Aon (AON) 10-K risk factor changes: FY2023 vs FY2022

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 [removed: reductions in the growth of new business or reductions in existing business.]

In addition, certain discretionary services within our business, such as Human Capital, project-related work within Commercial Risk Solutions and Health Solutions, and transaction [removed: liability,] [added: services,] may see a decrease in activity if the overall level of economic activity results in a reduction to our clients’ discretionary spending.

As a global professional services firm, we compete with [added: 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.

Further, we compete on pricing and the innovation and quality of our service [removed: offerings and] [added: 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.

Competitors may be able to innovate faster and respond better to evolving client demand and industry conditions, or [added: may] price their [removed: services] [added: products in a manner that clients find] more [removed: aggressively] [added: attractive] than [removed: we do.][added: Aon.]

If we are unsuccessful in innovating, if we cannot innovate as quickly as our competitors, if we are not able to make sufficient investment in innovation, if our competitors develop more cost-effective [removed: technologies,] [added: technologies (including through the use of artificial intelligence] or [added: other emerging 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 [added: Aon Business Services and] the development of [removed: our] proprietary data and analytics tools including repositories of global insurance and reinsurance placement information, which we use to [added: help] drive results for our clients in the insurance and reinsurance placement process.

Our competitors have or are developing competing data and analytics tools, and their success in this space may impact our ability to differentiate our [removed: services to our clients through the use of unique technological solutions.][added: own data and analytics tools.]

Innovations in software, cloud computing, data and [removed: analytics] [added: analytics, generative artificial intelligence,] 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.

In addition, innovation in technology, capabilities, [added: sources of capital for our clients’ insurance] and [added: reinsurance needs, and] the entry into new lines of business, services, or products require significant investment and present additional risks to the Company, particularly in instances where the markets are new or not fully [removed: developed.][added: developed or where participants in such markets are new entrants.]

Damage to our reputation, including as a result of negative perceptions or publicity regarding a class of business, environmental matters, climate change, workforce [removed: diversity,] [added: make-up,] pay equity, harassment, social justice, cyber security or data privacy, or our inability to meet commitments or client and stakeholder expectations with respect to such matters, 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.

- 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 [added: 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 premiums;]

- [added: the] 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.

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, [added: effectively] control our costs, or improve our efficiency.

[removed: 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.

Although we use various derivative financial instruments to [removed: help protect against certain adverse] [added: limit the impact of] foreign exchange rate fluctuations, we cannot eliminate such risks, and, as a result, changes in exchange rates may adversely affect our results.

Operating funds available for corporate use were [removed: $1,142] [added: $1,147] million at December 31, [removed: 2022] [added: 2023] and are reported in Cash and cash equivalents and Short-term investments.

Of the total balance, [removed: $115] [added: $120] million was restricted to its use as of December 31, [removed: 2022.][added: 2023.]

Funds held on behalf of clients and insurers were [removed: $6.4] [added: $6.9] billion at December 31, [removed: 2022] [added: 2023] and are reported in Fiduciary assets.

As of December 31, [removed: 2022,] [added: 2023,] these long-term investments had a carrying value of [removed: $60] [added: $45] million.

Variations or developments in connection with any of these factors could cause [added: significant changes to our financial position and results of operations from year to year.]

As of December 31, [removed: 2022,] [added: 2023,] we had total consolidated debt outstanding of approximately [removed: $10.8] [added: $11.2] billion.

As of December 31, [removed: 2022,] [added: 2023,] we had two committed credit facilities outstanding.

Our senior debt ratings at December 31, [removed: 2022] [added: 2023] were A- with a [removed: stable] [added: negative] outlook (S&P), BBB+ with a [removed: stable] [added: negative] outlook (Fitch), and Baa2 with a stable outlook (Moody’s).

The OECD, a global coalition of member countries, proposed a plan [added: (commonly referred] to [added: as “Pillar Two”) to] reform international taxation which includes the introduction of a [added: 15%] global minimum [removed: tax.][added: tax on book income with specified adjustments and determined on a country-by-country basis.]

The OECD [removed: recommendations have] [added: proposed tax regime has] been nominally accepted by many countries within and without the OECD, [removed: but the] [added: although] implementation in each country remains subject to the possibility of significant variation, which could lead to a risk of multiple levels of taxation on Aon’s income.

[removed: The] [added: Ireland, the] U.K. and [added: many] E.U. member states, among others, have [removed: introduced draft] [added: enacted] legislation [removed: or otherwise agreed] to implement [removed: a] [added: the] global minimum tax that [removed: would be] [added: are] consistent with the OECD [removed: recommendations, beginning, for Aon, in 2024.][added: proposed tax regime.]

[removed: If and when effective,] [added: - The implementation of] the [added: OECD] global minimum tax [added: regime in Ireland] could have a material adverse effect on our global effective tax rate, results of operations, cash flows and financial condition.

We rely on dividends, interest, and other payments from these subsidiaries to meet our obligations for paying principal and interest on outstanding debt, paying dividends to shareholders, repurchasing ordinary shares, and corporate [added: expenses.]

However, we may be unable to maintain, at commercially reasonable rates, our current levels of insurance coverage for E&O claims or other risks in future [removed: periods.][added: periods, and with respect to such periods may seek to utilize self-insurance programs such as captives, the funding of which may not adequately cover the costs of potential losses.]

[added: In addition, certain laws and regulations, such as the] Foreign [added: 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.

Additionally, our acquisitions of new businesses and our continued operational changes and entry into new jurisdictions and [added: development of] new service offerings increases our legal and regulatory compliance complexity, as well as the type of governmental oversight to which we may be subject.

[removed: 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 [removed: by ,] [added: by,] regulatory bodies in jurisdictions in which we operate.

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 [added: be] fined or penalized in a given jurisdiction.

Changes in the regulatory scheme, or even changes in how [removed: existing] [added: applicable] regulations are interpreted, could have an adverse impact on our results of operations by limiting revenue streams or increasing costs of compliance.

For instance, if we are providing or managing general underwriting services for an insurer, we may have to [removed: contend with] [added: adhere to] regulations affecting our [added: insurer] client.

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 [added: contribution plans (such as 401(k)), or defined benefit plans (such as pension), may adversely affect the demand for, or profitability of, our services.]

[removed: 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.

We also [added: may] provide [added: multiple types of] services to [removed: advise and assist in satisfying all our clients’ needs] [added: certain clients] from [removed: all] [added: more than one of] our [removed: businesses,] [added: solution lines,] creating a greater potential for conflicts with advisory services.

Risk Factors Summary

The following is a summary of the principal risks associated with our businesses and the industries in which we operate generally as described in more detail in this report.

We encourage you to carefully review the full risk factors immediately following this summary as well as the other information in this report.

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

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

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

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

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

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

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

Similarly, changes in interest rates and deterioration of credit quality could reduce the value of our cash balances and investment portfolios and adversely affect our financial condition or results.

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

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

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

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

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

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

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

- 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 may not recognize all of the expected benefits from our Accelerating Aon United program and other operation improvement initiatives.

- 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 Pending Acquisition of NFP (the “Transaction”)

- The Transaction 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 Transaction could negatively impact our share price and future business and financial results.

- While the Transaction 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 Transaction.

- 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.

Risks Related to Our Business

reductions in the growth of new business or reductions in existing business.

Financial Risks

These currency exchange fluctuations create risk in both the translation of the financial

Under Ireland’s Pillar Two tax regime, starting in 2024, Aon’s net income (under U.S. GAAP), with specified modifications and determined on country-by-country basis, will be subject to the 15% minimum tax.

There remains significant uncertainty, however, as to how Ireland’s Pillar Two tax regime and the OECD’s past and potentially future Pillar Two guidance will ultimately apply to Aon.

In any event, until further clarifications are provided, there is a risk that the global minimum tax regime could have a material adverse effect on our global effective tax rate, results of operations, cash flows and financial condition.

Legal and Regulatory Risks

Furthermore, as

For instance, increased scrutiny by competition authorities may increase our costs 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 premiums;

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 “Ireland Reorganization”).

At the time of the Ireland Reorganization we expected, and we continue to expect, that the Ireland Reorganization will, among other things, provide greater certainty around ongoing access to existing U.S. treaties with other E.U. member states from which we derive benefit.

However, we may not realize the benefits we anticipate from the Ireland Reorganization, which could have an adverse effect on our business.

significant changes to our financial position and results of operations from year to year.

Countries around the world are considering changes in their tax laws and regulations.

There remains significant uncertainty as to if, when and how the various OECD proposals will ultimately be enacted.

expenses.

In addition, certain laws and regulations, such as the Foreign Corrupt Practices Act and the

contribution plans (such as 401(k)), or defined benefit plans (such as pension), may adversely affect the demand for, or profitability of, our services.

The COVID-19 global pandemic and the emergence of COVID-19 variants 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, mandates, requirements or recommendations; and uncertainties in vaccine adoption.

In addition, the continuing COVID-19 pandemic or other epidemics or pandemics, may again create significant disruptions or volatility 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 or other epidemics or pandemics 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.

Should we experience a local or regional disaster or other business continuity problem, such as a security incident or attack, a natural disaster, climate

If we dispose of or otherwise exit certain businesses, there can be no assurance that we will

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.

remediate or otherwise resolve such issues.

EXECUTIVE SUMMARY OF [removed: 2022] [added: 2023] FINANCIAL RESULTS

Aon plc is a leading global professional services firm providing a broad range of [removed: risk, health,] [added: risk] and [removed: wealth] [added: human capital] solutions.

Through our experience, global reach, and comprehensive analytics, we [removed: are better able to] help clients meet rapidly changing, increasingly complex, and interconnected [removed: challenges.][added: challenges related to risk and people.]

We are committed to accelerating innovation to address unmet and evolving client [removed: needs,] [added: needs] so that our clients are better informed, better advised, and able to make better decisions to protect and grow their business.

Management [removed: is] [added: 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.

The following is a summary of our [removed: 2022] [added: 2023] financial results:

- Revenue increased [removed: $286] [added: $897] million, or [removed: 2%,] [added: 7%,] to [removed: $12.5] [added: $13.4] billion in [removed: 2022] [added: 2023] compared to [removed: 2021,] [added: 2022,] reflecting [removed: 6%] [added: 7%] organic revenue growth and a [removed: 1%] [added: 2%] favorable impact from fiduciary investment income, partially offset by a [removed: 4% unfavorable impact from foreign currency translation a 1%] [added: 2%] unfavorable impact from acquisitions, divestitures and other.

The [removed: increase] [added: decrease] was driven by [removed: a decrease] [added: an increase] in operating expenses as listed [removed: above and organic revenue growth of 6%.][added: above.]

- Due to the factors set forth above, Net income was $2.6 billion in [removed: 2022, an increase] [added: 2023, a decrease] of [removed: $1.3 billion,] [added: $18 million,] or [removed: 102%,] [added: 1%,] from [removed: 2021.][added: 2022.]

- Diluted earnings per share increased [removed: 119%] [added: 3%] to [removed: $12.14] [added: $12.51] per share during the twelve months of [removed: 2022] [added: 2023] compared to [removed: $5.55] [added: $12.14] per share for the prior year period.

The following is our measure of performance against these four metrics for [removed: 2022:][added: 2023:]

- Organic revenue growth, a non-GAAP measure defined under the caption “Review of Consolidated Results — Organic Revenue Growth,” was [removed: 6%] [added: 7%] in [removed: 2022,] [added: 2023,] compared to [removed: 9%] [added: 6%] organic growth in the prior [removed: year.][added: year period.]

- Adjusted operating margin, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Operating Margin,” was [removed: 30.8%] [added: 31.6%] in [removed: 2022,] [added: 2023,] compared to [removed: 30.1%] [added: 30.8%] in the prior [removed: year.][added: year period.]

The increase in adjusted operating margin primarily reflects [removed: 6%] [added: 7%] organic revenue growth and [removed: a] higher fiduciary investment income, partially offset by increased expenses and investments in long-term growth.

- Adjusted diluted earnings per share, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Diluted Earnings per Share,” was [removed: $13.39] [added: $14.14] per share in [removed: 2022,] [added: 2023,] an increase of [removed: $1.39] [added: $0.75] per share, or [removed: 12%,] [added: 6%,] from [removed: $12.00] [added: $13.39] per share in [removed: 2021.][added: 2022.]

The increase in adjusted diluted earnings per share primarily reflects strong operational performance and effective capital management, highlighted by [removed: $3.2] [added: $2.7] billion of share repurchase during [removed: 2022, partially offset by an unfavorable impact from foreign currency translation.][added: 2023.]

- Free cash flow, a non-GAAP measure defined under the caption “Review of Consolidated Results — Free Cash Flow,” was [removed: $3.0] [added: $3.2] billion in [removed: 2022,] [added: 2023,] an increase of [removed: $978] [added: $160] million, or [removed: 48%,] [added: 5%,] from [removed: $2.0] [added: $3.0] billion in [removed: 2021,] [added: 2022,] reflecting an increase in Cash flows from operations, partially offset by a [removed: $59] [added: $56] million increase in capital expenditures.

For many companies, the management of ESG risks and opportunities has become increasingly important, and ESG-related challenges, such as extreme weather events, supply chain disruptions, cyber events, regulatory changes, ongoing public health impacts, and the increased focus on workforce resilience in [removed: highly varied] [added: various] work [removed: environments] [added: environments,] continue to create volatility and uncertainty for our clients.

