Item 1. Business.

References in this report to "we", "us" and "our" are to Marsh & McLennan Companies, Inc. and its consolidated subsidiaries (the "Company"), unless the context otherwise requires.

GENERAL

The Company is a global professional services firm offering clients advice in the areas of risk, strategy and people. The Company's 76,000 colleagues advise clients in over 130 countries. With annual revenue of $17 billion, the Company helps clients navigate an increasingly dynamic and complex environment through four market-leading businesses. Marsh advises individual and commercial clients of all sizes on insurance broking and innovative risk management solutions. Guy Carpenter develops advanced risk, reinsurance and capital strategies that help clients grow profitably and pursue emerging opportunities. Mercer delivers advice and technology-driven solutions that help organizations redefine the world of work, reshape retirement and investment outcomes, and unlock health and wellbeing for a changing workforce. Oliver Wyman Group serves as critical strategic, economic and brand advisor to private sector and governmental clients.

The Company conducts business through two segments:

• Risk and Insurance Services** includes risk management activities (risk advice, risk transfer and risk control and mitigation solutions) as well as insurance and reinsurance broking and services. The Company conducts business in this segment through Marsh and Guy Carpenter.

• Consulting** includes health, wealth and career services and products, and specialized management, economic and brand consulting services. The Company conducts business in this segment through Mercer and Oliver Wyman Group.

We describe our current segments in further detail below. We provide financial information about our segments in our consolidated financial statements included under Part II, Item 8 of this report.

OUR BUSINESSES

RISK AND INSURANCE SERVICES

The Risk and Insurance Services segment generated approximately 60% of the Company's total revenue in 2020 and employs approximately 44,100 colleagues worldwide. The Company conducts business in this segment through Marsh and Guy Carpenter.

MARSH

Marsh is the leading global insurance broker and risk advisor, serving companies, institutions and individuals. From its founding in 1871 to the present day, Marsh has demonstrated a commitment to thought leadership, innovation and insurance expertise to meet its clients’ needs. Marsh’s pioneering contributions include introducing the practice of client representation through brokerage, the discipline of risk management, the globalization of risk management services and the development of service platforms that identify, quantify, mitigate and transfer risk.

Currently, approximately 41,000 Marsh colleagues provide risk management, insurance broking, insurance program management services, risk consulting, analytical modeling and alternative risk financing services to a wide range of businesses, government entities, professional service organizations and individuals in more than 130 countries. Marsh generated approximately 50% of the Company's total revenue in 2020.

Insurance Broking and Risk Advisory

In its core insurance broking and risk advisory business, Marsh employs a team approach to identify, quantify and address clients' risk management and insurance needs. Marsh’s product and service offerings include risk analysis, insurance program design and placement, insurance program support and administration, claims support and advocacy, alternative risk strategies and a wide array of risk analysis and risk management consulting services. Clients benefit from Marsh’s advanced analytics, deep technical expertise, specialty and industry knowledge, collaborative global culture and the ability to

develop innovative solutions and products. The firm’s resources also include nearly three dozen specialty and industry practices, including cyber, financial and professional service practices, along with a growing employee health & benefits business.

Marsh provides services to clients of all sizes, including large multinational companies ("Risk Management"), high growth middle-market businesses ("Corporate"), small commercial enterprises and high net-worth private clients, and affinity group members ("Commercial & Consumer"). Marsh's segments are designed to build stronger value propositions and operating models to optimize solutions and services for clients depending on their needs.

Risk Management. Marsh has an extensive global footprint and market-leading advisory and placement services that benefit large domestic and international companies and institutions facing complex risk exposures. These clients are also supported by Marsh’s robust analytics and a growing digital experience.

In addition, Marsh’s largest global clients are serviced by Multinational Client Services, a dedicated team of colleagues from around the world focused on delivering service excellence and insurance solutions to clients wherever they are located. Marsh is digitizing the client experience through tools such as LINQ, Marsh’s account and service application; Blue[i], a suite of analytics tools for clients; and Bluestream, a digital brokerage platform that enables clients to provide insurance to their customers or suppliers in a B2B2C distribution model. Marsh provides global expertise and an intimate knowledge of local markets, helping clients navigate local regulatory environments to address the worldwide risk issues that confront them.

• Marsh JLT Specialty**. Marsh’s specialty unit combined with JLT Specialty to form Marsh JLT Specialty as part of the 2019 acquisition of Jardine Lloyd Thompson Group plc ("JLT"). The new unit offers leading expertise, global service and data-driven insights to clients across seven global specialties: aviation; credit specialties; financial & professional services; private equity & mergers & acquisitions; construction; energy & power; and marine & cargo. These teams of specialist experts are globally committed to delivering consulting, placement, account management and claims solutions to clients who require specialist advice and support. Marsh JLT Specialty has bolstered Marsh’s leadership as a global specialty broker.

Corporate. Middle market clients are served by Marsh’s brokerage operations globally and constitute a substantial majority of clients served by Marsh & McLennan Agency (MMA) in the United States and large portions of Marsh’s international business.

• MMA** offers a broad range of commercial property and casualty products and services, as well as solutions for employee health and benefits, retirement and administration needs and a growing personal lines business in the United States and Canada. Since its first acquisition in 2009, MMA has acquired 82 agencies. MMA provides advice on insurance program structure and market dynamics, along with industry expertise and transactional capability.

