The book “The Almost Classified Guide to CIA Front Companies, Proprietaries & Contractors” lists McKinsey & Company.
They state that John Brennan was closely associated with them.
The Story McKinsey
Didn’t Want Written
Illustrations by Laura Lannes
https://www.institutionalinvestor.com/article/b1g5zjdcr97k2y/The-Story-McKinsey-Didn-t-Want-Written
Despite the concerns about the protocol, when the Westmoreland disclosures were filed on July 3 in accordance with it, McKinsey disclosed hundreds of MIO connections. They included 56 investments — in funds run by Whitebox, UBS, BlackRock, Oaktree Capital Management, PIMCO, and Bank of America, among others. It also disclosed numerous hedge funds that had been McKinsey clients when they were lenders to other companies that filed for bankruptcy.