[removed: Aon offers] [added: We offer] a wide range of risk assessment, [removed: consulting] [added: consulting,] and advisory solutions, many of which are significant parts of our core business offerings, designed to address and manage ESG issues for clients, and to enable our clients to create more sustainable value.

| | | | | | | [removed: 2022] [added: 2023] | | | | | | [removed: 2021] [added: 2022] | | | | | | [removed: 2020] [added: 2021] | | |

| Total revenue | | | | | | $ | [removed: 12,479] [added: 13,376] | | | | | $ | [removed: 12,193] [added: 12,479] | | | | | $ | [removed: 11,066] [added: 12,193] | |

| Compensation and benefits | | | | | | [removed: 6,477] [added: 6,902] | | | | | | [removed: 6,738] [added: 6,477] | | | | | | [removed: 5,905] [added: 6,738] | | |

| Information technology | | | | | | [removed: 509] [added: 534] | | | | | | [removed: 477] [added: 509] | | | | | | [removed: 444] [added: 477] | | |

| Premises | | | | | | [removed: 289] [added: 294] | | | | | | [removed: 327] [added: 289] | | | | | | [removed: 291] [added: 327] | | |

| Depreciation of fixed assets | | | | | | [removed: 151] [added: 167] | | | | | | [removed: 179] [added: 151] | | | | | | [removed: 167] [added: 179] | | |

| Amortization and impairment of intangible assets | | | | | | [removed: 113] [added: 89] | | | | | | [removed: 147] [added: 113] | | | | | | [removed: 246] [added: 147] | | |

| Other general expense | | | | | | [removed: 1,271] [added: 1,470] | | | | | | [removed: 2,235] [added: 1,271] | | | | | | [removed: 1,232] [added: 2,235] | | |

| Total operating expenses | | | | | | [removed: 8,810] [added: 9,591] | | | | | | [removed: 10,103] [added: 8,810] | | | | | | [removed: 8,285] [added: 10,103] | | |

| Operating income | | | | | | [removed: 3,669] [added: 3,785] | | | | | | [removed: 2,090] [added: 3,669] | | | | | | [removed: 2,781] [added: 2,090] | | |

| Interest income | | | | | | [removed: 18] [added: 31] | | | | | | [removed: 11] [added: 18] | | | | | | [removed: 6] [added: 11] | | |

| Interest expense | | | | | | [removed: (406)] [added: (484)] | | | | | | [removed: (322)] [added: (406)] | | | | | | [removed: (334)] [added: (322)] | | |

| Other income (expense) | | | | | | [removed: (125)] [added: (163)] | | | | | | [removed: 152] [added: (125)] | | | | | | [removed: 13] [added: 152] | | |

| Income before income taxes | | | | | | [removed: 3,156] [added: 3,169] | | | | | | [removed: 1,931] [added: 3,156] | | | | | | [removed: 2,466] [added: 1,931] | | |

| Income tax expense | | | | | | [removed: 510] [added: 541] | | | | | | [removed: 623] [added: 510] | | | | | | [removed: 448] [added: 623] | | |

| Net income | | | | | | [removed: 2,646] [added: 2,628] | | | | | | [removed: 1,308] [added: 2,646] | | | | | | [removed: 2,018] [added: 1,308] | | |

| Less: Net income attributable to noncontrolling interests | | | | | | [removed: 57] [added: 64] | | | | | | [removed: 53] [added: 57] | | | | | | [removed: 49] [added: 53] | | |

| Net income attributable to Aon shareholders | | | | | | $ | [removed: 2,589] [added: 2,564] | | | | | $ | [removed: 1,255] [added: 2,589] | | | | | $ | [removed: 1,969] [added: 1,255] | |

| Diluted net income per share attributable to Aon shareholders | | | | | | $ | [removed: 12.14] [added: 12.51] | | | | | $ | [removed: 5.55] [added: 12.14] | | | | | $ | [removed: 8.45] [added: 5.55] | |

| Weighted average ordinary shares outstanding - diluted | | | | | | [removed: 213.2] [added: 205.0] | | | | | | [removed: 226.1] [added: 213.2] | | | | | | [removed: 233.1] [added: 226.1] | | |

Total revenue increased [removed: $286] [added: $897] million, or [removed: 2%,] [added: 7%,] to [removed: $12.5] [added: $13.4] billion in [removed: 2022,] [added: 2023,] compared to [removed: $12.2] [added: $12.5] billion in [removed: 2021.][added: 2022.]

- Operating expenses increased $781 million, or 9%, to $9.6 billion in 2023 compared to 2022 due primarily to an increase in expense associated with 7% organic revenue growth, investments in long-term growth, a $197 million charge in connection with certain accrued actual or anticipated legal settlement expenses, and $135 million of expenses related to the Accelerating Aon United Restructuring Program.

- Operating margin decreased to 28.3% in 2023 from 29.4% in 2022.

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

At Aon, helping clients manage risk - including ESG risk - is at the core of what we do.

We see significant opportunity in enhancing our impact and delivering innovative client solutions on ESG matters.

DEFINITIVE ACQUISITION AGREEMENT

On December 19, 2023, Aon entered into a definitive agreement with NFP and the NFP seller, where Aon will acquire NFP for an aggregate purchase price of approximately $7 billion in cash and approximately 20,000,000 class A ordinary shares, nominal value of $0.01, in capital of Aon.

The Company expects to fund the cash portion of the consideration with approximately $7 billion of new debt, with $5 billion raised in advance of the closing date and $2 billion raised at close of the acquisition.

The acquisition is expected to be completed by mid-2024, subject to satisfaction or waiver of the closing conditions set forth in the Merger Agreement, including applicable regulatory approval.

| Accelerating Aon United Program expenses | | | | | | 135 | | | | | | — | | | | | | — | | |

Growth in retail brokerage was highlighted by double-digit growth in Asia and the Pacific, driven by continued strength in core P&C.

The U.S. grew modestly driven by strength in core areas of property, casualty, and construction, partially offset by the impact of external M&A and IPO activity.

Compensation and benefits increased $425 million, or 7%, in 2023 compared to 2022.

Depreciation of fixed assets increased $16 million, or 11%, in 2023 compared to 2022, due primarily to ongoing investments in Aon Business Services-enabled technology platforms to drive long-term growth.

Amortization and impairment of intangibles decreased $24 million, or 21%, in 2023 compared to 2022 due primarily to a decrease associated with assets held for sale in 2023 as part of ongoing portfolio management and assets fully amortized in the prior year period.

Other general expenses increased $199 million, or 16%, in 2023 compared to 2022.

The increase was due primarily to a $197 million charge in connection with certain accrued actual or anticipated legal settlement expenses.

Accelerating Aon United Program Expenses

Accelerating Aon United Program expenses were $135 million in 2023, reflecting restructuring charges associated with the Program announced in the third quarter of 2023, relating to workforce optimization, asset impairments, and technology and other costs.

The increase was driven primarily by an overall increase in total debt and higher interest rates.

Other expense was $163 million in 2023, which primarily reflects an expense from the unfavorable impact of exchange rates on the remeasurement of assets and liabilities in non-functional currencies and a non-cash net periodic pension cost.

Income before income taxes was flat at $3.2 billion in 2023, compared to the prior year period.

The 2023 tax rate was primarily driven by the geographical distribution of income and certain discrete items, including the tax benefits associated with the release of a valuation allowance and share-based payments.

Ireland, the U.K., and many E.U. member states, among others, have enacted legislation to implement the global minimum tax that are consistent with the OECD’s proposed Pillar Two tax regime.

There remains significant uncertainty, however, as to how Ireland’s Pillar Two tax regime and the OECD’s past and potentially future Pillar Two guidance will ultimately apply to the Company.

The Company is currently evaluating the potential impact that this may have on its global effective tax rate, results of operations, cash flows, and financial condition beginning in 2024.

| Revenue | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Reinsurance Solutions | | | | | | 2,481 | | | | | | 2,190 | | | | | | 13 | | | | | | (1) | | | | | | 4 | | | | | | — | | | | | | 10 | | |

| Health Solutions | | | | | | 2,433 | | | | | | 2,224 | | | | | | 9 | | | | | | — | | | | | | — | | | | | | (1) | | | | | | 10 | | |

| Wealth Solutions | | | | | | 1,431 | | | | | | 1,367 | | | | | | 5 | | | | | | — | | | | | | — | | | | | | 1 | | | | | | 4 | | |

| Total revenue | | | | | | $ | 13,376 | | | | | $ | 12,479 | | | | | 7 | | % | | | | — | | % | | | | 2 | | % | | | | (2) | | % | | | | 7 | | % |

| Revenue | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

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

| Accelerating Aon United Program expenses (1) | | | | | | 135 | | | | | | — | | |

| Transaction costs (3) | | | | | | 17 | | | | | | — | | |

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

(2)In the fourth quarter of 2023, Aon recognized actual and anticipated legal settlement expenses in connection with transactions for which capital was arranged by a third party, Vesttoo Ltd. primarily in the form of letters of credit from third party banks that are alleged to have been fraudulent.

Certain actual or anticipated legal settlements expenses totaling $197 million have been recognized in the current period, where certain potentially meaningful amounts may be recoverable in future periods.

(3)In the fourth quarter of 2023, we entered into a definitive agreement to acquire NFP.

As part of the definitive agreement, certain transaction costs were incurred including advisory, legal, accounting, and other professional or consulting fees required to complete the acquisition.

- Operating expenses decreased $1.3 billion, or 13%, to $8.8 billion in 2022 compared to 2021 due primarily to the $1.0 billion payment made in connection with terminating the combination with WTW (the “Termination Fee”) and certain transaction costs incurred related to the termination in the prior year (together, the “Transaction Costs”) and a $373 million favorable impact from foreign currency translation, partially offset by an increase in expense associated with 6% organic revenue growth, investments in long-term growth, and a $58 million charge related to certain legal settlements reached.

- Operating margin increased to 29.4% in 2022 from 17.1% in 2021.

- Cash flows provided by operating activities was $3.2 billion in 2022, an increase of $1.0 billion, or 48%, from $2.2 billion in 2021, primarily due to the Transaction Costs paid in the prior year period, and strong operating income growth, partially offset by higher incentive compensation payments made in the current year following strong performance in 2021.

We view ESG risks as presenting an important opportunity for Aon to work together as one firm to address client needs and improve our impact on ESG matters.

| | | | | | | | | | | | | | | | | | | | | |

U.S. retail brokerage was pressured primarily by Transaction Solutions, which declined due to lower external deal volume.

Results also reflect strong growth globally in the affinity business across both consumer and business solutions, including growth in the travel and events practice and Digital Client Solutions.

The decrease was primarily driven by a 5% unfavorable impact from foreign currency translation and a 2% unfavorable impact from acquisitions, divestitures, and other.

Compensation and benefits decreased $261 million, or 4%, in 2022 compared to 2021.

The decrease was primarily driven by a $22 million decrease in Transaction Costs and a $19 million favorable impact from foreign currency translation.

Depreciation of fixed assets decreased $28 million, or 16%, in 2022 compared to 2021.

The decrease was primarily driven by a $16 million decrease in Transaction Costs.

Amortization and impairment of intangibles decreased $34 million, or 23%, in 2022 compared to 2021.

Other general expenses decreased $964 million, or 43%, in 2022 compared to 2021.

The decrease was primarily driven by a $1.1 billion decrease in Transaction Costs, partially offset by an increase in expense associated with 6% organic revenue growth, including travel and entertainment expense, and a $58 million charge from certain legal settlements reach in 2022.

The increase primarily reflects an increase in total debt.

Income before income taxes was $3.2 billion in 2022, a 63% increase from $1.9 billion in 2021.

The increase was primarily driven by $1.4 billion in Transaction Costs in the prior year period and strong operational performance.

The 2021 tax rate was primarily driven by the impact of the Termination Fee, the U.K. statutory tax rate increase, and the tax benefit of share-based payments.

The U.K. enacted legislation in the second quarter of 2021 which increases the corporate income tax rate from 19% to 25% with effect from April 1, 2023 and the Company remeasured its U.K. deferred tax assets and liabilities accordingly.

| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Reinsurance Solutions | | | | | | 1,997 | | | | | | 1,814 | | | | | | 10 | | | | | | 2 | | | | | | — | | | | | | — | | | | | | 8 | | |

| Health Solutions | | | | | | 2,154 | | | | | | 2,067 | | | | | | 4 | | | | | | 2 | | | | | | — | | | | | | (8) | | | | | | 10 | | |

| Wealth Solutions | | | | | | 1,426 | | | | | | 1,341 | | | | | | 6 | | | | | | 3 | | | | | | — | | | | | | 1 | | | | | | 2 | | |

| Total revenue | | | | | | $ | 12,193 | | | | | $ | 11,066 | | | | | 10 | | % | | | | 2 | | % | | | | — | | % | | | | (1) | | % | | | | 9 | | % |

(1)Currency impact is determined by translating last year’s revenue at this year’s foreign exchange rates.

| | | | | | | 2022 | | | | | | 2021 | | |

| Transaction costs and other charges related to the combination and resulting termination (1) | | | | | | — | | | | | | 1,436 | | |

(1)As part of the terminated combination with WTW, certain transaction costs were incurred by the Company through the third quarter of 2021.

These costs included advisory, legal, accounting, valuation, and other professional or consulting fees related to the combination, including planned divestitures, some of which were terminated, as well as certain compensation expenses and expenses related to further steps on our Aon United operating model as a result of the termination.

Additionally, this includes the $1 billion Termination Fee paid in connection with the termination of the combination.

| Operating income | | | | | | $ | 2,090 | | | | | $ | 1,583 | | | | | $ | 3,673 | |

| Income before income taxes | | | | | | 1,931 | | | | | | 1,459 | | | | | | 3,390 | | |

| Net income | | | | | | 1,308 | | | | | | 1,459 | | | | | | 2,767 | | |

In addition, income tax expense for the year ended December 30, 2021 excludes the impact of remeasuring the net deferred tax liabilities in the U.K. as a result of the corporate income tax rate increase enacted in the second quarter of 2021.

(3)Adjusted Other income (expense) excludes gains from dispositions of $124 million, for the year ended December 31, 2021.

payments on their behalf, and upon the impact of foreign currency movements.

| Money market funds | | | — | | | | | | 452 | | | | | | 2,871 | | | | | | 3,323 | | |

| Total | | | $ | 690 | | | | | $ | 452 | | | | | $ | 15,900 | | | | | $ | 17,042 | |

In November 2021, the Company’s $500 million 2.20% Senior Notes due November 2022 were classified as Short-term debt and current portion of long-term debt in the Consolidated Statements of Financial Position as the date of maturity is in less than one year as of December 31, 2021.

