- Oliver Wyman opens a new office in Manama.
- Oliver Wyman opens a new office in Bangkok.
- Oliver Wyman opens new offices in Abu Dhabi, Brussels, Ottawa, Perth, and Vienna.
- Oliver Wyman acquires Avascent, an Aerospace and Defense (A&D) management consulting firm.
- Oliver Wyman acquires Booz Allen Hamilton’s strategy consulting business serving the Middle East and North Africa.
- Oliver Wyman, as part of Marsh McLennan, announces its commitment to chart a path to net-zero across its operations by 2050 and reduce its emissions by 50 percent by 2030.
- Oliver Wyman acquires Azure Consulting, a premium boutique management consulting firm in Australia.
- Oliver Wyman acquires Huron’s global life sciences strategy consulting practice.
- Nick Studer is appointed as President and CEO of the Oliver Wyman Group and Deputy Chairman of Marsh McLennan.
- Opening of new offices in Raleigh and Melbourne
- Oliver Wyman becomes certified as a Carbon Neutral® company and sets in motion a long-term strategy to integrate sustainability into its operations and reduce emissions.
- Oliver Wyman opens a new office in Johannesburg.
- Oliver Wyman launches the Oliver Wyman Forum, a platform that strives to bring together business, public policy, and social enterprise leaders to help solve the world’s toughest problems.
- Oliver Wyman acquires AVISA, a UK based global market leader in aviation consultancy, training and airworthiness management.
- Oliver Wyman acquires LShift, an independent software development company with offices in the UK and Germany.
- Oliver Wyman acquires TeamSAI, an aviation consulting company with expertise in technical consulting, safety management and aircraft certification.
- Oliver Wyman acquires the business that formerly operated as OC&C Greater China, a management consulting firm focused on Retail and Consumer Goods sectors.
- Oliver Wyman acquires Bonfire, an employee engagement and internal communications agency.
- Oliver Wyman acquires the business that formerly operated as OC&C Boston, a boutique management consulting firm with strong capabilities in business media, information services, and education.
- Oliver Wyman acquires Corven, a boutique management consulting firm focused on Energy.
- Oliver Wyman unifies its global capabilities under a single operating model, integrating its industry practices closer together with the launch of five firmwide capability practices, known as "Horizontals."
- Oliver Wyman acquires ChapterHouse.
- Oliver Wyman acquires Academee (United Kingdom).
- Oliver Wyman acquires Hemeria (France).
- Oliver Wyman acquires Celent.
- Oliver Wyman acquires Harbour Consulting.
- Oliver Wyman officially launches as a unified brand and world-class management consulting firm, leveraging the united power of Mercer Oliver Wyman, Mercer Management Consulting, and Mercer Delta Organizational Consulting.
- Mercer MC acquires CAVOK International, Inc. (US).
- Mercer MC acquires DiamondCluster International's Continental Europe, Middle East, and South America operations.
- Mercer MC acquires MultiModal Applied Systems (US).
- Mercer Oliver Wyman forms its Strategic IT practice and a Corporate Risk Consulting group, including practice areas in Enterprise Risk, Actuarial, and Strategic Finance.
- Mercer Delta acquires CDR International, LLC (US).
- Mercer MC acquires c.r.m. Concord, s.a. (Spain).
- Mercer Oliver Wyman formed, following the acquisition of Oliver, Wyman & Company by Marsh & McLennan Companies, Inc.
- Mercer Delta acquires Change Management Consultants (France).
- Mercer Delta acquires Johnston Smith International, Inc. (Canada).
- Mercer MC acquires Informed Sources Holdings Ltd. (UK and US).
- Oliver, Wyman & Company acquires Intervaluenet (Italy).
- Delta Consulting Group acquired by Marsh & McLennan Companies, Inc.
- Mercer MC acquires Análisis y Desarrollo de Proyectos (Mexico).
- Mercer MC acquires St. Gallen Consulting Group (Germany and Switzerland).
- Mercer MC acquires Dr. Seebauer & Partner GmbH (Germany and Switzerland).
- Oliver, Wyman & Company acquires Higginson & Partners (UK).
- Mercer MC acquires Corporate Decisions, Inc. (US, UK, France).
- Oliver, Wyman & Company establishes presence in the Pacific Rim.
- Mercer MC acquires MID S.A. (France).
- Mercer MC acquires Unternehmensberatung Munchen GmbH (Germany and Switzerland).
- Temple, Barker & Sloane / Strategic Planning Associates name changed to Mercer Management Consulting, Inc.
- Merger of Temple, Barker & Sloane and Strategic Planning Associates.
- Strategic Planning Associates acquired by Marsh & McLennan Companies, Inc.
- Oliver, Wyman & Company creates a dedicated risk management practice that helps transform how financial institutions and major corporations manage risk.
- Oliver, Wyman & Company initiates expansion outside of the US with office openings in London and Toronto.
- Temple, Barker & Sloane acquired by Marsh & McLennan Companies, Inc.
- William M. Mercer acquires Duncan C. Fraser & Co and Future Cost Analysts, forming the initial basis of Oliver Wyman's Risk Finance and Insurance operations.
- Oliver, Wyman & Company founded in New York.
- Delta Consulting Group founded in New York.
- Strategic Planning Associates, Inc. founded in Washington, D.C.
- Temple, Barker & Sloane, Inc. founded in Boston.
- NERA Economic Consulting, Inc., or National Economic Research Associates, founded.
- American brand strategy and design firm Lippincott founded in New York City.