Marsh McLennan Third Quarter 2021 Investor Presentation

INVESTOR PRESENTATION

Results through Third Quarter 2021

Forward-Looking Statements

This presentation contains "forward-looking statements," as defined in the Private Securities Litigation Reform Act of1995. These statements, which express management's current views concerning future events or results, use words like "anticipate," "assume," "believe," "continue," "estimate," "expect," "intend," "plan," "project" and similar terms, and future or conditional tense verbs like "could," "may," "might," "should," "will" and "would".

Forward-looking statements are subject to inherent risks and uncertainties that could cause actual results to differ materially from those expressed or implied in our forward-looking statements. Factors that could materially affect our future results include, among other things: 1) the increasing prevalence of ransomware, supply chain and other forms of cyber attacks, and their potential to disrupt our operations and result in the disclosure of confidential client or company information; 2) the impact from lawsuits or investigations arising from errors and omissions, breaches of fiduciary duty or other claims against us in our capacity as a broker or investment advisor; 3) increased regulatory activity and scrutiny by regulatory or law enforcement authorities; 4) the financial and operational impact of complying with laws and regulations where we operate and the risks of noncompliance with such laws by us or third-party providers, including anti-corruption laws such as the U.S. Foreign Corrupt Practices Act, U.K. Anti-Bribery Act and cybersecurity and data privacy regulations such as the E.U.'s General Data Protection Regulation; 5) the impact of COVID-19, including emerging vaccine mandates, on our business operations, results of operations, cash flows and financial position; 6) our ability to compete effectively and adapt to changes in the competitive environment, including to respond to technological change, disintermediation, digital disruption and other types of innovation; 7) our ability to manage risks associated with our investment management and related services business, particularly in the context of uncertain equity markets, including our ability to execute timely trades in light of increased trading volume and to manage potential conflicts of interest; 8) our ability to attract and retain industry leading talent; 9) the impact of changes in tax laws, guidance and interpretations, or disagreements with tax authorities; and 10) the regulatory, contractual and reputational risks that arise based on insurance placement activities and insurer revenue streams.

The factors identified above are not exhaustive. Marsh McLennan and its subsidiaries operate in a dynamic business environment in which new risks emerge frequently. Accordingly, we caution readers not to place undue reliance on any forward-looking statements, which are based only on information currently available to us and speak only as of the dates on which they are made. The Company undertakes no obligation to update or revise any forward-looking statement to reflect events or circumstances arising after the date on which it is made.

Further information concerning Marsh McLennan and its businesses, including information about factors that could materially affect our results of operations and financial condition, is contained in the Company's filings with the Securities and Exchange Commission, including the "Risk Factors" section and the "Management's Discussion and Analysis of Financial Condition and Results of Operations" section of our most recently filed Annual Report on Form 10-K.

Explanation of Non-GAAP Measures

This presentation also contains certain financial measures that are "non-GAAP measures," within the meaning of Regulation G of the Securities Exchange Act of 1934, as amended. The Company believes these non-GAAP financial measures provide useful supplemental information that enables investors to better compare the Company's performance across periods. Management also uses these measures internally to assess the operating performance of its business, to assess performance for employee compensation purposes and to decide how to allocate resources. However, investors should not consider these non-GAAP measures in isolation from, or as a substitute for, the financial information that the Company reports in accordance with GAAP. The Company's non-GAAP measures include adjustments that reflect how management views our businesses, and may differ from similarly titled non-GAAP measures presented by other companies. Please see the Appendix to this presentation for a reconciliation of non-GAAP measures to the closest comparable applicable GAAP measures.

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1. Overview & Opportunity
2. A Compelling Investment
3. Appendix

The Global Leader in Advisory on Risk, Strategy and People

150-year history of leadership and innovation

Revenue of over $19 billion* Over $100billion of premiums placed globally

Top 100 S&P 500 constituent by market value** $397 billion delegatedassets under management**

81,000 colleagues globally	$16 trillion of retirement assets under advisement
Clients in 130 countries	Advisor to95% of the Fortune 1000®i companies

*12 months ended 09/30/2021; **As of 10/27/2021; iFORTUNE 1000® is a trademark of FORTUNE Media IP and is used under license.

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A Preeminent Global Professional Services Firm

#1 Insurance Broker

#1 Broker of U.S. Business

#1 Health & Benefits Broker

#1 Assets Under Advisement

#1 Outsourced CIO

Sources: Business Insurance and Pensions & Investments.

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