At December 31, [removed: 2022,] [added: 2023,] we have hedged approximately 45% of our U.K. subsidiaries’ expected exposures to the U.S. dollar, euro, and Japanese yen transactions for the years ending December 31, [removed: 2023] [added: 2024] and [removed: 2024.][added: 2025.]

The potential loss in future earnings from foreign exchange derivative instruments resulting from a hypothetical 10% adverse change in year-end exchange rates would be [removed: $19] [added: $28] million and [removed: $9] [added: $18] million at December 31, [removed: 2023] [added: 2024] and [removed: 2024,] [added: 2025,] respectively.

If we were to translate prior year results at current year exchange rates, diluted earnings per share would have an unfavorable [removed: $0.33] [added: $0.17] impact during the year ended December 31, [removed: 2022.][added: 2023.]

[removed: Further, adjusted diluted earnings per share, a] non-GAAP measure as defined and reconciled under the caption “Review of Consolidated Results — Adjusted Diluted Earnings Per Share,” would have an unfavorable [removed: $0.44] [added: $0.17] impact during the year ended December 31, [removed: 2022] [added: 2023] if we were to translate prior year results at current [removed: quarter] [added: year] exchange rates.

A hypothetical, instantaneous parallel decrease in the year-end yield curve of 100 BPS would cause a decrease, net of derivative positions, of [removed: $67] [added: $69] million to each of [removed: 2023 and] 2024 [added: and 2025] pretax income.

A corresponding increase in the year-end yield curve of 100 BPS would cause an increase, net of derivative positions, of [removed: $67] [added: $69] million to each of [removed: 2023 and] 2024 [added: and 2025] pre-tax income.

We have long-term debt outstanding, excluding the current portion, with a fair market value of [removed: $8.7] [added: $9.2] billion and [removed: $9.2] [added: $8.7] billion as of December 31, [removed: 2022] [added: 2023] and December 31, [removed: 2021,] [added: 2022,] respectively.

The fair value was [removed: less] [added: greater] than the carrying value by [removed: $1.1] [added: $0.8] billion at December 31, [removed: 2022,] [added: 2023,] and [removed: $0.9] [added: $1.1] billion [removed: greater] [added: less] than the carrying value at December 31, [removed: 2021.][added: 2022.]

A hypothetical 1% increase or decrease in interest rates would change the fair value by a decrease of 7% or an increase of 8%, respectively, at December 31, [removed: 2022.][added: 2023.]

Further, adjusted diluted earnings per share, a

Aon plc (which may be referred to as “Aon,” the “Company,” “we,” “us,” or “our”) is a leading global professional services firm providing a broad range of [removed: risk, health,] [added: risk] and [removed: wealth] [added: human capital] solutions.

Through our experience, global reach, and comprehensive analytics, we [removed: are better able to] help clients meet rapidly changing, increasingly complex, and interconnected [removed: challenges.][added: challenges related to risk and people.]

We are committed to accelerating innovation to address unmet and evolving client [removed: needs,] [added: needs] so that our clients are better informed, better advised, and able to make better decisions to protect and grow their business.

Management [removed: is] [added: 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.

[removed: The Company operates] [added: We operate] as one segment that includes all of [removed: Aon’s] [added: our] continuing operations, which, as a global professional services firm, provides [removed: advice] [added: a broad range of risk] and [added: human capital] solutions [removed: to clients focused on risk, health and wealth] through four [added: solution lines — Commercial risk, Reinsurance, Health, and Wealth, which make up our] principal products and [removed: services: Commercial Risk Solutions, Reinsurance Solutions, Health Solutions, and Wealth Solutions.][added: services.]

In [removed: 2022,] [added: 2023,] our consolidated total revenue was [removed: $12,479] [added: $13,376] million.

This includes [removed: $6,715] [added: $7,043] million in Commercial Risk Solutions, [removed: $2,190] [added: $2,481] million in Reinsurance Solutions, [removed: $2,224] [added: $2,433] million in Health Solutions, and [removed: $1,367] [added: $1,431] million in Wealth Solutions, before certain intercompany eliminations.

Capital markets is a global investment bank with expertise in insurance-linked securities, [added: capital raising, strategic advice, restructuring, and mergers and acquisitions.]

*Health Solutions* includes consulting and brokerage, consumer benefits solutions, and [removed: human capital solutions.][added: talent.]

Our [removed: human capital] [added: 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, [removed: human capital] [added: talent] integration in transaction situations, Corporate Governance, ESG consulting, and strategic employee communication.

[added: 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, [added: human resources,] and financial services firms.

No one client accounted for more than 2% of our consolidated total revenues in [removed: 2022.][added: 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 [removed: 2022.][added: 2023.]

Our culture is driven by our values – committed as one firm to our purpose, united through trust [added: and integrity] as one inclusive, diverse team, and passionate about making our colleagues and clients successful.

Our colleagues are the cornerstone of [removed: Aon's] [added: our] success.

Our Aon United strategy defines how [removed: Aon] [added: our] colleagues work together to deliver value to clients, setting a new standard for client leadership.

Aon United is brought to life through our common client value creation model which scales strategies from across [added: the firm to bring the best of Aon to clients.]

As of December 31, [removed: 2022,] [added: 2023,] we employed approximately 50,000 employees and conducted our operations in more than 120 countries and sovereignties.

Our Inclusive People Leadership strategy is a central part of our Aon United [removed: Blueprint] [added: strategy] and is a key enabler to realizing our aspirations and purpose as a firm.

[removed: At Aon, all] [added: All our] colleagues are called upon to be leaders in embracing and [removed: modelling] [added: modeling] our Aon United values and behaviors.

Inclusive People Leadership at Aon [removed: ensures] [added: is designed to ensure] that all colleagues – at every stage of their career journey – are equipped and motivated to deliver on our purpose and able to achieve their full potential.

[removed: The aim of] [added: Colleagues benefit from our] Smart Working [removed: is] [added: approach, which aims] to create a healthy, productive, inclusive, and sustainable way of working, enabling colleagues to deliver their best work for clients from wherever they are best placed to do so.

Colleagues are invited to complete a [removed: variety] [added: broad spectrum] of curricula to meet their career stage goals and developmental needs.

From self-guided learning courses to advanced leadership programs, the curriculum is aligned to the Aon United [removed: Blueprint] [added: strategy] and Inclusive People Leader strategy.

[removed: Aon’s] [added: Our] investment in technology and use of virtual [added: and in-person] based learning and development programs allows us to deliver targeted offerings designed to advance all colleagues’ development.

Providing an engaging and rewarding colleague experience is a top priority for [removed: our firm] [added: us] and understanding colleagues’ feedback helps us [added: to] reach that goal.

Business Resource Groups are our independent, voluntary, non-profit associations that provide input, take action, and help identify opportunities for our firm to further commitments to [removed: I&D] [added: Inclusion] and [added: Diversity (I&D) and] belonging.

The pulse surveys for [removed: 2022] [added: 2023] were focused on topics such as manager and leadership support, delivering on our Aon Story, colleague wellbeing, I&D, talent acquisition and performance [removed: &] [added: and] rewards.

[removed: Aon’s feedback] [added: Feedback] from our workforce provides management [added: with] a better understanding of evolving colleague viewpoints, and ensures we are taking appropriate steps to drive colleague engagement and retention.

Our compensation [removed: programs,] [added: programs -] including salary, recognition, cash, and equity [removed: incentives,] [added: incentives -] are connected to our formal performance management, and career development approach.

Beginning in 2021, 20% of the short-term incentives for senior executives are based on quantifiable performance against firm-wide [removed: I&D] [added: inclusion] initiatives.

We believe that inclusive and diverse teams produce better insight, better [removed: solutions, and ultimately] [added: solutions and, ultimately,] the best outcomes for clients and [removed: Aon’s] [added: our] long-term success.

We achieve this by aligning [removed: I&D] [added: inclusion] actions to the following pillars: Recruitment, Education, Promotion, and Representation.

Our commitment to [removed: I&D] [added: inclusion] starts from the top with our Board of Directors, including its [removed: I&D] [added: Inclusion & Wellbeing] Sub-Committee.

As of December 31, [removed: 2022, Aon’s] [added: 2023, our] global workforce was 54% women and 46% men, and the Aon Executive [removed: Committee] [added: Committee,] which leads the firm was [removed: 48%] [added: 58%] women and [removed: 52%] [added: 42%] men.

New colleague hires for the year were [removed: 51%] [added: 53%] women and [removed: 49%] [added: 47%] men.

[removed: Aon’s] [added: Our] U.S. workforce was 25% racially or ethnically diverse, calculated as a percentage of colleagues that have voluntarily disclosed their race or ethnicity to Aon.

At the manager level, [removed: 13%] [added: 11%] of U.S. senior leaders and 18% of U.S. managers with one or more direct report were racially or ethnically diverse.

New colleague hires for the year in the U.S. were [removed: 31%] [added: 34%] racially or ethnically diverse.

On December 19, 2023, Aon entered into a definitive agreement (the “Merger Agreement”) with Randolph Acquisition Corp., a Delaware corporation and an indirect, wholly owned subsidiary of Aon (the “Acquirer”), Randolph Merger Sub LLC, a Delaware limited liability company and a direct, wholly owned subsidiary of the Acquirer, NFP Intermediate Holdings A Corp., a Delaware corporation (“NFP”), and NFP Parent Co, LLC, a Delaware limited liability company (the “NFP Seller”), pursuant to which the Acquirer will acquire NFP for an aggregate purchase price of approximately $7 billion in cash and approximately 20,000,000 class A ordinary shares, nominal value of $0.01, in capital of Aon, in each case, subject to certain adjustments as set forth in the Merger Agreement (the “Transaction”).

The Company expects to fund the cash portion of the consideration with approximately $7 billion of new debt, with $5 billion raised in advance of the closing date and $2 billion raised at close of the acquisition.

The acquisition is expected to be completed by mid-2024, subject to satisfaction or waiver of the closing conditions set forth in the Merger Agreement, including applicable regulatory approval.

The CODM assesses the performance of the Company and allocates resources based on one segment: Aon United.

In 2023, we announced our 3x3 Plan to go further, faster and continue evolving with our clients and build the capability to deliver the full value of our firm over the next three years.

*Inclusion*

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 Aon Growth Ventures Group.

capital raising, strategic advice, restructuring, and mergers and acquisitions.

Additionally, we compete with

the firm to bring the best of Aon to clients.

Colleagues benefit from our “Smart Working” approach.

Eligible colleagues that were active on September 24, 2021 received a one-time stock based award enabling Aon colleagues to share in the future success of our Aon United mission.

*Inclusion and Diversity*

We hereby incorporate by reference Note [removed: 15] [added: 16] “Claims, Lawsuits, and Other Contingencies” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report.

| FOR THE FISCAL YEAR ENDED | | | | | | | | | DECEMBER 31, [removed: 2022] [added: 2023] | | |

[added: |] Metropolitan Building, James Joyce Street, Dublin 1, [removed: Ireland D01] [added: Ireland | | | | | | D01] K0Y8 [added: | | |]

[added: |] (Address of principal executive offices) [added: | | | | | |] (Zip Code) [added: | | |]

| Guarantees of Aon [added: Corporation and Aon Global Holdings] plc’s [removed: 4.00%] [added: 5.35%] Senior Notes due [removed: 2023] [added: 2033] | | | | | | [removed: AON23] [added: AON33] | | | | | | New York Stock Exchange | | |

As of June 30, [removed: 2022,] [added: 2023,] the aggregate market value of the registrant’s Class A Ordinary Shares held by non-affiliates of the registrant was [removed: $57,066,496,679] [added: $70,135,237,097] based on the closing sales price as reported on the New York Stock Exchange — Composite Transaction Listing.

Number of the registrant’s Class A Ordinary Shares of Aon plc, $0.01 nominal value, outstanding as of February [removed: 16, 2023: 205,142,379.][added: 15, 2024: 198,297,735.]

Portions of the registrant’s proxy statement for its [removed: 2023] [added: 2024] Annual General Meeting of Shareholders are incorporated by reference in this report in response to Part III, Items 10, 11, 12, 13, and 14.

This report contains certain statements related to future results, or states our intentions, beliefs, and expectations or predictions for the future, all of which are forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of [removed: 1995.][added: 1995, Section 27A of the Securities Act of 1933, as amended, (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).]

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 [removed: initiatives;] [added: initiatives, including] the [added: impacts of the Accelerating Aon United Program; the pending acquisition of NFP; the] outcome of contingencies; dividend policy; the expected impact of acquisitions, dispositions, and other significant transactions or the termination thereof; litigation and regulatory matters; pension obligations; cash flow and liquidity; expected effective tax rate; expected foreign currency translation impacts; potential changes in laws or future actions by regulators; and the impact of changes in accounting rules.

