From Wikipedia:
Under a financial disclosure filed by the Biden transition team in December 2020, Secretary of State nominee Antony Blinken declared that clients of WestExec included “investment giant Blackstone, Bank of America, Facebook, Uber, McKinsey & Company, the Japanese conglomerate SoftBank, the pharmaceutical company Gilead, the investment bank Lazard, Boeing, AT&T, the Royal Bank of Canada, LinkedIn and the venerable Sotheby’s”. In a similar form, National Security Advisor-designate Avril Haines disclosed that WestExec had worked with data-mining company Palantir Technologies.
https://en.wikipedia.org/wiki/WestExec_Advisors