Commercial & Consumer. Clients in this market segment typically face less complex risks and are served by Marsh’s innovative product and placement offerings and growing capabilities in digitally enabled distribution.

• Victor Insurance Holdings** is one of the largest underwriting managers of professional liability and specialty insurance programs worldwide. In the United States, Victor Insurance Managers (US) and ICAT Managers deliver risk management and insurance solutions to over 125,000 insureds through a national third-party distribution network of licensed brokers. Through Dovetail Managing General Agency, a small business platform, Victor Insurance Managers (US) deploys cloud-based technology to enable independent insurance agents, on behalf of their small business clients, to obtain online quotes from multiple insurance providers and bind property and casualty and workers compensation insurance policies in real time. Victor Insurance Managers (Canada), a leading managing general agent in Canada with over 43,000 insureds, delivers professional liability and construction insurance, as well as group and retiree benefits programs and claims handling for individuals, organizations and businesses. Victor has a growing business

in the UK (where it was formerly known as Bluefin Underwriting) and in Europe, where new businesses have been launched in the Netherlands, Italy and Germany.

• Marsh Affinity** focuses on insurance programs sold to insureds or vendors through a corporate sponsor using an affinity distribution model.

• High Net Worth (HNW)** Individual high net worth clients and family offices are serviced by MMA and other Marsh personal lines businesses globally. These businesses provide a single-source solution for high net worth clients and are dedicated to sourcing protections across a broad spectrum of risk. Using a consultative approach, Marsh's HNW practices analyze exposures and customizes programs to cover individual clients with complex asset portfolios.

Additional Services and Adjacent Businesses

In addition to insurance broking, Marsh provides certain other specialist advisory or placement services:

Marsh Advisory is a global practice comprising specialists who use data and analytics, including through Marsh’s Blue[i] digital analytics platform, to advise clients about exposures, critical business activities, and risk practices and strategies. Marsh Advisory provides client services in four main areas: Consulting Solutions, Analytics Solutions, Claims Solutions, and Captive Solutions.

Marsh Captive Solutions serves more than 1,350 captive facilities, including single-parent captives, reinsurance pools and risk retention groups. The Captive Solutions practice operates in 53 captive domiciles and leverages the consulting expertise within Marsh’s brokerage offices worldwide. The practice includes the Captive Advisory Group, a consulting arm that performs captive feasibility studies and helps to structure and implement captive solutions; the Captive Management Group, an industry leader in managing captive facilities and in providing administrative, consultative and insurance-related services; and the Actuarial Services Group, which is comprised of credentialed actuaries and supporting actuarial analysts.

Torrent Technologies is a service provider to Write Your Own (WYO) insurers participating in the National Flood Insurance Program (NFIP) in the United States. Torrent offers a comprehensive suite of both NFIP and private and excess flood insurance products and services to WYO companies and agents.

Bowring Marsh is an international placement broker primarily for property and casualty risks. Bowring Marsh uses placement expertise in major international insurance market hubs, including Bermuda, Brazil, China, United Arab Emirates, Ireland, Spain, United Kingdom, the United States, Singapore, Japan and Switzerland, and an integrated global network to secure advantageous terms and conditions for its clients throughout the world.

Services for Insurers

Insurer Consulting Group provides services to insurance carriers. Through Marsh's patented electronic platform, MarketConnect, and sophisticated data analysis, Marsh provides insurers with individualized preference setting and risk identification capabilities, as well as detailed performance data and metrics. Insurer consulting teams review performance metrics and preferences with insurers and provide customized consulting services to insurers designed to improve business planning and strategy implementation. Marsh's Insurer Consulting services are designed to improve the product offerings available to clients, assist insurers in identifying new opportunities and enhance insurers’ operational efficiency. The scope and nature of the services vary by insurer and by geography.

GUY CARPENTER

Guy Carpenter, the Company’s reinsurance intermediary and advisor, generated approximately 10% of the Company's total revenue in 2020. Currently, approximately 3,100 Guy Carpenter colleagues provide clients with a combination of specialized reinsurance broking expertise, strategic advisory services and analytics solutions. Guy Carpenter creates and executes reinsurance and risk management solutions for clients worldwide through risk assessment analytics, actuarial services, highly-specialized product knowledge and trading relationships with reinsurance markets. Client services also include contract and claims management and fiduciary accounting.

Acting as a broker or intermediary on all classes of reinsurance, Guy Carpenter places two main types of property casualty and life / health reinsurance: treaty reinsurance, which involves the transfer of a portfolio of risks; and facultative reinsurance, which involves the transfer of part or all of the coverage provided by a single insurance policy.

Guy Carpenter provides reinsurance services in a broad range of centers of excellence and segments, including: Automobile / Motor, Aviation, Crop/Agriculture, Cyber, D&O/Non-Medical Professional, Engineering / Construction, Environmental, GL & Umbrella, Health, Life, Marine and Energy, Medical Professional, Mortgage, Political Risk & Trade Credit, Program Manager Solutions, Property, Public Sector, Retrocessional Reinsurance, Surety, Terror, and Workers Compensation / Employer Liability.

Guy Carpenter also offers clients alternatives to traditional reinsurance, including industry loss warranties and, through its licensed affiliates, capital markets alternatives such as transferring catastrophe risk through the issuance of risk-linked securities. GC Securities, the Guy Carpenter division of MMC Securities LLC and MMC Securities (Europe) Limited, offers corporate finance solutions, including mergers & acquisitions and private debt and equity capital raising, and capital markets-based risk transfer solutions that complement Guy Carpenter's strong industry relationships, analytical capabilities and reinsurance expertise.