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

- limits on our subsidiaries’ ability to pay dividends or otherwise make payments to [removed: us;][added: their respective parent entities;]

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

- the failure to retain, attract and develop experienced and qualified [removed: personnel;][added: personnel, whether as a result of the pending acquisition of NFP or otherwise;]

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

- the effects of natural or man-made disasters, including the effects of [removed: the COVID-19 pandemic and other] health pandemics and the impacts of [removed: climate change;][added: climate-related events;]

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

- our ability to develop and implement innovative growth strategies and initiatives intended to yield cost [removed: savings,] [added: savings (including the Accelerating Aon United Program)] and the ability to achieve such growth or cost savings; [removed: and]

- the effects of Irish law on our operating flexibility and the enforcement of judgments against [removed: us.][added: us;]

| | | | [Item 1. [removed: Business](#i59e793ae01c14397a5ef8c35747c25dd_19)] [added: Business](#i3f61d50494c24ddfa62e11443848764c_19)] | | |

| | | | [Item 1A. Risk [removed: Factors](#i59e793ae01c14397a5ef8c35747c25dd_22)] [added: Factors](#i3f61d50494c24ddfa62e11443848764c_22)] | | |

| | | | [Item 1B. Unresolved Staff [removed: Comments](#i59e793ae01c14397a5ef8c35747c25dd_25)] [added: Comments](#i3f61d50494c24ddfa62e11443848764c_25)] | | |

| | | | [Item 2. [removed: Properties](#i59e793ae01c14397a5ef8c35747c25dd_28)] [added: Properties](#i3f61d50494c24ddfa62e11443848764c_28)] | | |

| | | | [Item 3. Legal [removed: Proceedings](#i59e793ae01c14397a5ef8c35747c25dd_31)] [added: Proceedings](#i3f61d50494c24ddfa62e11443848764c_31)] | | |

| | | | [Item 4. Mine Safety [removed: Disclosure](#i59e793ae01c14397a5ef8c35747c25dd_34)] [added: Disclosure](#i3f61d50494c24ddfa62e11443848764c_34)] | | |

| | | | [Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity [removed: Securities](#i59e793ae01c14397a5ef8c35747c25dd_43)] [added: Securities](#i3f61d50494c24ddfa62e11443848764c_43)] | | |

| | | | [Item 7. Management's Discussion and Analysis of Financial Condition and Results of [removed: Operations](#i59e793ae01c14397a5ef8c35747c25dd_49)] [added: Operations](#i3f61d50494c24ddfa62e11443848764c_49)] | | |

| | | | [Item 7A. Quantitative and Qualitative Disclosures About Market [removed: Risk](#i59e793ae01c14397a5ef8c35747c25dd_67)] [added: Risk](#i3f61d50494c24ddfa62e11443848764c_67)] | | |

| | | | [Item 8. Financial Statements and Supplementary [removed: Data](#i59e793ae01c14397a5ef8c35747c25dd_70)] [added: Data](#i3f61d50494c24ddfa62e11443848764c_70)] | | |

| | | | [Aon plc Consolidated Statements of [removed: Income](#i59e793ae01c14397a5ef8c35747c25dd_73)] [added: Income](#i3f61d50494c24ddfa62e11443848764c_73)] | | |

| | | | [Aon plc Consolidated Statements of Comprehensive [removed: Income](#i59e793ae01c14397a5ef8c35747c25dd_76)] [added: Income](#i3f61d50494c24ddfa62e11443848764c_76)] | | |

| | | | [Aon plc Consolidated Statements of Financial [removed: Position](#i59e793ae01c14397a5ef8c35747c25dd_82)] [added: Position](#i3f61d50494c24ddfa62e11443848764c_79)] | | |

| | | | [removed: Aon] [added: [Aon] plc Consolidated Statements of Shareholders' [removed: Equity] [added: Equity](#i3f61d50494c24ddfa62e11443848764c_82)] | | |

| | | | [Aon plc Consolidated Statements of Cash [removed: Flows](#i59e793ae01c14397a5ef8c35747c25dd_85)] [added: Flows](#i3f61d50494c24ddfa62e11443848764c_85)] | | |

| | | | [Notes to Consolidated Financial [removed: Statements](#i59e793ae01c14397a5ef8c35747c25dd_88)] [added: Statements](#i3f61d50494c24ddfa62e11443848764c_88)] | | |

| | | | [Item 9. Changes in and Disagreements with Accountants on Accounting and Financial [removed: Disclosure](#i59e793ae01c14397a5ef8c35747c25dd_145)] [added: Disclosure](#i3f61d50494c24ddfa62e11443848764c_142)] | | |

| | | | [Item 9A. Controls and [removed: Procedures](#i59e793ae01c14397a5ef8c35747c25dd_148)] [added: Procedures](#i3f61d50494c24ddfa62e11443848764c_145)] | | |

| | | | [Item 9B. Other [removed: Information](#i59e793ae01c14397a5ef8c35747c25dd_151)] [added: Information](#i3f61d50494c24ddfa62e11443848764c_148)] | | |

| | | | [Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevents [removed: Inspections](#i59e793ae01c14397a5ef8c35747c25dd_154)] [added: Inspections](#i3f61d50494c24ddfa62e11443848764c_151)] | | |

| | | | [Item 10. Directors, Executive Officers and Corporate [removed: Governance](#i59e793ae01c14397a5ef8c35747c25dd_160)] [added: Governance](#i3f61d50494c24ddfa62e11443848764c_157)] | | |

| | | | [Item 11. Executive [removed: Compensation](#i59e793ae01c14397a5ef8c35747c25dd_163)] [added: Compensation](#i3f61d50494c24ddfa62e11443848764c_160)] | | |

| | | | | | | | | |

| --- | --- | --- | --- | --- | --- | --- | --- | --- |

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).

These statements include statements about our plans, objectives, strategies, financial performance and outlook, trends, prospects or other future events and involve known and unknown risks that are difficult to predict.

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

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

- potential impact of the consummation of the pending acquisition of NFP on relationships, including with suppliers, customers, employees and regulators.

| [PART I](#i3f61d50494c24ddfa62e11443848764c_16) | | | | | |

| | | | [Item 1C. Cybersecurity](#i3f61d50494c24ddfa62e11443848764c_1464) | | |

| [PART II](#i3f61d50494c24ddfa62e11443848764c_40) | | | | | |

| | | | [Item 6. \[Reserved\]](#i3f61d50494c24ddfa62e11443848764c_46) | | |

| [PART III](#i3f61d50494c24ddfa62e11443848764c_154) | | | | | |

| [PART IV](#i3f61d50494c24ddfa62e11443848764c_172) | | | | | |

| [SIGNATURES](#i3f61d50494c24ddfa62e11443848764c_181) | | | | | |

| AAU | | | Accelerating Aon United Program | | |

| | | | | | |

| | | | | | |

| CIGC | | | Cyber Incident Governance Committee | | |

| CPO | | | Chief Privacy Officer | | |

| CSO | | | Chief Security Officer | | |

| | | | | | |

| ERM | | | Enterprise risk management | | |

| | | | | | |

| GEOC | | | Global Emergency Operations Center | | |

| | | | | | |

| GPO | | | Global Privacy Office | | |

| GSS | | | Global Security Services | | |

| NFP | | | National Financial Partners | | |

| | | | | | |

| | | | | | |

| NIST | | | National Institute of Standards and Technology | | |

| | | | | | |

| | | | | | |

| SOFR | | | Secured Overnight Financing Rate | | |

| | | | | | |

| [PART I](#i59e793ae01c14397a5ef8c35747c25dd_16) | | | | | |

| [PART II](#i59e793ae01c14397a5ef8c35747c25dd_40) | | | | | |

| | | | [Item 6. \[Reserve\]](#i59e793ae01c14397a5ef8c35747c25dd_46) | | |

| [PART III](#i59e793ae01c14397a5ef8c35747c25dd_157) | | | | | |

| [PART IV](#i59e793ae01c14397a5ef8c35747c25dd_175) | | | | | |

| [SIGNATURES](#i59e793ae01c14397a5ef8c35747c25dd_184) | | | | | |

| ASC | | | Accounting Standards Codification | | |

| CCC | | | Christchurch City Council | | |

| FASB | | | Financial Accounting Standards Board | | |

| NEBC | | | National Employee Benefits Committee | | |

| WTW | | | Willis Towers Watson Public Limited Company | | |

Aon has from time-to-time experienced cybersecurity incidents.

In the event of a cybersecurity incident, Aon responds in accordance with our policies, processes, applicable laws and regulations.

When necessary, Aon also engages third parties, such as external cybersecurity advisors to investigate and remediate incidents.

To date, the cybersecurity incidents have not had a material impact on our business strategy, results of operations, or financial condition.

For additional information regarding the risks from cybersecurity threats, please see the risk factors entitled “*We rely on complex information technology systems and networks to operate our business.

Any significant system or network disruption due to a breach in the security of our information technology systems could have a negative impact on our reputation, operations, sales and operating results*” and “*Improper disclosure of confidential, personal, or proprietary data could result in regulatory scrutiny, legal liability, or harm to our reputation*” in Part I, Item 1A of this report.

Aon strives to protect the personal and confidential data of our clients and our colleagues.

To do so, Aon engages in a risk-based approach to adopting and implementing technical, organizational, administrative, and physical safeguards for cybersecurity.

One key component to safeguard against risks facing Aon’s technology and security is Aon’s enterprise risk management (“ERM”) program.

Aon’s management carries out the processes, controls, and practices of the Company’s ERM program, including the identification, assessment, prioritization, and mitigation of cybersecurity risks.

The Company’s Board of Directors (“Board”) oversees Aon’s ERM program and allocates certain oversight responsibilities to its committees and any sub-committees, as appropriate.

The Board has delegated to the Audit Committee the primary responsibility for the oversight of the Company’s ERM program.

The Audit Committee also has primary responsibility for the oversight of cybersecurity risk and engages in regular discussion with management regarding cybersecurity and privacy risk mitigation and incident management.

Cybersecurity matters are an important focus of our Board’s oversight of risk.

The Company’s management, including the Chief Security Officer (“CSO”), regularly presents to the Audit Committee of the Board regarding cybersecurity matters.

In addition, members of senior management attend Board and committee meetings to address any questions or concerns raised by the Board related to risk management, including relating to cybersecurity, and any other matters.

In addition, Aon maintains a Global Security Services (“GSS”) organization, led by the CSO, with dedicated security personnel responsible for protecting Aon’s people, property and information.

Aon’s CSO reports to Aon’s Chief Operating Officer and is an experienced technology and cybersecurity professional, with over 20 years’ experience in information security and technology.

The Company’s Global Emergency Operations Center (“GEOC”) serves as a single point of control, coordination, and communication for protecting Aon's people, property, and information.

The GEOC is responsible for triage of all incidents pertaining to the confidentiality, integrity, and availability of customer data.

The GEOC monitors threat intelligence reporting and receives alerts and reports from Aon colleagues and IT systems.

In coordination with the Global Privacy Office (“GPO”) and GSS, the GEOC reports significant cybersecurity incidents to the Cyber Incident Governance Committee (“CIGC”).

The CIGC is comprised of members of management, and is responsible for reviewing significant cybersecurity incidents.

The CIGC includes the CSO, the Chief Privacy Officer (“CPO”), and other representatives from the Company’s GPO and GSS, as well as leaders from the Company’s operations, risk management, law & compliance, controllership, internal audit, and communications functions.

The CIGC reviews and assesses cybersecurity incidents and is responsible for coordinating the mitigation and remediation of such incidents.

The Company regularly conducts security scanning and reviews of regulatory IT controls (including Sarbanes Oxley).

Additional security reviews may be triggered in connection with the assessment of new projects, business initiatives or third-party/supplier engagements.

The Company’s Internal Audit function follows a risk-based approach to evaluating controls over key enterprise risks, including cybersecurity, as well as compliance with select regulations and corporate policies.

Aon has established a third-party risk governance program that creates guidelines for selecting and managing its suppliers, including assessing of their operational capabilities, adherence to the Company’s data security requirements, and technical, organizational, and physical safeguards.

Contractual requirements and periodic reviews are designed to promote compliance with Aon’s security requirements.

Aon’s GPO and Law & Compliance Department work with business units to incorporate appropriate controls into supplier contracts.

The Company’s controls align to the National Institute of Standards and Technology (“NIST”) Framework.

This does not imply that we meet technical specifications or requirements at all times but that the aforementioned frameworks help us identify, assess, and manage cybersecurity risks relevant to our business.

We use the aforementioned risk-based approach to cybersecurity to promote accountability for all of our functions across our businesses as well as our third parties to monitor for and prevent any adverse consequences from cybersecurity risks.

These risks are continuously evolving, and our program is designed to evaluate these risks on an ongoing basis.

| 200 E. Randolph Street, Chicago, Illinois | | | 312,000 | | | | | | [removed: 2028] [added: 2030] | | |

[added: 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, [removed: 2022.][added: 2023.]

See Note 8 “Lease Commitments” of the Notes

The executive officers of Aon, as of February [removed: 17, 2023] [added: 16, 2024] 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.

| Eric Andersen | | | | | | [removed: 58] [added: 59] | | | | | | 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. Mr. Andersen was appointed Co-President of the Company in May 2018 and became President in February 2020. He was named an Executive Officer in February 2017. | | |

| Gregory C. Case | | | | | | [removed: 60] [added: 61] | | | | | | 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 | | | | | | [removed: 51] [added: 52] | | | | | | 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. | | |

| Michael Neller | | | | | | [removed: 44] [added: 45] | | | | | | 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. | | |

| Mindy Simon | | | | | | [removed: 46] [added: 47] | | | | | | Chief Operating Officer. Ms. Simon joined Aon as Chief Operating Officer in October 2022. Prior to joining Aon, Ms. Simon served as Chief Information Officer for Conagra Brands since June 2017. Prior to her role as Chief Information Officer, Ms. Simon held a variety of roles in finance and information technology with Conagra Brands since joining the company in 2000, including serving as VP Global Business Services from January 2016 to June 2017, and VP Information Technology from 2008 to 2016. | | |

| Jillian Slyfield | | | | | | [removed: 49] [added: 50] | | | | | | Chief Innovation Officer. Ms. Slyfield joined Aon in November 2015 as an Account Executive and later served as the Resident Sales Director for San Francisco until her appointment to Managing Director, Digital Economy Practice Leader in 2018. Ms. Slyfield was appointed Chief Innovation Officer of Aon in December 2021. Prior to joining Aon in 2015, Ms. Slyfield held client executive and commercial insurance executive positions at Marsh and Wells Fargo Insurance Services. | | |

| Lisa Stevens | | | | | | [removed: 52] [added: 53] | | | | | | Chief People Officer and Head of Global Human Capital Solutions. 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 | | | | | | [removed: 46] [added: 47] | | | | | | 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 | | | | | | [removed: 51] [added: 52] | | | | | | 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. | | |

On February [removed: 16, 2023,] [added: 15, 2024,] the last reported sale price of our ordinary shares as reported by the NYSE was [removed: $310.25] [added: $314.37] per share.

