Founded in 1926, McKinsey is still widely considered the most prestigious consulting firm in the field. It reported more than $15 billion in revenue in 2022 and employs 45,000-plus people in 133 offices around the globe. McKinsey says it’s served more than 3,000 clients, including nearly every one of the world’s 100 largest corporations. Above: Culture warriors: McKinsey was hired to transform the culture at Rikers Island. Instead, consultants embraced the brutality of the prison.