Guy Carpenter also provides its clients with reinsurance-related services, including actuarial, enterprise risk management, financial and regulatory consulting, portfolio analysis and advice on the efficient use of capital. Guy Carpenter's Global Strategic Advisory ("GSA") unit helps clients better understand and quantify the uncertainties inherent in their businesses. Working in close partnership with Guy Carpenter account executives, GSA specialists help support clients' critical decisions in numerous areas, including reinsurance utilization, catastrophe exposure portfolio management, new product and market development, rating agency, regulatory and account impacts, loss reserve risk, capital adequacy and return on capital.

Compensation for Services in Risk and Insurance Services

Marsh and Guy Carpenter are compensated for brokerage and consulting services through commissions and fees. Commission rates and fees vary in amount and can depend on a number of factors, including the type of insurance or reinsurance coverage provided, the particular insurer or reinsurer selected, and the capacity in which the broker acts and negotiates with clients. In addition to compensation from its clients, Marsh also receives other compensation, separate from retail fees and commissions, from insurance companies. This other compensation includes, among other things, payments for consulting and analytics services provided to insurers; compensation for administrative and other services (including fees for services provided to or on behalf of insurers relating to the administration and management of quota shares, panels and other facilities in which insurers participate); and contingent commissions, which are paid by insurers based on factors such as volume or profitability of Marsh's placements, primarily driven by MMA and parts of Marsh's international operations.

Marsh and Guy Carpenter receive interest income on certain funds (such as premiums and claims proceeds) held in a fiduciary capacity for others. For a more detailed discussion of revenue sources and factors affecting revenue in our Risk and Insurance Services segment, see Part II, Item 7 ("Management's Discussion and Analysis of Financial Condition and Results of Operations") of this report.

CONSULTING

The Company's Consulting segment generated approximately 40% of the Company's total revenue in 2020 and employs approximately 29,700 colleagues worldwide. The Company conducts business in this segment through Mercer and Oliver Wyman Group.

MERCER

Mercer delivers advice and digital solutions that help organizations meet the health, wealth and career needs of a changing workforce. Mercer has approximately 24,700 colleagues based in 43 countries. Clients include a majority of the companies in the Fortune 1000 and FTSE 100, as well as medium- and small-market organizations, public sector employees and individual customers. Mercer generated approximately 28% of the Company's total revenue in 2020.

Mercer operates in the following areas:

Health. Mercer assists public and private sector employers in the design and management of employee health care programs; administration of health benefits and flexible benefits programs, including benefits outsourcing; employee engagement with their health benefits through a digital experience; compliance with local benefits-related regulations; and the establishment of health and welfare benefits coverage for employees. Mercer provides a range of advice and solutions to clients, which, depending on the engagement, may include: total health and wellness management strategies; global health brokerage solutions; vendor performance and audit; life and disability management; and measurement of healthcare provider performance. These services are provided through traditional fee-based consulting as well as commission-based brokerage services in connection with the selection of insurance companies and healthcare providers. Mercer provides solutions for private active and retiree exchanges in the United States, as well as tools to enhance employee engagement with their health benefits through its DarwinSM platform across the world.

Mercer also provides consulting and actuarial services to U.S. state governments to support the purchase of healthcare through state Medicaid programs. In addition, Mercer provides consulting services to insurance carriers to assist them with improving product offerings available to clients, identifying new opportunities and enhancing insurers’ operational efficiency.

Outside of the U.S., Mercer and Marsh go to market together for Health benefits brokerage and consulting under the Mercer Marsh BenefitsSM (MMB) brand.

Wealth. Through its Wealth business, Mercer assists clients worldwide in the design, governance and risk management of defined benefit, defined contribution and hybrid retirement plans. Mercer provides actuarial consulting, investment consulting, investment management and related services to the sponsors and trustees of pension plans, master trusts, foundations, endowments, and insurance companies as well as wealth management and other financial intermediary firms. Mercer also provides retirement plan outsourcing, including administration and delivery of defined benefit and defined contribution retirement benefits.

Mercer's investment consulting and investment management services (also referred to as “investment solutions,” “delegated solutions,” “fiduciary management” or “outsourced Chief Investment Officer (OCIO) services”) cover a range of stages of the investment process, from strategy, asset allocation and implementation to ongoing portfolio management services. Mercer provides these services primarily to institutional and other sophisticated investors including retirement plans (e.g., defined benefit and defined contribution), master trusts, endowments and foundations and wealth managers and other financial intermediary firms, primarily through manager of manager funds sponsored and managed by Mercer. As of December 31, 2020, Mercer and its global affiliates had assets under management of approximately $357 billion worldwide.

Mercer also provides miscellaneous services to individual retail clients, including financial planning, high net worth risk solutions and other discretionary investment services.

Career. Mercer advises organizations on the engagement, skill assessment, management and reward of employees; the design of executive remuneration programs; people strategies during business transformation; improvement of human resource (HR) effectiveness; and the implementation of digital and cloud-based Human Resource Information Systems. In addition, through proprietary survey data and

decision support tools, Mercer provides clients with human capital information and analytical capabilities to improve strategic human capital decision making. Mercer helps clients plan and implement HR programs and other organizational changes designed to maximize employee engagement, drive desired employee behaviors and achieve improvements in business performance.