We have approximately [removed: 409] [added: 392] holders of record of our class A ordinary shares as of February 16, [removed: 2023.][added: 2024.]

We did not make any unregistered sales of equity in [removed: 2022.][added: 2023.]

In February 2024, Aon paid a quarterly cash dividend of $0.615 per share.

The declaration of future cash dividends is at the discretion of our Board of Directors and will depend upon our future earnings, liquidity, cash flows, capital allocation, financial conditions, and other factors.

| 10/1/23 – 10/31/23 | | | | | | 811,155 | | | | | | $ | 320.98 | | | | | 811,155 | | | | | | $ | 3,806,897,048 | |

| 11/1/23 – 11/30/23 | | | | | | 858,950 | | | | | | $ | 327.18 | | | | | 858,950 | | | | | | $ | 3,525,862,650 | |

| 12/1/23 – 12/31/23 | | | | | | 660,279 | | | | | | $ | 315.92 | | | | | 660,279 | | | | | | $ | 3,317,269,632 | |

| | | | | | | 2,330,384 | | | | | | $ | 321.83 | | | | | 2,330,384 | | | | | | $ | 3,317,269,632 | |

| 10/1/22 – 10/31/22 | | | | | | 896,708 | | | | | | $ | 278.80 | | | | | 896,708 | | | | | | $ | 6,442,274,888 | |

| 11/1/22 – 11/30/22 | | | | | | 660,458 | | | | | | $ | 296.76 | | | | | 660,458 | | | | | | $ | 6,246,278,509 | |

| 12/1/22 – 12/31/22 | | | | | | 753,523 | | | | | | $ | 303.90 | | | | | 753,523 | | | | | | $ | 6,017,286,196 | |

| | | | | | | 2,310,689 | | | | | | $ | 292.12 | | | | | 2,310,689 | | | | | | $ | 6,017,286,196 | |

We have audited the accompanying consolidated statements of financial position of Aon plc (the Company) as of December 31, [removed: 2022] [added: 2023] and [removed: 2021,] [added: 2022,] the related consolidated statements of income, comprehensive income, shareholders’ equity (deficit) and cash flows for each of the three years in the period ended December 31, [removed: 2022,] [added: 2023,] and the related notes (collectively referred to as the “consolidated financial statements”).

In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, [removed: 2022] [added: 2023] and [removed: 2021,] [added: 2022,] and the results of its operations and its cash flows for each of the three years in the period ended December 31, [removed: 2022,] [added: 2023,] in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, [removed: 2022,] [added: 2023,] based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February [removed: 17, 2023,] [added: 16, 2024,] expressed an unqualified opinion thereon.

| *Description of the Matter* | | | As discussed in Note [removed: 9] [added: 10] “Income Taxes” of the Notes to Consolidated Financial Statements, the Company had net deferred tax assets of [removed: $725] [added: $1,080] million at December 31, [removed: 2022.] [added: 2023.] Deferred tax assets are reduced by a valuation allowance if, based on the weight of all available evidence, in management’s judgment it is more likely than not that some portion, or all, of the deferred tax assets will not be realized. Conclusions on the realizability of certain net deferred tax assets involve significant management judgement including assumptions and estimates related to the amount, timing, and jurisdiction of future taxable income. Auditing the [added: net] deferred tax asset calculation and the related [removed: forecast] [added: projection] of future taxable income was especially challenging as it involved a high degree of auditor judgement around management’s assumptions and estimates of future taxable income. | | | | | | | | | | | |

| *How We Addressed the Matter in Our Audit* | | | We obtained an understanding, evaluated the design and operating effectiveness of internal controls that address the risks of material misstatement relating to the realizability of deferred tax assets, including controls over management’s projections of the amount, timing, and jurisdiction of future taxable [removed: income and the related assumptions.] [added: income.] Among other audit procedures performed, we evaluated the assumptions used by the Company to develop projections of future taxable income by income tax jurisdiction and tested the completeness and accuracy of the underlying data used in the projections. [removed: For example, we inspected the assumptions made in the calculation of future taxable income, including the growth rate, the estimates of the reversal of cumulative temporary differences, and the capital and debt requirements by jurisdiction.] We compared the projections of future taxable income with the actual results of prior periods. Further, we involved tax subject matter professionals in the review of the information identified. | | | | | | | | | | | |

[removed: ][added: ]

| (millions, except per share data) | | | | | | [removed: 2022] [added: 2023] | | | | | | [removed: 2021] [added: 2022] | | | | | | [removed: 2020] [added: 2021] | | |

| Total revenue | | | | | | $ | [removed: 12,479] [added: 13,376] | | | | | $ | [removed: 12,193] [added: 12,479] | | | | | $ | [removed: 11,066] [added: 12,193] | |

| Compensation and benefits | | | | | | [removed: 6,477] [added: 6,902] | | | | | | [removed: 6,738] [added: 6,477] | | | | | | [removed: 5,905] [added: 6,738] | | |

| Information technology | | | | | | [removed: 509] [added: 534] | | | | | | [removed: 477] [added: 509] | | | | | | [removed: 444] [added: 477] | | |

| Premises | | | | | | [removed: 289] [added: 294] | | | | | | [removed: 327] [added: 289] | | | | | | [removed: 291] [added: 327] | | |

| Depreciation of fixed assets | | | | | | [removed: 151] [added: 167] | | | | | | [removed: 179] [added: 151] | | | | | | [removed: 167] [added: 179] | | |

| Amortization and impairment of intangible assets | | | | | | [removed: 113] [added: 89] | | | | | | [removed: 147] [added: 113] | | | | | | [removed: 246] [added: 147] | | |

| Other general expense | | | | | | [removed: 1,271] [added: 1,470] | | | | | | [removed: 2,235] [added: 1,271] | | | | | | [removed: 1,232] [added: 2,235] | | |

| Total operating expenses | | | | | | [removed: 8,810] [added: 9,591] | | | | | | [removed: 10,103] [added: 8,810] | | | | | | [removed: 8,285] [added: 10,103] | | |

| Operating income | | | | | | [removed: 3,669] [added: 3,785] | | | | | | [removed: 2,090] [added: 3,669] | | | | | | [removed: 2,781] [added: 2,090] | | |

| Interest income | | | | | | [removed: 18] [added: 31] | | | | | | [removed: 11] [added: 18] | | | | | | [removed: 6] [added: 11] | | |

| Interest expense | | | | | | [removed: (406)] [added: (484)] | | | | | | [removed: (322)] [added: (406)] | | | | | | [removed: (334)] [added: (322)] | | |

| Other income (expense) | | | | | | [removed: (125)] [added: (163)] | | | | | | [removed: 152] [added: (125)] | | | | | | [removed: 13] [added: 152] | | |

| Income before income taxes | | | | | | [removed: 3,156] [added: 3,169] | | | | | | [removed: 1,931] [added: 3,156] | | | | | | [removed: 2,466] [added: 1,931] | | |

| Income tax expense | | | | | | [removed: 510] [added: 541] | | | | | | [removed: 623] [added: 510] | | | | | | [removed: 448] [added: 623] | | |

| Net income | | | | | | [removed: 2,646] [added: 2,628] | | | | | | [removed: 1,308] [added: 2,646] | | | | | | [removed: 2,018] [added: 1,308] | | |

| Less: Net income attributable to noncontrolling interests | | | | | | [removed: 57] [added: 64] | | | | | | [removed: 53] [added: 57] | | | | | | [removed: 49] [added: 53] | | |

| Net income attributable to Aon shareholders | | | | | | $ | [removed: 2,589] [added: 2,564] | | | | | $ | [removed: 1,255] [added: 2,589] | | | | | $ | [removed: 1,969] [added: 1,255] | |

| Basic net income per share attributable to Aon shareholders | | | | | | $ | [removed: 12.23] [added: 12.60] | | | | | $ | [removed: 5.59] [added: 12.23] | | | | | $ | [removed: 8.49] [added: 5.59] | |

| Diluted net income per share attributable to Aon shareholders | | | | | | $ | [removed: 12.14] [added: 12.51] | | | | | $ | [removed: 5.55] [added: 12.14] | | | | | $ | [removed: 8.45] [added: 5.55] | |

| Weighted average ordinary shares outstanding - basic | | | | | | [removed: 211.7] [added: 203.5] | | | | | | [removed: 224.7] [added: 211.7] | | | | | | [removed: 231.9] [added: 224.7] | | |

| Weighted average ordinary shares outstanding - diluted | | | | | | [removed: 213.2] [added: 205.0] | | | | | | [removed: 226.1] [added: 213.2] | | | | | | [removed: 233.1] [added: 226.1] | | |

| (millions) | | | | | | [removed: 2022] [added: 2023] | | | | | | [removed: 2021] [added: 2022] | | | | | | [removed: 2020] [added: 2021] | | |

| Net income | | | | | | $ | [removed: 2,646] [added: 2,628] | | | | | $ | [removed: 1,308] [added: 2,646] | | | | | $ | [removed: 2,018] [added: 1,308] | |

| Net income attributable to Aon shareholders | | | | | | [removed: 2,589] [added: 2,564] | | | | | | [removed: 1,255] [added: 2,589] | | | | | | [removed: 1,969] [added: 1,255] | | |

| Change in fair value of financial instruments | | | | | | [removed: (13)] [added: 13] | | | | | | [removed: 1] [added: (13)] | | | | | | [removed: 13] [added: 1] | | |

| Foreign currency translation adjustments | | | | | | [removed: (528)] [added: 276] | | | | | | [removed: (289)] [added: (528)] | | | | | | [removed: 263] [added: (289)] | | |

| Postretirement benefit obligation | | | | | | [removed: (211)] [added: (40)] | | | | | | [removed: 277] [added: (211)] | | | | | | [removed: (101)] [added: 277] | | |

| Total other comprehensive income (loss) | | | | | | [removed: (752)] [added: 249] | | | | | | [removed: (11)] [added: (752)] | | | | | | [removed: 175] [added: (11)] | | |

| Less: Other comprehensive [removed: income (loss)] [added: loss] attributable to noncontrolling interests | | | | | | [removed: —] [added: (1)] | | | | | | [removed: (1)] [added: —] | | | | | | [removed: 3] [added: (1)] | | |

| Total other comprehensive income (loss) attributable to Aon shareholders | | | | | | [removed: (752)] [added: 250] | | | | | | [removed: (10)] [added: (752)] | | | | | | [removed: 172] [added: (10)] | | |

| Comprehensive income attributable to Aon shareholders | | | | | | $ | [removed: 1,837] [added: 2,814] | | | | | $ | [removed: 1,245] [added: 1,837] | | | | | $ | [removed: 2,141] [added: 1,245] | |

| (millions, except nominal value) | | | | | | [removed: 2022] [added: 2023] | | | | | | [removed: 2021] [added: 2022] | | |

| Cash and cash equivalents | | | | | | $ | [added: 778 | | | | | $ |] 690 | | | | | $ | 544 | |

February 16, 2024

| Accelerating Aon United Program expenses | | | | | | 135 | | | | | | — | | | | | | — | | |

| Less: Net income attributable to noncontrolling interests | | | | | | 64 | | | | | | 57 | | | | | | 53 | | |

| Net income | | | | | | — | | | | | | — | | | | | | 2,564 | | | | | | — | | | | | | 64 | | | | | | 2,628 | | |

| Shares repurchased | | | | | | (8.4) | | | | | | — | | | | | | (2,700) | | | | | | — | | | | | | — | | | | | | (2,700) | | |

| Balance at December 31, 2023 | | | | | | 198.6 | | | | | | $ | 6,946 | | | | | $ | (3,399) | | | | | $ | (4,373) | | | | | $ | 84 | | | | | $ | (742) | |

| Depreciation of fixed assets | | | | | | 167 | | | | | | 151 | | | | | | 179 | | |

| Amortization and impairment of intangible assets | | | | | | 89 | | | | | | 113 | | | | | | 147 | | |

| Accelerating Aon United Program liabilities | | | | | | 99 | | | | | | — | | | | | | — | | |

| Cash and cash equivalents and funds held on behalf of clients classified as held for sale | | | | | | 43 | | | | | | — | | | | | | — | | |

The Company recognizes compensation

item at both the inception of the hedge and on an ongoing basis.

Where Aon has provided notice of cancellation pursuant to a lease agreement, the lease is modified with the associated ROU asset and the related lease liability remeasured, which may include any additional termination penalties incurred that were not previously included within the lease liability.

To the extent that the associated ROU assets and lease liabilities are removed, a corresponding gain or loss is recorded.

If the Company is the primary beneficiary of a VIE, the Company consolidates the entity and reflects any relevant non-controlling interest of other beneficiaries of that entity on the Statement of Consolidated Financial Position.

Aon’s interest in VIEs as of December 31, 2023 was insignificant.

Accounting Standards Issued But Not Yet Adopted

*Improvements to Reportable Segment Disclosures*

In November 2023, the FASB issued new accounting guidance, requiring new segment disclosures under ASC 280, *Segment Reporting,* including disclosure of significant segment expense categories and amounts that are regularly reported to the CODM and included in the segment’s profit or loss.

Additionally, all disclosure requirements under ASC 280 including new requirements under this new guidance, will be required on an interim basis.

The new guidance is effective for Aon for the year ended December 31, 2024 and interim periods thereafter, with early adoption permitted.

An entity will apply the new guidance on a retrospective basis for all periods presented.

The Company is currently evaluating the impact the guidance will have on the Notes to Consolidated Financial Statements.

*Improvements to Income Tax Disclosures*

In December 2023, the FASB issued new accounting guidance under ASC 740, *Income Taxes,* which requires additional income tax disclosures on an annual basis, including disaggregation of information presented within the reconciliation of the expected tax to the reported tax by specific categories, with certain reconciling items 5% or greater broken out by nature and/or jurisdiction.

