The July gains came after Citadel acquired the bulk of the public-stock portfolio formerly held by Situational Awareness late last month.

When rival hedge funds face catastrophic losses, billionaire investor Ken Griffin has a habit of identifying opportunities and showing up with a checkbook. Citadel’s founder last…

Leopold Aschenbrenner's AI hedge fund Situational Awareness lost 67% in July, forcing a $16 billion portfolio sale to Citadel after margin calls.