McKinsey & Company is an American worldwide management consulting firm, founded in 1926 by University of Chicago professor James O. McKinsey, that advises on strategic management to corporations, governments, and other organizations. Under the leadership of Marvin Bower, McKinsey expanded into Europe during the 1940s and 1950s. In the 1960s, McKinsey's Fred Gluck—along with Boston Consulting Group's Bruce Henderson, Bill Bain at Bain & Company, and Harvard Business School's Michael Porter—transformed corporate culture. A 1975 publication by McKinsey's John L. Neuman introduced the business practice of "overhead value analysis" that contributed to a downsizing trend that eliminated many jobs in middle management.McKinsey is the oldest and biggest of the "Big Three" management consultancies (MBB), it is seen as one of the most prestigious employers in the industry and has been recognized by Vault as the most prestigious consulting firm in the world.
McKinsey publishes a business magazine, the McKinsey Quarterly, and its consultants have authored many books. Its alumni have held high-level corporate and political positions. The firm has been associated with a number of notable scandals including the collapse of Enron in 2001 and the 2007–2008 financial crisis. It has also drawn controversy for involvement with Purdue Pharma, U.S. Immigration and Customs Enforcement and authoritarian regimes.