OLIVER WYMAN GROUP

With more than 5,000 professionals and offices in 31 countries, Oliver Wyman Group delivers advisory services to clients through three operating units, each of which is a leader in its field: Oliver Wyman, Lippincott and NERA Economic Consulting. Oliver Wyman Group generated approximately 12% of the Company's total revenue in 2020.

Oliver Wyman is a global leader in management consulting. Oliver Wyman combines deep industry knowledge with specialized expertise in strategy, operations, risk management and organization transformation. Industry groups include:

• Automotive

• Aviation, Aerospace & Defense

• Business Services

• Communications, Media & Technology

• Distribution & Wholesale

• Education

• Energy

• Financial Services (including corporate and institutional banking, insurance, wealth and asset management, public policy, and retail and business banking)

• Health & Life Sciences

• Industrial Products

• Public Sector

• Retail & Consumer Products

• Surface Transportation

• Travel & Leisure

Oliver Wyman overlays its industry knowledge with expertise in the following functional specializations:

• Actuarial. Oliver Wyman’s Actuarial Practice uses mathematical and statistical modeling skills and qualitative assessment methodologies to assist clients in evaluating and addressing risk.

• Climate and Sustainability. Oliver Wyman assists clients in cutting through complex climate systems and solving for operational efficiencies. Oliver Wyman helps clients discover new business opportunities, create new pathways, and respond to climate risk, to make needed changes commercially compelling.

• Corporate Finance & Restructuring. Oliver Wyman provides an array of capabilities to support investment decision making by private equity funds, hedge funds, sovereign wealth funds, investment banks, commercial banks, arrangers, strategic investors and insurers.

• Digital. Oliver Wyman partners with clients to address their digital challenges, blending the power of digital with deep industry expertise. By building strong capabilities and culture, Oliver Wyman accelerates and embeds digital transformation, working collaboratively with clients’ leaders, employees, stakeholders, and customers to jointly define, design, and achieve lasting results.

• Operations. Oliver Wyman helps organizations leverage their operations for a competitive advantage using a comprehensive set of capabilities, including performance improvement, digital operations strategy, and risk management.

• Organizational Effectiveness. Oliver Wyman's Organizational Effectiveness capability brings together deep functional expertise and industry knowledge to enable the whole organization to work in service of its strategic vision and to address the most pressing organizational, people, and change issues.

*•*Payments. Oliver Wyman draws on years of industry-shaping work in the Financial Services and Retail industries, deep digital expertise, and renowned research partners in its Celent® business, to help clients - from banks/issuers, to payments providers, to retailers - to build growth strategies, form effective partnerships, optimize costs, and manage risk.

• Pricing, Sales, and Marketing. Oliver Wyman helps organizations drive top-line and margin growth through outstanding strategy and decision making on pricing, marketing optimization, and best practices on sales effectiveness.

• Risk Management. Oliver Wyman works with chief financial officers, chief risk officers, and other senior finance and risk management executives of corporations and financial institutions on risk management solutions. Oliver Wyman provides effective, customized solutions to the challenges presented by the evolving roles, needs and priorities of these individuals and organizations.

• Strategy. Oliver Wyman is a leading provider of corporate strategy advice and solutions in the areas of growth strategy and corporate portfolio; non-organic growth and M&A; performance improvement; business design and innovation; corporate center and shared services; and strategic planning.

Lippincott is a creative consultancy specializing in brand and innovation that shapes recognized brands and experiences for clients globally. Lippincott's designers have helped create some of the world's most recognized brands.

NERA Economic Consulting provides economic analysis and advice to public and private entities to achieve practical solutions to highly complex business and legal issues arising from competition, regulation, public policy, strategy, finance and litigation. NERA professionals operate worldwide assisting clients including corporations, governments, law firms, regulatory agencies, trade associations, and international agencies. NERA's specialized practice areas include: antitrust; securities; complex commercial litigation; energy; environmental economics; network industries; intellectual property; product liability and mass torts; and transfer pricing.

Compensation for Services in Consulting

Mercer and Oliver Wyman Group are compensated for advice and services primarily through fees paid by clients. In the majority of cases, Mercer's Health business is also compensated through commissions for the placement of insurance contracts and supplemental compensation from insurers based on such factors as volume, growth of accounts, and total retention of accounts placed by Mercer. Mercer may receive commissions in other parts of its business, such as its Private Client Services business and certain financial advice businesses. Mercer's investments business and certain of Mercer's administration services are compensated typically through fees based on assets under administration or management or fee per member. For a majority of the Mercer-managed investment funds, revenue received from Mercer's investment management clients as sub-advisor fees is reported in accordance with U.S. GAAP, on a gross basis rather than a net basis. For a more detailed discussion of revenue sources and factors affecting revenue in the Consulting segment, see Part II, Item 7 ("Management's Discussion and Analysis of Financial Condition and Results of Operations") of this report.

REGULATION

The Company's activities are subject to licensing requirements and extensive regulation under U.S. federal and state laws, as well as laws of other countries in which the Company's subsidiaries operate. Across most jurisdictions we are also subject to various data privacy laws and regulations that apply to personal information belonging to our clients, their employees and third parties, as well as our own colleagues. In addition, we are subject to various financial crime laws and regulations through our activities, activities of associated persons, the products and services we provide and our business and client relationships. Such laws and regulations relate to, among other areas, sanctions and export control, anti-bribery, anti-corruption, anti-money-laundering and counter-terrorist financing. See Part I, Item 1A

("Risk Factors") below for a discussion of how actions by regulatory authorities or changes in legislation and regulation in the jurisdictions in which we operate may have an adverse effect on our businesses.

