Citadel Buys $16 Billion in AI Stocks After a Hedge Fund Collapses

Citadel bought roughly $16 billion in stocks from Situational Awareness, an AI-focused hedge fund founded by former OpenAI researcher Leopold Aschenbrenner. The fund grew from $225 million at its 2024 launch to a $20 billion peak, returning 439% in early 2026. Then borrowed bets went sour, triggering margin calls — demands to repay loans immediately — and forced the fund to sell everything in July 2026.