Citadel snaps up $20B AI fund's portfolio after margin-call collapse

AI-focused hedge fund Situational Awareness sold its public stock portfolio to Citadel after margin calls forced liquidation of leveraged bets, marking a sudden collapse for the $20 billion firm led by former OpenAI researcher Leopold Aschenbrenner.

"This is what happens when a tech bro tries to play hedge fund manager," Hank Medina, founder of Litquidity, said on X. "He gets blown up by leverage and ripped to shreds by a seasoned financial juggernaut who strikes when there's blood in the water."

The fund, which had amassed over $20 billion in assets under management since its founding about two years ago, held leveraged positions in AI supply-chain names including memory-chip makers SK Hynix and Sandisk, fuel-cell maker Bloom Energy, and AI cloud provider Nebius Group. Shares in all of those companies plummeted over the past month as investors shed AI and technology stocks on worries about massive capital expenditures and higher borrowing costs. The fund was down 67 percent in July.

Citadel, with $71 billion in assets under management, purchased only the leveraged portion of the portfolio, while Situational retained assets funded by client capital and its private investments, including a stake in Anthropic. Millennium Management also bid on the portfolio. The forced liquidation raises questions about the durability of the AI trade as other leveraged funds face similar margin pressures.

Aschenbrenner, who is in his mid-20s, had no professional investing experience when he launched the firm with a few hundred million dollars. He rose to prominence with a 2024 essay, "Situational Awareness: The Decade Ahead," that foresaw the path of AI's development and attracted a cult-like following. His firm's regulatory filings were studied by other investors who tracked its movements.

Early backers included Stripe co-founders Patrick and John Collison, as well as Daniel Gross and Nat Friedman, who are both currently helping lead Meta Platforms' AI efforts. The fund also attracted institutional investors including quant trading firm Jane Street, which rarely allocates capital to outside managers.

A Familiar Pattern of Leverage and Downfall

The collapse echoes previous hedge fund blowups where a sound thesis didn't guarantee a winning trade. Business Insider's Alistair Barr compared the fund's implosion to Long-Term Capital Management and Peter Thiel's Clarium Capital. In Situational Awareness's case, the market turned on the fund, but that doesn't necessarily mean Aschenbrenner's ideas on AI infrastructure are wrong, Barr wrote.

One possible trigger: the sell-off of South Korean memory-chip stocks in June, which triggered margin calls and led to a vicious feedback loop that spread into other AI-related stocks owned by the fund.

Shay Boloor, chief market strategist at Futurum Equities, called it "the story of 2026." He noted that Citadel was pushing surprise-rate-hike fears just days before the AI trade collapsed, forcing the 4x-levered fund to unload its book near the lows. Citadel then reportedly bought most of those assets at significantly lower prices.

Michael Dempsey, managing partner at Compound, said in a post on X that Situational Awareness's "prescience was incredibly impressive and likely should still be funded and respected." But he added that "anyone who has experience in public markets could somewhat easily see this was One Big Trade and so probably there should have been way better views on risk besides buying index-level puts."

Shares of companies in Situational's portfolio rose Thursday after news of the stock sales surfaced, suggesting some relief that forced selling has concluded. But the episode may accelerate selling in AI and technology equities as other leveraged funds face similar margin pressures. The AI trade's fragility is now on display for every leveraged participant in the market, and the ripple effects could extend well beyond the fund's former holdings.

This article is for informational purposes only and does not constitute investment advice.