Risk and Insurance Services**.** While laws and regulations vary from location to location, every state of the United States and most foreign jurisdictions require insurance market intermediaries and related service providers (such as insurance brokers, agents and consultants, reinsurance brokers and managing general agents) to hold an individual or company license from a government agency or self-regulatory organization. Some jurisdictions issue licenses only to individual residents or locally-owned business entities; in those instances, if the Company has no licensed subsidiary, it may maintain arrangements with residents or business entities licensed to act in such jurisdiction. Such arrangements are subject to an internal review and approval process. Licensing of reinsurance intermediaries is generally less rigorous compared to that of insurance brokers, and most jurisdictions require only corporate reinsurance intermediary licenses.

In 2005, the Insurance Mediation Directive which, as from October 1, 2018 has been superseded by the Insurance Distribution Directive, was adopted by the United Kingdom and 27 other European Union Member States. Its implementation gave powers to the Financial Services Authority ("FSA"), the United Kingdom regulator at the time, to expand its responsibilities in line with the Financial Services and Markets Act (2000), the result of which was the regulation of insurance and reinsurance intermediaries. The enhanced regulatory regime implemented in the United Kingdom created a licensing system based on an assessment of factors which included professional competence, financial capacity and the requirement to hold professional indemnity insurance. In April 2013, the FSA was superseded by the Financial Conduct Authority ("FCA"). In April 2014, the FCA’s responsibilities were expanded further to include the regulation of credit activities for consumers. This included the broking of premium finance to consumers who wished to spread the cost of their insurance. In April 2015, the FCA obtained concurrent competition powers enabling it to enforce prohibitions on anti-competitive behavior in relation to financial services.

Insurance authorities in the United States and certain other jurisdictions in which the Company's subsidiaries do business, including the FCA in the United Kingdom, also have enacted laws and regulations governing the investment of funds, such as premiums and claims proceeds, held in a fiduciary capacity for others. These laws and regulations typically provide for segregation of these fiduciary funds and limit the types of investments that may be made with them, and generally apply to both the insurance and reinsurance business.

Certain of the Company's Risk and Insurance Services activities are governed by other regulatory bodies, such as investment, securities and futures licensing authorities. In the United States, Marsh and Guy Carpenter use the services of MMC Securities LLC, a SEC registered broker-dealer and introducing broker in the United States. MMC Securities LLC is a member of the Financial Industry Regulatory Authority ("FINRA"), the National Futures Association and the Securities Investor Protection Corporation ("SIPC"), primarily in connection with capital markets and other investment banking-related services relating to insurance-linked and alternative risk financing transactions. Also in the United States, Marsh uses the services of MMA Securities LLC, a SEC registered broker-dealer, investment adviser and member of FINRA and SIPC JSL Securities, Inc., a SEC registered broker-dealer and member of FINRA, SIPC and the Municipal Securities Rulemaking Board and Centurion Asset Management LLC, a SEC registered investment adviser, primarily in connection with retirement, executive compensation and benefits consulting and advisory services to qualified and non-qualified benefits plans, companies and executives and personal wealth management. In the United Kingdom, Marsh and Guy Carpenter use the expertise of MMC Securities (Europe) Limited, which is authorized and regulated by the FCA to provide advice on securities and investments, including mergers & acquisitions in the European Union. MMC Securities LLC, MMC Securities (Europe) Limited, MMA Securities LLC, JSL Securities, Inc. and Centurion Asset Management LLC are indirect, wholly-owned subsidiaries of Marsh & McLennan Companies, Inc.

Consulting*.* Mercer's retirement-related consulting and investment services are subject to pension law and financial regulation in many countries. Depending on the country, Mercer may rely on licensed colleagues or registered legal entities to engage in these services, or may utilize other MMC entities or external third parties. In addition, trustee services, investment services (including advice to persons, institutions and other entities on the investment of pension assets and assumption of discretionary

investment management responsibilities) and retirement and employee benefit program administrative services provided by Mercer and its subsidiaries and affiliates are also subject to investment and securities regulations in various jurisdictions, including regulations imposed or enforced by the SEC and the Department of Labor in the United States, the FCA in the United Kingdom, the Central Bank of Ireland and the Australian Prudential Regulation Authority and the Australian Securities and Investments Commission. In the United States, Mercer provides investment services through Mercer Investments LLC, (formerly Mercer Investment Management, Inc.), an SEC-registered investment adviser, which consolidated the activities of each of Mercer’s affiliated investment adviser entities in the United States (including Mercer Investment Consulting LLC and Pavilion Advisory Group) in 2019. Mercer Trust Company, a limited purpose New Hampshire chartered trust bank, may also provide services for certain clients of Mercer’s investment management business in the United States. The benefits insurance consulting and brokerage services provided by Mercer and its subsidiaries and affiliates are subject to the same licensing requirements and regulatory oversight as the insurance market intermediaries described above regarding our Risk and Insurance Services businesses. Mercer provides annuity buy-out support that is subject to regulations (for example, in the U.S., state insurance licensing regulations and ERISA). Mercer uses the services of MMC Securities LLC to provide certain services, including executive benefit and compensation services and securities dealing services.