The new guidance also requires disclosure of income taxes paid, net of refunds, broken out by federal, state/local and foreign, including disclosure of individual jurisdictions when greater than 5% of total net income taxes paid.

The new guidance is effective for Aon for the year ended December 31, 2025, with early adoption permitted.

The Company is evaluating the period of adoption and transition approach, as well as the impact the disclosures will have on the Notes to Consolidated Financial Statements.

| Total revenue | | | | | | $ | 13,376 | | | | | $ | 12,479 | | | | | $ | 12,193 | |

| Total revenue | | | | | | $ | 13,376 | | | | | $ | 12,479 | | | | | $ | 12,193 | |

| | | | | | | 2023 | | | | | | 2022 | | |

4. Accelerating Aon United Program

In the third quarter of 2023, Aon initiated a three-year restructuring program with the purpose of streamlining the Company’s technology infrastructure, optimizing its leadership structure and resource alignment, and reducing the real estate footprint to align to its hybrid working strategy.

The Program will include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation costs.

Program charges are recognized within Accelerating Aon United Program expenses on the accompanying Consolidated Statements of Income and consists of the following cost activities:

*•Technology and other* – includes costs associated with actions taken to rationalize applications, such as contract termination fees and other non-capitalizable costs associated with Program initiatives, which include professional service fees.

*•Workforce optimization* – includes costs associated with headcount reduction and other separation-related costs.

*•Asset impairments* – includes non-cash costs associated with impairment of assets, as they are identified, including ROU lease assets, leasehold improvements, and other capitalized assets no longer providing economic benefit.

The Program is currently expected to result in cumulative costs of approximately $1,000 million, consisting of approximately $900 million of cash charges and approximately $100 million of non-cash charges.

For the year ended December 31, 2023, total Program costs incurred were $135 million.

February 17, 2023

| Balance at January 1, 2020 | | | | | | 232.1 | | | | | | 6,154 | | | | | | 1,248 | | | | | | (4,033) | | | | | | 74 | | | | | | 3,443 | | |

| Net income | | | | | | — | | | | | | — | | | | | | 1,969 | | | | | | — | | | | | | 49 | | | | | | 2,018 | | |

| Shares repurchased | | | | | | (8.5) | | | | | | — | | | | | | (1,763) | | | | | | — | | | | | | — | | | | | | (1,763) | | |

Reclassification

Certain amounts in prior periods' Consolidated Financial Statements have been reclassified to conform to the current year presentation.

In prior periods, commercial paper issuances and repayments were included in Issuance of debt and Repayment of debt, respectively, in the Consolidated Statements of Cash Flows.

The net amount of commercial paper activity is now disclosed separately in Commercial paper issuances, net of repayments in the Consolidated Statements of Cash Flows.

For the year ended December 31, 2021 and December 31, 2020, commercial paper issuances reclassified from Issuance of debt was $4,478 million and $3,162 million, respectively, and commercial paper repayments reclassified from Repayment of debt was $3,807 million and $3,275 million, respectively.

Further information on the gross commercial paper activity for the current and prior year periods is included within the Liquidity and Financial Conditions section of Part II Item 7.

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

In November 2022, Aon incurred a non-cash pension settlement charge of $170 million in connection with the purchase of an annuity for portions of its U.S. pension plans.

Aon has separately classified the non-cash pension settlement charge within Other, net on the Consolidated Statement of Cash Flows as an adjustment to reconcile Net income to Cash provided by operating activities for the period ended December 31, 2022.

Prior year comparable balances have been reclassified to conform with current year presentation.

For the years ended December 31, 2021 and 2020, Aon incurred insignificant non-cash pension settlement charges of $5 million and $2 million, respectively, which were presented as changes in assets and liabilities held within Pension, other postretirement and other postemployment liabilities in the Consolidated Statements of Cash Flows.

See Note 11 “Employee Benefits” for further information regarding the non-cash settlement charges incurred.

In prior periods, Cash paid for employee taxes on withholding shares were included with Proceeds from issuance of shares, and presented as Issuance of shares for employee benefit plans in the Consolidated Statements of Cash Flows.

These items are now presented separately and prior year balances have been reclassified to conform to current year presentation.

For the year ended December 31, 2021 and December 31, 2020, Proceeds from issuance of shares was $55 million and $44 million, respectively, and Cash paid for employee taxes on withholding shares was $185 million and $193 million, respectively.

The customer

future taxable income exclusive of reversing temporary differences and carry-forwards, taxable income in carry-back years, and tax planning strategies that are both prudent and feasible.

The Company does not hold a controlling financial interest over any VIEs that significantly impacts the VIE’s economic performance and the Company does not have rights to any significant benefits or obligations to absorb potentially significant losses.

Thus, the Company does not consolidate any VIEs and Aon’s interest in VIEs as of December 31, 2022 was insignificant.

All issued, but not yet effective, guidance has been deemed not applicable or not significant to the Consolidated Financial Statements.

| | | | | | | | | | | | |

*2021 Acquisitions*

On December 22, 2021, the Company completed the transaction to acquire 100% share capital of For Welfare S.r.l, a company focused on bancassurance programs in Italy.

On September 1, 2021, the Company completed the transaction to acquire 51% of Aon India Insurance Brokers Limited (formerly known as Anviti Insurance Brokers Private Limited).

Prior to the acquisition date, the Company accounted for its 49% interest in Anviti as an equity-method investment.

The acquisition-date fair value of the previous equity interest was $15 million and is included in the measurement of consideration transferred.

There was no significant impact as a result of remeasuring the carrying value of the Company’s prior equity interest in Anviti held before the business combination.

| Balance as of January 1, 2021 | | | $ | 8,666 | |

| Balance as of December 31, 2021 | | | $ | 8,434 | |

| Technology and other | | | 436 | | | | | | 363 | | | | | | 73 | | | | | | 407 | | | | | | 357 | | | | | | 50 | | |

| Tradenames | | | 14 | | | | | | 14 | | | | | | — | | | | | | 14 | | | | | | 13 | | | | | | 1 | | |

| Total | | | | | | $ | 447 | |

7. Debt

| 4.00% Senior Notes due November 2023 (2) | | | 350 | | | | | | 349 | | |

(1)The 2.20% Senior Notes due November 2022 were repaid in full on November 1, 2022.

In November 2022, Aon Global Limited’s $350 million 4.00% Senior Notes due November 2023 were classified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as the date of maturity is in less than one year as of December 31, 2022.

We have conducted an evaluation of the effectiveness of the design and operation of our disclosure controls and procedures, as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) as of the end of the period covered by this annual report of December 31, [removed: 2022.][added: 2023.]

Based on this evaluation, our chief executive officer and chief financial officer concluded as of December 31, [removed: 2022] [added: 2023] that our disclosure controls and procedures were effective such that the information relating to Aon, including our consolidated subsidiaries, required to be disclosed in our SEC reports is recorded, processed, summarized and reported within the time periods specified in SEC rules and forms, and is accumulated and communicated to Aon’s management, including our chief executive officer and chief financial officer, as appropriate to allow timely decisions regarding required disclosure.

Under the supervision and with the participation of our senior management, including our Chief Executive Officer and Chief Financial Officer, we assessed the effectiveness of our internal control over financial reporting as of December 31, [removed: 2022.][added: 2023.]

In making this assessment, we used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission in the *Internal Control — Integrated Framework* (2013 Framework)*.* Based on this assessment, management has concluded our internal control over financial reporting [removed: is] [added: was] effective as of December 31, [removed: 2022.][added: 2023.]

The effectiveness of our internal control over financial reporting as of December 31, [removed: 2022] [added: 2023] has been audited by Ernst & Young, LLP, the Company’s independent registered public accounting firm, as stated in their report [added: included herein] titled “Report of Independent Registered Public Accounting [removed: Firm] [added: Firm-Opinion] on Internal Control over Financial Reporting.”

No changes in Aon’s internal control over financial reporting (as defined in Rule 13a-15(f) under the Exchange Act) occurred during [removed: 2022] [added: the quarter ended December 31, 2023] that have materially affected, or that are reasonably likely to materially affect, Aon’s internal control over financial reporting.

We have audited Aon plc’s internal control over financial reporting as of December 31, [removed: 2022,] [added: 2023,] based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 [removed: Framework),] [added: framework)] (the COSO criteria).

In our opinion, Aon plc (the Company) maintained, in all material respects, effective internal control over financial reporting as of December 31, [removed: 2022,] [added: 2023,] based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated statements of financial position of the Company as of December 31, [removed: 2022] [added: 2023] and [removed: 2021,] [added: 2022,] the related consolidated statements of income, comprehensive income, shareholders' equity (deficit) and cash flows for each of the three years in the period ended December 31, [removed: 2022,] [added: 2023,] and the related notes and our report dated February [removed: 17, 2023] [added: 16, 2024] expressed an unqualified opinion thereon.

[removed: ][added: ]

February 16, 2024

February 17, 2023

The Company is reporting the following information in lieu of reporting on a Current Report on Form 8-K:

Disclosure Pursuant to Item 1.01 of Form 8-K: Entry into a Material Definitive Agreement.

On February 16, 2024, Aon plc (“Parent”), Aon Corporation, Aon Global Holdings plc, Aon Global Limited and Aon North America, Inc. entered into a Credit Agreement (the “Term Loan Agreement”) with Citibank, N.A. (“Citibank”), as administrative agent, the lenders party thereto (collectively, the “Term Lenders”), HSBC Securities (USA) Inc., JPMorgan Chase Bank, N.A. and Morgan Stanley Senior Funding, Inc. as syndication agents, and Citibank, HSBC Securities (USA) Inc., JPMorgan Chase Bank, N.A. and Morgan Stanley Senior Funding, Inc., as joint lead arrangers and joint bookrunners, pursuant to which, subject to the conditions set forth in the Term Loan Agreement, the Term Lenders committed to provide a $2,000,000,000 unsecured term loan facility (the “Term Loan Facility”) to Aon North America, Inc., as borrower.

The proceeds of the Term Loan Facility will be used to fund, in part, the previously announced acquisition (the “Acquisition”) of NFP, by the Acquirer, to fund, in part, the repayment of certain debt of the Target and to pay all or a portion of the related fees and expenses.

The borrowings under the Term Loan Agreement must be made in a single drawing on the closing date of the Acquisition.

Borrowings will bear interest, at the borrower’s option, at an adjusted term SOFR rate or an alternate base rate, in each case, plus an applicable margin based on the public debt rating of Parent’s long-term senior unsecured debt.

In addition, Aon North America, Inc. will pay a commitment fee on the undrawn commitments under the Term Loan Facility during the period from and including May 16, 2024, to but excluding the date on which the commitments under the Term Loan Facility terminate.

The Term Loan Facility will mature on the date that is three years after the closing and funding of the Term Loan Facility and contains financial maintenance covenants with respect to the ratio of consolidated adjusted EBITDA to consolidated interest expense (which may not be less than 4.00 to 1.00) and the ratio of consolidated funded debt to consolidated adjusted EBITDA (which initially may not be more than 4.00 to 1.00, with periodic step-downs to 3.75 to 1.00 and 3.25 to 1.00), subject to certain exceptions, as well as other customary covenants, undertakings and events of default.

Parent and its subsidiaries have other commercial relationships with the Term Lenders, lead arrangers and syndication agents or their affiliates.

In addition, Parent and certain of its affiliates have performed, and may perform, various insurance brokerage and consulting services for the Term Lenders, lead arrangers and syndication agents or their affiliates.

The foregoing summary is qualified in its entirety by reference to the Term Loan Agreement, a copy of which is filed herewith as Exhibit 10.2 and incorporated herein by reference.

Also on February 16, 2024, Aon Corporation, in its capacity as Borrower Representative under each of the Revolving Credit Agreements (as defined below), entered into (i) Amendment No. 1 (“Amendment No. 1”) to the Credit Agreement dated as of October 19, 2023 (as amended, supplemented or otherwise modified from time to time, the “2023 Revolving Credit Agreement”), by and among Parent, Aon Global Limited, Aon Global Holdings plc, Aon Corporation, Aon North America, Inc., Citibank, as administrative agent, and the lenders party thereto from time to time and (ii) Amendment No. 3 (“Amendment No. 3” and, together with Amendment No. 1, the “Amendments”) to the Credit Agreement dated September 28, 2021 (as amended, supplemented or otherwise modified from time to time, the “2021 Revolving Credit Agreement” and, together with the 2023 Revolving Credit Agreement, the “Revolving Credit Agreements”), by and among Parent, Aon Global Limited, Aon Global Holdings plc, Aon Corporation, Aon North America, Inc., Aon UK Limited, Citibank, as administrative agent, and the lenders party thereto from time to time.

The Amendments amend the Revolving Credit Agreements to, among other things, (i) make certain amendments with respect to the financial maintenance covenant with respect to the calculation of the ratio of consolidated funded debt to consolidated adjusted EBITDA, including to (a) permit the netting of unrestricted cash against debt in connection with the calculation thereof for periods ending prior to the closing of the Acquisition and (b) increase the applicable ratio thereunder for the first six fiscal quarters following the closing of the Acquisition to conform to those applicable under the Term Loan Agreement and (ii) make certain other conforming changes to align with the terms of the Term Loan Agreement.

Parent and its subsidiaries have other commercial relationships with the lenders, lead arrangers and bookrunners and the syndication agent under the Revolving Credit Agreements and their respective affiliates.

In addition, Parent and certain of its affiliates have performed, and may perform, various insurance brokerage and consulting services for the lenders, lead arrangers and bookrunners and the syndication agent under the Revolving Credit Agreements and/or their respective affiliates.

The foregoing description of the Amendments does not purport to be complete and is qualified in its entirety by reference to the full text of each Amendment, copies of which are filed herewith as Exhibit 10.3 and Exhibit 10.4 and incorporated herein by reference.

Disclosure Pursuant to Item 2.03 of Form 8-K: Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information set forth above in Disclosure Pursuant to Item 1.01 of Form 8-K regarding the entry into the Term Loan Agreement is incorporated herein by reference.

