health and wellbeing. We partner with insurers and other strategic partners to develop and implement new and innovative solutions and leverage world-

7

class analytics and technology to help clients make informed decisions and manage healthcare outcomes. Consulting and brokerage also advises multinational companies on global benefits, including insurance placement across more than 120 countries and sovereignties, program design and management, financing optimization, and enhanced employee experience, as well as assists in navigating global regulatory and compliance requirements in countries in which they operate. Consumer benefits solutions designs and delivers innovative voluntary consumer benefits that improve an employer's total rewards strategy and positively impacts their employees' financial and overall wellbeing. We leverage our proprietary digital platform to provide efficient enrollment strategies through an effective combination of data, analytics, and tailored products. Multi-channel and targeted communications solutions increase consumer benefit knowledge and enhance engagement. Our talent team delivers data, analytics, and advice to business leaders so they can make better workforce decisions and align their business and people strategies. We support clients across the full employee lifecycle, including talent assessment and selection, compensation benchmarking, total rewards strategy optimization, workforce analytics and benchmarking, workforce resilience planning, talent integration in transaction situations, Corporate Governance, ESG consulting, and strategic employee communication.

Wealth Solutions includes retirement consulting, pension administration, and investments consulting. Retirement consulting specializes in providing clients 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. We also help organizations manage their balance sheet volatility. Retirement consulting and pension administration leverage Aon's pension expertise to deliver high-quality integrated retirement services. Our customized services include outsourcing, co-sourcing and in-sourcing options. Our partnership-driven model is powered by deep pension experience and enabled with smart technology. Our investments consulting team 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. 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. We partner with clients to deliver our scale and experience to help them effectively manage their investments, risk, and governance and potentially lower costs. We believe in the power of connecting participants to experts to make better informed and smarter decisions about their wealth.

Revenue and Compensation

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

Funds Held on Behalf of Clients

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

Competition

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

Seasonality

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

8

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 Principal Risks and Uncertainties section of this report for information regarding how actions by regulatory authorities or changes in legislation and regulation in the jurisdictions in which we operate may have an adverse effect on our business.

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

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

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

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

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

Further, pension and financial laws and regulations, including oversight and supervision by the FCA in the U.K., the SEC and the DOL in the U.S., and regulators in other countries govecertain of the retirement-related consulting services provided by Aon. This includes subsidiaries of Aon plc that provide investment advisory services regulated by various U.S. federal authorities including the SEC, DOL, and FINRA, as well as authorities on the state level. In addition, other services provided by subsidiaries and affiliates of Aon plc, 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 2023. 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 2023.

9

PRINCIPAL RISKS AND UNCERTAINTIES

The principal risks and uncertainties 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". Readers should consider these risks in addition to the other information contained in this report because our business, financial condition, or results of operations could be materially adversely affected if any of these risks were to actually occur and the occurrence of such risks could cause our actual results to differ materially from those stated in or implied by the forward-looking statements in this document and elsewhere.

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 tuis affected by the economy of the industries and markets these clients serve. Economic downturns, volatility, or uncertainty in the broader economy or in specific markets (including as a result of endemics or pandemics, climate change, political unrest, actions by central banks, or otherwise) 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 and Reinsurance Solutions 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 revenue is determined as a percentage of premiums charged to our clients. In addition, certain discretionary services within our business, such as Human Capital, project-related work within Commercial Risk Solutions and Health Solutions, and transaction services, may see a decrease in activity if the overall level of economic activity results in a reduction to our clients' discretionary spending. 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. In addition, decreased underwriting capacity for insurance and reinsurance may create difficulty for our professionals to place business, which may adversely impact our ability to earevenue.

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

As a global professional services firm, we compete with a broad variety of firms, including 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, human resources consulting, 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.

Alliances or mergers among competitors could affect our business. Further, we compete on pricing and the innovation and quality of our service offerings, which could be affected by competitors' lower cost structures, product development activities, and pricing policies, any or all of which could result in better market acceptance of our competitors' offerings than those that we offer or develop.

This competition is further intensified by an industry trend where clients elect to engage multiple brokers to service different portions of their accounts. If we fail to respond successfully to the evolving competition we face, our financial condition or results of operations might be adversely affected.

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

Developing and implementing innovative strategies, efficient business practices, and new solutions to current and emerging client needs is important to our business. We may be unsuccessful in developing innovative strategies, or our competitors may be more successful in innovating and delivering services to meet new and existing client needs. Competitors may be able to

10