FATCA**.** Regulations promulgated by the U.S. Treasury Department pursuant to the Foreign Account Tax Compliance Act and related legislation (FATCA) require the Company to take various measures relating to non-U.S. funds, transactions and accounts. The regulations impose on Mercer certain client financial account tracking and disclosure obligations with respect to non-U.S. financial institution and insurance clients.

COMPETITIVE CONDITIONS

The Company faces significant competition in all of its businesses from providers of similar products and services, including competition with regard to identifying and pursuing acquisition candidates. The Company also encounters strong competition throughout its businesses from both public corporations and private firms in attracting and retaining qualified employees. As the Company has clients across various geographies, industries and scale, the competitive landscape is complex and varies across these numerous markets. In addition to the discussion below, see "Risks Relating to the Company Generally — Competitive Risks," in Part I, Item 1A of this report.

Risk and Insurance Services**.** The Company's combined insurance and reinsurance services businesses are global in scope. Our insurance and reinsurance businesses compete principally on sophistication, range, quality and cost of the services and products they offer to clients. The Company encounters strong competition from other insurance and reinsurance brokerage firms that operate on a global, regional, national or local scale, from a large number of regional and local firms in the United States, the United Kingdom, the European Union and elsewhere, from insurance and reinsurance companies that market, distribute and service their insurance and reinsurance products without the assistance of brokers or agents and from other businesses, including commercial and investment banks, accounting firms, consultants and online platforms, that provide risk-related services and products or alternatives to traditional insurance brokerage services. In addition, third party capital providers have entered the insurance and reinsurance risk transfer market offering products and capital directly to the Company’s clients. Their presence in the market increases the competitive pressures that the Company faces.

Certain insureds and groups of insureds have established programs of self-insurance (including captive insurance companies) as a supplement or alternative to traditional third-party insurance, thereby reducing in some cases their need for third-party insurance placements. Certain insureds also obtain coverage directly from insurance providers. There are also many other providers of managing general agency, affinity programs and private client services, including specialized firms, insurance companies and other institutions.

Consulting**.** The Company's consulting businesses face strong competition from other privately and publicly held worldwide and national companies, as well as regional and local firms. These businesses generally compete on the basis of the range, quality and cost of the services and products they provide to clients. Competitors include independent consulting and outsourcing firms, as well as consulting and

outsourcing operations affiliated with accounting, information systems, technology and financial services firms. Mercer's investments business faces competition from many sources, including investment consulting firms (many of which offer delegated services), investment management firms and other financial institutions. In some cases, clients have the option of handling the services provided by Mercer and Oliver Wyman Group internally, without assistance from outside advisors.

Segmentation of Activity by Type of Service and Geographic Area of Operation.

Financial information relating to the types of services provided by the Company and the geographic areas of its operations is incorporated herein by reference to Note 17 to the consolidated financial statements included under Part II, Item 8 of this report.

HUMAN CAPITAL

As a professional services firm, we believe the health of our business relies on the strength of our workforce. Our shared purpose is to make a difference in moments that matter, helping clients meet the challenges of our time. Measurement of our talent outcomes are, therefore, not just a human capital priority, but a business imperative.

For detailed information regarding our human capital management, we encourage investors to visit https://www.mmc.com/about/esg.html for our consolidated environmental, social and governance ("ESG") report to be published in the first quarter 2021. The information on this website, and in the ESG report, does not constitute, and should not be viewed as, incorporation by reference of the information contained on, or available through, the website or the report and does not form part of this Form 10-K.

Our People. As of December 31, 2020, the Company and its consolidated subsidiaries employed 76,000 colleagues worldwide, including approximately 44,100 in Risk and Insurance Services and 29,700 in Consulting. Two-thirds of our global workforce are located in either North America or Europe. While these remain our largest work regions, we have also grown our presence in Asia-Pacific and the Middle East over the last several years. Women comprise more than half of our global enterprise workforce, and approximately 30% of our senior leaders are women. In the United States, where we have the most complete data through workforce self-identification of race and ethnicity, approximately 1 in 4 U.S. colleagues and 14% of U.S. senior leaders identify as non-White.

Our Governance. The Chief People Officer is responsible for developing and executing our enterprise people strategy. This includes the attraction, recruitment, hiring, development and engagement of talent to deliver on our strategy and the design of colleague total rewards programs. The Chief People Officer and the Chief Inclusion & Diversity Officer are responsible for developing and integrating our diversity and inclusion approach into our strategy.

Our ESG Committee and Compensation Committee of the board of directors have oversight of these initiatives. The Compensation Committee has responsibility to review certain key human resource strategic activities, including those relating to diversity, training and recruitment. The Compensation Committee coordinates with the ESG Committee on diversity initiatives and both committees receive reports at least annually on diversity and inclusion from the Company’s Chief People Officer. The Chief Executive Officer and Chief People Officer regularly update our board of directors, the ESG Committee and the Compensation Committee on the Company’s human capital trends and activities.