Not applicable.

Information relating to Aon’s directors is set forth under the heading “Proposal 1 — Resolutions Regarding the Election of Directors” in the Proxy Statement for the [removed: 2023] [added: 2024] Annual General Meeting of Shareholders (the “Proxy Statement”) and is incorporated herein by reference.

| | | | Consolidated Statements of Financial Position — As of December 31, [removed: 2022] [added: 2023] and [removed: 2021] [added: 2022] | | | | | |

| | | | Consolidated Statements of Income — Years Ended December 31, [added: 2023,] 2022, [removed: 2021,] and [removed: 2020] [added: 2021] | | | | | |

| | | | Consolidated Statements of Comprehensive Income — Years Ended December 31, [removed: 2022, 2021] [added: 2023, 2022] and [removed: 2020] [added: 2021] | | | | | |

| | | | Consolidated Statements of Shareholders’ Equity — Years Ended December 31, [removed: 2022, 2021] [added: 2023, 2022] and [removed: 2020] [added: 2021] | | | | | |

| | | | Consolidated Statements of Cash Flows — Years Ended December 31, [removed: 2022, 2021] [added: 2023, 2022] and [removed: 2020] [added: 2021] | | | | | |

| | | | | | | 3.1* | | | [Memorandum and Articles of Association of Aon plc [removed: -] incorporated by reference to Exhibit 3.1 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed June 4, 2021.](http://www.sec.gov/Archives/edgar/data/0000315293/000119312521183025/d162116dex31.htm) | | |

| | | | | | | [removed: 4.25] [added: 4.25*] | | | [Description of Securities of Aon plc that are registered under Section 12 of the Securities Exchange Act of [removed: 193](https://www.sec.gov/Archives/edgar/data/315293/000162828023004087/exhibit4252022.htm)[4,] [added: 1934,] as [removed: amended](https://www.sec.gov/Archives/edgar/data/315293/000162828023004087/exhibit4252022.htm).] [added: amended – incorporated by reference to Exhibit 4.25 to Aon’s Annual Report on Form 10-K filed February 17, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828023004087/exhibit4252022.htm)] | | |

| | | | | | | 10.1* | | | [$1,000,000,000 Credit Agreement, dated September 28, 2021, among Aon plc, Aon Corporation, Aon UK Limited, Aon Global Holdings plc and Aon Global Limited with Citibank, N.A., as administrative agent, the lenders party thereto, HSBC Bank USA, National Association and Morgan Stanley Senior Funding, Inc., as syndication agents, and Citibank, N.A., HSBC Securities (USA) and Morgan Stanley Senior Funding, Inc., as joint lead arrangers and joint bookrunners [removed: -] incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed on September 30, 2021.](http://www.sec.gov/Archives/edgar/data/0000315293/000119312521287444/d222574dex101.htm) | | |

| | | | | | | [removed: 10.2*] [added: 10.8*] | | | [$400,000,000 [removed: Five-Year] [added: Five Year] Credit Agreement, dated October 19, 2017 (the “2017 Credit Agreement”), among Aon plc, Aon Corporation, Citibank, N.A., as administrative agent, the lenders party thereto, HSBC Bank USA, National Association, as syndication agent, and Citigroup Global Markets, Inc. and HSBC Securities (USA) Inc., as joint lead arrangers and joint bookrunners [removed: -] incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed October 20, 2017.](http://www.sec.gov/Archives/edgar/data/315293/000110465917063130/a17-24239_1ex10d1.htm) | | |

| | | | | | | [removed: 10.3*] [added: 10.9*] | | | [Form of Notice of Extension of the 2017 Credit Agreement [removed: -] incorporated by reference to Exhibit 10.7 to Aon’s Annual Report on Form [removed: 10-K] [added: 10 K] for the year ended December 31, 2019.](http://www.sec.gov/Archives/edgar/data/315293/000162828020001607/exhibit1072019.htm) | | |

| | | | | | | [removed: 10.4*] [added: 10.10*] | | | [Lender Assumption Agreement, dated February 27, 2020, among Aon plc, Citibank, N.A. and the parties thereto, with respect to the 2017 Credit Agreement [removed: -] incorporated by reference to Exhibit 10.12 to Aon’s Quarterly Report on Form [removed: 10-Q] [added: 10 Q] for the quarter ended March 31, 2020.](http://www.sec.gov/Archives/edgar/data/315293/000162828020006142/exhibit1012.htm) | | |

| | | | | | | [removed: 10.5*] [added: 10.11*] | | | [Waiver and Amendment No. 1 to the 2017 Credit Agreement, dated April 1, 2020, among Aon plc, Aon Corporation, Citibank, N.A. and the lenders party thereto [removed: -] incorporated by reference to Exhibit 10.11 to Aon’s Quarterly Report on Form [removed: 10-Q] [added: 10 Q] for the quarter ended March 31, 2020.](http://www.sec.gov/Archives/edgar/data/315293/000162828020006142/exhibit1011.htm) | | |

| | | | | | | [removed: 10.6*] [added: 10.12*] | | | [Amendment No. 2 to the 2017 Credit Agreement, dated September 28, 2021, among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Citibank, N.A., as administrative agent, and the lenders party thereto [removed: -] incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed on September 30, 2021.](http://www.sec.gov/Archives/edgar/data/0000315293/000119312521287444/d222574dex102.htm) | | |

| | | | | | | [removed: 10.7*] [added: 10.13*] | | | [Amendment No. 3 to the 2017 Credit Agreement, dated [removed: Octob](http://www.sec.gov/Archives/edgar/data/315293/000119312522266744/d303395dex101.htm)[e](http://www.sec.gov/Archives/edgar/data/315293/000119312522266744/d303395dex101.htm)[r] [added: October] 19, 2022, among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global limited, Citibank, N.A., as administrative agent, and the lenders party thereto – incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed on October 21, 2022.](http://www.sec.gov/Archives/edgar/data/315293/000119312522266744/d303395dex101.htm) | | |

| | | | | | | [removed: 10.8*] [added: 10.15*] | | | [Purchase Agreement, dated February 9, 2017, between Aon plc and Tempo Acquisition, LLC [removed: -] incorporated by reference to Exhibit 2.1 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed February 10, 2017.](http://www.sec.gov/Archives/edgar/data/315293/000110465917007945/a17-4192_1ex2d1.htm) | | |

| | | | | | | [removed: 10.9*] [added: 10.16*] | | | [Amendment No. 1 to Purchase Agreement, dated April 17, 2017, between Aon plc and Tempo Acquisition, LLC [removed: -] incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on [removed: 10-Q] [added: 10 Q] for the quarter ended March 31, 2017.](http://www.sec.gov/Archives/edgar/data/315293/000162828017005272/exhibit102.htm) | | |

| | | | | | | [removed: 10.10*#] [added: 10.17*#] | | | [Deed of Assumption of Aon plc, dated April 1, 2020 - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.](http://www.sec.gov/Archives/edgar/data/315293/000119312520093512/d867242dex101.htm) | | |

| | | | | | | [removed: 10.11*#] [added: 10.18*#] | | | [Deed of Assumption of Aon Global Limited, dated April 2, 2012 - incorporated by reference to Exhibit 10.7 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.](http://www.sec.gov/Archives/edgar/data/315293/000110465912023043/a12-8467_1ex10d7.htm) | | |

| | | | | | | [removed: 10.12*#] [added: 10.19*#] | | | [Aon Corporation Outside Director Corporate Bequest Plan (as amended and restated, effective January 1, 2010) - incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2010.](http://www.sec.gov/Archives/edgar/data/315293/000110465910042738/a10-12609_1ex10d1.htm) | | |

| | | | | | | [removed: 10.13*#] [added: 10.20*#] | | | [Amended and Restated Aon Stock Incentive Plan - incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed May 24, 2006.](http://www.sec.gov/Archives/edgar/data/315293/000110465906037278/a06-12524_1ex10d2.htm) | | |

| | | | | | | [removed: 10.14*#] [added: 10.21*#] | | | [First Amendment to the Amended and Restated Aon Stock Incentive Plan - incorporated by reference to Exhibit 10(au) to Aon’s Annual Report on Form 10-K for the year ended December 31, 2006.](http://www.sec.gov/Archives/edgar/data/315293/000104746907001537/a2176366zex-10_au.htm) | | |

| | | | | | | [removed: 10.15*#] [added: 10.22*#] | | | [Second Amendment to the Amended and Restated Aon Stock Incentive Plan, dated April 2, 2012 - incorporated by reference to Exhibit 10.10 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.](http://www.sec.gov/Archives/edgar/data/315293/000110465912023043/a12-8467_1ex10d10.htm) | | |

| | | | | | | [removed: 10.16*#] [added: 10.24*#] | | | [Aon Stock Award Plan (as amended and restated through February 2000) - incorporated by reference to Exhibit 10(a) to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2000.](http://www.sec.gov/Archives/edgar/data/315293/000094857200000044/0000948572-00-000044-0002.txt) | | |

| | | | | | | [removed: 10.17*#] [added: 10.25*#] | | | [First Amendment to the Aon Stock Award Plan - incorporated by reference to Exhibit 10(as) to Aon’s Annual Report on Form 10-K for the year ended December 31, 2006.](http://www.sec.gov/Archives/edgar/data/315293/000104746907001537/a2176366zex-10_as.htm) | | |

| | | | | | | [removed: 10.18*#] [added: 10.26*#] | | | [Aon plc 2011 Incentive Plan (as amended and restated, effective March 29, 2019) - incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2019.](http://www.sec.gov/Archives/edgar/data/315293/000162828019009103/a101aonplcamendedandre.htm) | | |

| | | | | | | [removed: 10.19*#] [added: 10.27*#] | | | [First Amendment to the Aon plc 2011 Incentive Plan, effective September 13, 2021 - incorporated by reference to Exhibit 10.9 to Aon’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2021.](http://www.sec.gov/Archives/edgar/data/315293/000162828021020852/a109firstamendmenttotheaon.htm) | | |

| | | | | | | [removed: 10.20*#] [added: 10.29*#] | | | [Aon plc Leadership Performance Program (as amended and restated, effective January 1, 2021) - incorporated by reference to Exhibit 10.20 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2021.](http://www.sec.gov/Archives/edgar/data/315293/000162828022003180/exhibit10202021.htm) | | |

| | | | | | | [removed: 10.21*#] [added: 10.30*#] | | | [Aon plc Senior Executive Combined Severance and Change in Control Plan (as amended and restated, effective June 21, 2019) - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter end June 30, 2019.](http://www.sec.gov/Archives/edgar/data/0000315293/000162828019009103/a102-tiericicandsevera.htm) | | |

| | | | | | | [removed: 10.22*#] [added: 10.31*#] | | | [First Amendment to the Aon plc Amended and Restated Senior Executive Combined Severance and Change in Control Plan, effective September 30, 2021 - incorporated by reference to Exhibit 10.10 to Aon’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2021.](http://www.sec.gov/Archives/edgar/data/315293/000162828021020852/a1010firstamendmenttotheao.htm) | | |

| | | | | | | [removed: 10.23*#] [added: 10.32*#] | | | [Aon plc Senior Executive Incentive Compensation Plan (as amended and restated, effective January 1, 2021) - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2021.](http://www.sec.gov/Archives/edgar/data/315293/000162828021008451/a102aonplcseniorexecutivei.htm) | | |

| | | | | | | [removed: 10.24*#] [added: 10.33*#] | | | [Form of Deed of Indemnity of Aon plc - incorporated by reference to Exhibit 10.4 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.](http://www.sec.gov/Archives/edgar/data/315293/000119312520093512/d867242dex104.htm) | | |

| | | | | | | [removed: 10.25*#] [added: 10.34*#] | | | [Form of Deed of Indemnity for Directors of Aon Global Limited - incorporated by reference to Exhibit 10.4 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.](http://www.sec.gov/Archives/edgar/data/315293/000110465912023043/a12-8467_1ex10d4.htm) | | |

| | | | | | | [removed: 10.26*#] [added: 10.35*#] | | | [Form of Deed of Indemnity for Gregory C. Case - incorporated by reference to Exhibit 10.5 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.](http://www.sec.gov/Archives/edgar/data/315293/000110465912023043/a12-8467_1ex10d5.htm) | | |

| | | | | | | [removed: 10.27*#] [added: 10.35*#] | | | [Form of Deed of Indemnity for Executive Officers of Aon plc [removed: -] incorporated by reference to Exhibit 10.6 to Aon’s Current Report on Form [removed: 8-K12B] [added: 8 K12B] filed April 2, 2012.](http://www.sec.gov/Archives/edgar/data/315293/000110465912023043/a12-8467_1ex10d6.htm) | | |

| | | | | | | [removed: 10.28*#] [added: 10.36*#] | | | [Form of Service as a [removed: Non-Executive] [added: Non Executive] Director Agreement [removed: -] incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form [removed: 10-Q] [added: 10 Q] for the quarter ended September 30, 2016.](http://www.sec.gov/Archives/edgar/data/315293/000162828016020443/a102formofserviceagreement.htm) | | |

| | | | | | | [removed: 10.29*#] [added: 10.37*#] | | | [Amended and Restated Employment Agreement, dated January 16, 2015, among Aon plc, Aon Corporation and Gregory C. Case [removed: -] incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed January 23, 2015.](http://www.sec.gov/Archives/edgar/data/315293/000110465915004064/a15-2842_1ex10d1.htm) | | |

| | | | | | | [removed: 10.30*#] [added: 10.38*#] | | | [Amendment to Employment Agreement, dated April 20, 2018, among Aon plc, Aon Corporation and Gregory C. Case [removed: -] incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed April 25, 2018.](http://www.sec.gov/Archives/edgar/data/0000315293/000119312518129799/d571873dex102.htm) | | |

