Citadel

Citadel is Ken Griffin's hedge fund, one of Wall Street's largest prime-brokerage clients alongside firms such as Millennium. In July 2026 it absorbed the roughly $16 billion public-equity book of Leopold Aschenbrenner's Situational Awareness at a discount understood to be near 10 percent, and has since unwound more than 80 percent of that risk in over 100 block trades worth more than $4 billion.