Diversity & Inclusion. Our Company’s greatest strength is the collective talent of our people. We believe the more diverse our backgrounds and experiences, the more we can achieve together working side by side. We seek capable, creative and fair-minded people who can help us enable client success, find smarter ways to do things and live our Code of Conduct, The Greater Good. We believe that inclusion means more than acceptance—it means belonging. Over the last year, we have taken several concrete actions to further goals, including the formation of a Race Advisory Council to advise our Executive Committee and help amplify diverse perspectives in decision-making. Other initiatives included the design of a new learning and sponsorship program to help underrepresented colleagues strengthen leadership skills, as well as the creation of various forums and networks to promote ongoing candid conversations within the organization.

Talent Development. We strive to create an environment where individuals and teams can perform to their highest potential and where career growth and mobility are encouraged and supported. We are committed to helping colleagues perform at their best by encouraging regular discussions about their

goals, performance, career aspirations and development opportunities. We also recognize the importance of our 13,000 people managers in their crucial roles for reviewing our talent pipeline and have given them increased support and opportunities for promoting the professional and personal growth of their teams. In addition, we offer more than 16,000 individual learning courses as part of continuous learning to help our colleagues grow and develop. In 2020, we published a set of People Manager Practices, centered around managing inclusively, that define what effective people management looks like. Managers also have access to our dedicated People Manager Hub, a one-stop source of information and community for all people managers globally.

Colleague Engagement. Each year we ask our colleagues to share their views on working at Marsh & McLennan through a company-wide engagement survey. Developed internally by our Global Talent Development team, the survey methodology has been consistent since 2011, with updates to specific questions as necessary. A third-party administers our survey in order to maintain confidentiality of responses. In 2020, a record number of colleagues completed the survey. As in the past, we continue to use the survey responses to help inform the ongoing development of a vibrant and inclusive culture.

Health and Wellbeing. As a company, our success depends on the health and wellbeing of our colleagues—we want to support our colleagues with resources, protection and peace of mind to live healthy lives. We offer comprehensive health insurance, including medical coverage and other core health benefits based on the market. We also prioritize our colleagues’ mental wellness, including 24/7 access to an Employee Assistance Program for confidential counselling on personal issues for over 80 percent of our colleagues and their eligible family members, and critical incident support in countries where a disaster has occurred. In addition, we offer competitive time-off benefits, including a paid day off each year to volunteer.

Supporting our colleagues as they navigate the unprecedented challenges of COVID-19 has been our highest priority in 2020 and our teams have responded by working in innovative ways. Refer to "Recent Developments" included in Item 7, "Management’s Discussion and Analysis of Financial Condition and Results of Operations" for information on our response to the COVID-19 pandemic.

Total Rewards. We recognize how important it is to be financially secure through employment, so we offer competitive rewards to help build colleagues’ personal wealth and improve their financial wellbeing. Base pay is just the start. Through our annual bonus program, we encourage performance that aligns with the Company’s interests by providing eligible colleagues with discretionary awards. We also offer various incentives in certain circumstances, such as sales incentives and long-term incentives to roles that have a significant impact on our long-term performance designed to foster the Company’s long-term success. Our robust offerings also include retirement benefits, savings and stock investment plans in certain jurisdictions.

EXECUTIVE OFFICERS OF THE COMPANY

The executive officers and executive officer appointees of the Company are appointed annually by the Company’s Board of Directors. The following individuals are the executive officers of the Company:

Peter J. Beshar, age 59, is Executive Vice President and General Counsel of Marsh & McLennan Companies. In addition to managing the Company’s Legal, Compliance & Public Affairs groups, Mr. Beshar also oversees the Company’s Risk Management group. Before joining Marsh & McLennan Companies in November 2004, Mr. Beshar was a Litigation Partner in the law firm of Gibson, Dunn & Crutcher LLP. Mr. Beshar joined Gibson, Dunn & Crutcher in 1995 after serving as the Assistant Attorney General in charge of the New York Attorney General's Task Force on Illegal Firearms and as the Special Assistant to former U.S. Secretary of State Cyrus Vance in connection with the peace negotiations in the former Yugoslavia.

Paul Beswick, age 46, is Senior Vice President and Global Chief Information Officer (CIO) of Marsh & McLennan Companies. In this role, he manages over 5,000 technologists supporting Marsh & McLennan’s global businesses. Prior to his appointment as Marsh & McLennan CIO in January 2021, Mr. Beswick was a Partner and Global Head of Oliver Wyman Labs and the Digital Practice at Oliver Wyman. During more than two decades with Oliver Wyman, he worked in various sectors, including retail, transportation, telecom, and consumer goods. Before this, Mr. Beswick headed Oliver Wyman's North American Retail Practice. Mr. Beswick holds an MA (first class) in chemical engineering from Cambridge University.

Dominic Burke, age 62, is Vice Chair of Marsh & McLennan Companies. He joined the firm in 2019 with the acquisition of Jardine Lloyd Thompson Group (JLT), after having served as JLT’s Group Chief Executive for more than 13 years. He also serves as Chairman of Marsh JLT Specialty. Mr. Burke has more than three decades of experience in the insurance industry. Prior to serving as JLT’s Group Chief Executive, Mr. Burke held various roles at JLT including Group Chief Operating Officer and prior to that, CEO of JLT’s U.K. Retail and Employee Benefits business. Mr. Burke joined JLT in 2000, when it acquired the company he founded, Burke Ford Insurance Group. Mr. Burke serves as the Chairman of Newbury Racecourse plc and is a Director for the charity Injured Jockeys Fund in the U.K.