| | | | | | | [removed: 10.31*#] [added: 10.39*#] | | | [Amendment to Employment Agreement, dated May 10, 2018, by and among Aon plc, Aon Corporation, and Gregory C. Case [removed: -] incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed on May 15, 2018.](http://www.sec.gov/Archives/edgar/data/315293/000119312518163426/d566365dex101.htm) | | |

| | | | | | | [removed: 10.32*#] [added: 10.40*#] | | | [Amendment to Employment Agreement, dated July 26, 2021, among Aon plc, Aon Corporation and Gregory C. Case [removed: -] incorporated by reference to Exhibit 10.3 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed on July 26, 2021.](http://www.sec.gov/Archives/edgar/data/0000315293/000119312521223710/d208525dex103.htm) | | |

| | | | | | | [removed: 10.33*#] [added: 10.41*#] | | | [Amended and Restated Change in Control Agreement, dated November 13, 2009, between Aon Corporation and Gregory C. Case [removed: -] incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form [removed: 8-K] [added: 8 K] filed on November 17, [removed: 2009.](http://www.sec.gov/Archives/edgar/data/315293/000110465909065386/a09-33622_1ex10d2.htm)] [added: 2009.](https://www.sec.gov/Archives/edgar/data/315293/000110465909065386/a09-33622_1ex10d2.htm)] | | |

| | | | Plan of Acquisition, Reorganization, Arrangement, Liquidation or Succession. | | | | | | | | |

| | | | | | | 2.1* | | | [Agreement and Plan of Merger, by and among Aon plc, Randolph Acquisition Corp., Randolph Merger Sub LLC, NFP Intermediate Holdings A Corp. and NFP Parent Co, LLC, dated as of December 19, 2023 — incorporated by reference to Exhibit 2.1 to Aon’s Current Report on Form 8 K filed December 20, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523299956/d677052dex21.htm) | | |

| | | | | | | 4.36* | | | [Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, AGL, AGH and the Trustee (amending and restating the Indenture, dated December 3, 2018, among Aon Corporation, AGL and the Trustee) (included in Exhibit 4.6 to the Current Report on Form 8 K12B filed by Aon on April 1, 2020) — incorporated by reference to Exhibit 4.1 to Aon’s Current Report on Form 8 K filed February 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312520093512/d867242dex46.htm) | | |

| | | | | | | 4.37* | | | [Fifth Indenture Supplement, dated as of February 28, 2023, among Aon Corporation, AGH, the Guarantors and the Trustee — incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8 K filed February 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523054079/d474704dex42.htm) | | |

| | | | | | | 4.38* | | | [Form of 5.350% Senior Notes due 2033 (included in Exhibit 4.2 to the Current Report on Form 8 K filed by Aon on February 28, 2023) — incorporated by reference to Exhibit 4.3 to Aon’s Current Report on Form 8 K filed February 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523054079/d474704dex42.htm) | | |

| | | | | | | 4.39* | | | [First Indenture Supplement, dated June 22, 2023, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc, Aon North America, Inc. and The Bank of New York Mellon Trust Company, N.A. — incorporated by reference to Exhibit 4.14 to Aon’s Registration Statement on Form S 3 filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523171894/d479772dex414.htm) | | |

| | | | | | | 4.40* | | | [First Indenture Supplement, dated June 22, 2023, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc, Aon North America, Inc. and The Bank of New York Mellon Trust Company, N.A. — incorporated by reference to Exhibit 4.16 to Aon’s Registration Statement on Form S 3 filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523171894/d479772dex416.htm) | | |

| | | | | | | 4.41* | | | [First Indenture Supplement, dated June 22, 2023, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc, Aon North America, Inc. and The Bank of New York Mellon Trust Company, N.A. — incorporated by reference to Exhibit 4.18 to Aon’s Registration Statement on Form S 3 filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523171894/d479772dex418.htm) | | |

| | | | | | | 4.42* | | | [First Indenture Supplement, dated June 22, 2023, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc, Aon North America, Inc. and The Bank of New York Mellon Trust Company, N.A. — incorporated by reference to Exhibit 4.20 to Aon’s Registration Statement on Form S 3 filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523171894/d479772dex420.htm) | | |

| | | | | | | 4.43* | | | [First Indenture Supplement, dated June 22, 2023, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc, Aon North America, Inc. and The Bank of New York Mellon Trust Company, N.A. — incorporated by reference to Exhibit 4.22 to Aon’s Registration Statement on Form S 3 filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523171894/d479772dex422.htm) | | |

| | | | | | | 4.44* | | | [Sixth Indenture Supplement, dated June 22, 2023, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc, Aon North America, Inc. and The Bank of New York Mellon Trust Company, N.A. — incorporated by reference to Exhibit 4.29 to Aon’s Registration Statement on Form S 3 filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523171894/d479772dex429.htm) | | |

| | | | | | | 10.2 | | | [Term Loan Credit Agreement, dated as of February 16, 2024, by and among, Aon North America, Inc., Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Citibank, N.A., as administrative agent, HSBC Securities (USA) Inc., JPMorgan Chase Bank, N.A., and Morgan Stanley Senior Funding, Inc. as syndication agents, and the lenders party thereto.](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit1022023.htm) | | |

| | | | | | | 10.3 | | | [Amendment No. 1 to the Credit Agreement, dated as of February 16, 2024, by and among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited and Aon North America, Inc., Citibank, N.A., as administrative agent, and the lenders party thereto.](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit103-amendmentnoic.htm) | | |

| | | | | | | 10.4 | | | [Amendment No. 3 to the Credit Agreement, dated as of February 16, 2024, by and among Aon plc, Aon Corporation,](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit104-xannexixamend.htm) [](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit104-xannexixamend.htm)[Aon Global Holdings plc, Aon Global Limited, Aon UK Limited and Aon North America, Inc., Citibank, N.A.,](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit104-xannexixamend.htm) [](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit104-xannexixamend.htm)[as administrative agent and the lenders party theret](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit104-xannexixamend.htm)[o.](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/exhibit104-xannexixamend.htm) | | |

| | | | | | | 10.5 | | | [Amendment No. 1 to the Credit Agreement, dated as of May 3, 2023, by and among Citibank, N.A., as administrative agent, Aon Corporation, Aon UK Limited, Aon Global Holdings plc and Aon Global Limited, and the lenders party thereto — incorporated by reference to Exhibit 10.4 to Aon’s Quarterly Report on Form 10 Q filed July 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828024005392/aon-amendmentno1to2021cr.htm) | | |

| | | | | | | 10.6* | | | [Amendment No. 2 to the Credit Agreement, dated as of October 19, 2023, among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Aon UK Limited and Aon North America, Inc., Citibank, N.A., as administrative agent and the lenders party thereto — incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8 K filed October 24, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523261702/d554372dex102.htm) | | |

| | | | | | | 10.7* | | | [Guaranty Supplement from Aon North America, Inc. to Citibank, N.A., as administrative agent, dated June 22, 2023 — incorporated by reference to Exhibit 10.6 to Aon’s Quarterly Report on Form 10 Q filed July 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828023026117/exhibit1062023.htm) | | |

| | | | | | | 10.14* | | | [Guaranty Supplement from Aon North America, Inc. to Citibank, N.A., as administrative agent, dated June 22, 2023 — incorporated by reference to Exhibit 10.5 to Aon’s Quarterly Report on Form 10 Q filed July 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828023026117/exhibit1052023.htm) | | |

| | | | | | | 10.28*# | | | [Aon plc 2011 Incentive Plan (as amended and restated effective April 19, 2023) — incorporated by reference to Exhibit 10.3 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30,](https://www.sec.gov/Archives/edgar/data/315293/000162828023026117/exhibit1032023.htm) [2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828023026117/exhibit1032023.htm) | | |

| | | | | | | 10.49*# | | | [Amendment to International Assignment Letter, dated June 16, 2023, between Aon Corporation and Gregory C. Case — incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8 K filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523172661/d507239dex102.htm) | | |

| | | | | | | 10.61*# | | | [Amendment to International Assignment Letter, dated June 16, 2023, between Aon Corporation and Christa Davies — incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8 K filed June 22, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523172661/d507239dex101.htm) | | |

| | | | | | | 10.86*# | | | [Form of Restricted Stock Unit Agreement — incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10 Q filed April 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828023014187/exhibit1012023.htm) | | |

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| | | | | | | 10.87*# | | | [Employment Agreement, effective as of July 1, 2023, between Aon Corporation and Eric Andersen — incorporated by reference to Exhibit 10.7 to Aon’s Quarterly Report on Form 10 Q filed July 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828023026117/exhibit1072023.htm) | | |

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| | | | | | | 10.88*# | | | [Form of Performance Share Unit Agreement Under Aon plc 2011 Incentive Plan, as amended as restated — incorporated by reference to Exhibit 10.8 to Aon’s Quarterly Report on Form 10 Q filed July 28, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000162828023026117/exhibit1082023.htm) | | |

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| | | | | | | 10.89* | | | [Credit Agreement dated as of October 19, 2023, among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited and Aon North America, Inc., Citibank, N.A., as administrative agent, and the lenders party thereto — incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8 K filed October 24, 2023.](https://www.sec.gov/Archives/edgar/data/315293/000119312523261702/d554372dex101.htm) | | |

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Item16.

Form 10-K Summary

None.

SIGNATURES

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

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | | | | | | | Aon plc | | | | | | | | |

| | | | | | | | | | By: | | | | | | /s/ GREGORY C. CASE | | |

| | | | | | | | | | | | | | | | Gregory C. Case, Chief Executive Officer | | |

| Date: | | | February 17, 2023 | | | | | | | | | | | | | | |

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

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| Signature | | | | | | Title | | | | | | Date | | |

| /s/ GREGORY C. CASE | | | | | | Chief Executive Officer and Director (Principal Executive Officer) | | | | | | February 17, 2023 | | |

| Gregory C. Case | | | | | | | | | | | | | | |

| /s/ LESTER B. KNIGHT | | | | | | Non-Executive Chairman and Director | | | | | | February 17, 2023 | | |

| Lester B. Knight | | | | | | | | | | | | | | |

| /s/ JIN-YONG CAI | | | | | | Director | | | | | | February 17, 2023 | | |

| Jin-Yong Cai | | | | | | | | | | | | | | |

| /s/ JEFFREY C. CAMPBELL | | | | | | Director | | | | | | February 17, 2023 | | |

| Jeffrey C. Campbell | | | | | | | | | | | | | | |

| /s/ FULVIO CONTI | | | | | | Director | | | | | | February 17, 2023 | | |

| Fulvio Conti | | | | | | | | | | | | | | |

| /s/ CHERYL A. FRANCIS | | | | | | Director | | | | | | February 17, 2023 | | |

| Cheryl A. Francis | | | | | | | | | | | | | | |

| /s/ ADRIANA KARABOUTIS | | | | | | Director | | | | | | February 17, 2023 | | |

| Adriana Karaboutis | | | | | | | | | | | | | | |

| /s/ J. MICHAEL LOSH | | | | | | Director | | | | | | February 17, 2023 | | |

| J. Michael Losh | | | | | | | | | | | | | | |

| /s/ RICHARD C. NOTEBAERT | | | | | | Director | | | | | | February 17, 2023 | | |

| Richard C. Notebaert | | | | | | | | | | | | | | |

| /s/ GLORIA SANTONA | | | | | | Director | | | | | | February 17, 2023 | | |

| Gloria Santona | | | | | | | | | | | | | | |

| /s/ BYRON SPRUELL | | | | | | Director | | | | | | February 17, 2023 | | |

| Byron Spruell | | | | | | | | | | | | | | |

| /s/ CAROLYN Y. WOO | | | | | | Director | | | | | | February 17, 2023 | | |

| Carolyn Y. Woo | | | | | | | | | | | | | | |

| /s/ CHRISTA DAVIES | | | | | | Chief Financial Officer (Principal Financial Officer) | | | | | | February 17, 2023 | | |

None.

SIGNATURES

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

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | | | | | | | Aon plc | | | | | | | | |

| | | | | | | | | | By: | | | | | | /s/ GREGORY C. CASE | | |

| | | | | | | | | | | | | | | | Gregory C. Case, Chief Executive Officer | | |

| Date: | | | February 16, 2024 | | | | | | | | | | | | | | |

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

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| Signature | | | | | | Title | | | | | | Date | | |

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| /s/ GREGORY C. CASE | | | | | | Chief Executive Officer and Director (Principal Executive Officer) | | | | | | February 16, 2024 | | |

| Gregory C. Case | | | | | | | | | | | | | | |

| | | | | | | | | | | | | | | |

| /s/ LESTER B. KNIGHT | | | | | | Non-Executive Chairman and Director | | | | | | February 16, 2024 | | |

| Lester B. Knight | | | | | | | | | | | | | | |

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| /s/ JOSE ANTONIO ÁLVAREZ | | | | | | Director | | | | | | February 16, 2024 | | |

| Jose Antonio Álvarez | | | | | | | | | | | | | | |

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| /s/ JIN-YONG CAI | | | | | | Director | | | | | | February 16, 2024 | | |

| Jin-Yong Cai | | | | | | | | | | | | | | |

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| /s/ JEFFREY C. CAMPBELL | | | | | | Director | | | | | | February 16, 2024 | | |

| Jeffrey C. Campbell | | | | | | | | | | | | | | |

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| /s/ FULVIO CONTI | | | | | | Director | | | | | | February 16, 2024 | | |

| Fulvio Conti | | | | | | | | | | | | | | |

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| /s/ CHERYL A. FRANCIS | | | | | | Director | | | | | | February 16, 2024 | | |

| Cheryl A. Francis | | | | | | | | | | | | | | |

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| /s/ ADRIANA KARABOUTIS | | | | | | Director | | | | | | February 16, 2024 | | |

| Adriana Karaboutis | | | | | | | | | | | | | | |

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| /s/ RICHARD C. NOTEBAERT | | | | | | Director | | | | | | February 16, 2024 | | |

| Richard C. Notebaert | | | | | | | | | | | | | | |