John Q. Doyle, age 57, is Vice Chair, Marsh & McLennan Companies and President and Chief Executive Officer of Marsh. He oversees all of Marsh’s businesses and operations globally. Mr. Doyle was named CEO of Marsh in July 2017, having joined Marsh & McLennan Companies as President of Marsh in April 2016. Prior to that, he was Chief Executive Officer of AIG’s commercial insurance businesses. Mr. Doyle began his career at AIG in 1986 and held several senior executive positions, including President and Chief Executive Officer of AIG property and casualty in the U.S., President and Chief Executive Officer of National Union Fire Insurance Company, and President of American Home Assurance Company.

Martine Ferland, age 59, is Vice Chair, Marsh & McLennan Companies and President and Chief Executive Officer of Mercer, a role she assumed in March 2019. Previously, she was Mercer’s Group President, responsible for leading the firm’s regions and Global Business Solutions. She joined Mercer in 2011 as Retirement Business Leader for the Europe and Pacific region, and has served as Europe and Pacific Region President and Co-President, Global Health. Ms. Ferland began her career as a pension actuary and consultant at Willis Towers Watson, where she spent 25 years and held various leadership positions in Montreal and New York. Ms. Ferland is a Fellow of the Society of Actuaries and of the Canadian Institute of Actuaries.

Carmen Fernandez, age 47, is Senior Vice President and Chief People Officer for Marsh & McLennan Companies. Prior to her current role, Ms. Fernandez held positions within Marsh & McLennan for 15 years, most recently Deputy CHRO, CHRO of Guy Carpenter, and HR leadership roles at Mercer, including North America HR Leader, Global HR Leader for the Career business and Chief of Staff in the Office of the CEO. Before joining Marsh & McLennan, Ms. Fernandez worked in investment banking at Bank of America and Goldman Sachs. She began her career as a consultant with Pricewaterhouse Coopers.

Daniel S. Glaser, age 60, is President and Chief Executive Officer of Marsh & McLennan Companies. Prior to starting his current role in January 2013, Mr. Glaser served as Group President and Chief Operating Officer of the Company. He rejoined Marsh & McLennan Companies in December 2007 as Chairman and Chief Executive Officer of Marsh, returning to the firm where he had begun his career right out of university in 1982. Mr. Glaser is an insurance industry veteran who has held senior positions in commercial insurance and insurance brokerage, working in the United States, Europe and the Middle East. Mr. Glaser serves as the Chairman of the U.S. Federal Advisory Committee on Insurance (FACI). He is a member of: the Board of Trustees for The Institutes and the Board of Directors for the Partnership for New York City. He is also Co-Chair of the International Advisory Board for BritishAmerican Business.

Peter Hearn, age 65, is Vice Chair, Marsh & McLennan Companies and President and Chief Executive Officer of Guy Carpenter. Previously, he was Global Chairman of Willis Re from March 2011 to June 2015. Prior to that, Mr. Hearn served as the company’s Global CEO from February 2005 to March 2011, during which time he was also a member of the Willis Group Executive Committee. Mr. Hearn began his reinsurance career in 1978 with Willis Faber and Dumas, working in the North American casualty, facultative, marine, and North American reinsurance divisions until 1981, when he joined Towers Perrin Forster and Crosby. Mr. Hearn joined Willis Re as a Senior Vice President in 1994.

Scott McDonald, age 54, is Vice Chair, Marsh & McLennan Companies and President and Chief Executive Officer of Oliver Wyman Group. Prior to assuming this role in January 2014, Mr. McDonald was President of Oliver Wyman. Before becoming President of Oliver Wyman in 2012, Mr. McDonald was the Managing Partner of Oliver Wyman's Financial Services practice and has held a number of senior positions, including the Global head of the Corporate & Institutional Banking Practice. Before joining Oliver Wyman in 1995, he was an M&A investment banker with RBC Dominion Securities in Toronto.

Mark McGivney, age 53, is Chief Financial Officer of Marsh & McLennan Companies. Prior to assuming this role in January 2016, Mr. McGivney held a number of senior financial management positions since joining the Company in 2007. Most recently he was Senior Vice President, Corporate Finance of Marsh & McLennan, and was responsible for leading and directing the Company’s Corporate Development, Treasury and Investor Relations functions from 2014 until 2016. Prior to that, he served as Chief Financial Officer of Marsh, and Chief Financial Officer and Chief Operating Officer of Mercer. His prior experience includes senior positions at The Hanover Insurance Group, including serving as Senior Vice President of Finance, Treasurer, and Chief Financial Officer of the Property & Casualty business, as well as positions with Merrill Lynch and Price Waterhouse.

AVAILABLE INFORMATION

The Company is subject to the information reporting requirements of the Securities Exchange Act of 1934. In accordance with the Exchange Act, the Company files with, or furnishes to, the SEC its annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and proxy statement for its annual shareholders' meeting. The Company makes these reports and any amendments to these reports available free of charge through its website, www.mmc.com, as soon as reasonably practicable after they are filed with or furnished to the SEC. The SEC also maintains a website at www.sec.gov that contains reports, proxy and information statements and other information regarding issuers, like the Company, that file electronically with the SEC.

The Company also posts on its website certain governance and other information for investors.

The Company encourages investors to visit these websites from time to time, as information is updated and new information is posted. Website references in this report are provided as a convenience and do not constitute, and should not be viewed as, incorporation by reference of the information contained on, or available through, the websites. Therefore, such information should not be considered part of this report.