Ken Griffin's Citadel has bought the entire public-equities portfolio of Situational Awareness, the AI-focused hedge fund founded by former OpenAI researcher Leopold Aschenbrenner, after the fund was forced to unwind its holdings amid steep losses and mounting margin pressure.
What Happened
Situational Awareness sold its entire book of public stock positions — both long and short — to Citadel in a single block trade before the market opened on July 30, 2026. The forced sale came after the fund sustained significant losses in recent weeks as its concentrated bets on AI infrastructure stocks like SK Hynix declined, while short positions in software companies such as Adobe moved sharply against it. The fund's prime brokers, including Bank of America, Goldman Sachs, and JPMorgan Chase, had been working with Situational Awareness to help it meet margin requirements or reduce positions in an orderly fashion. Millennium Management reportedly submitted a competing bid, though Citadel ultimately won the deal; the price and specific securities involved were not disclosed.
How Big the Fund Had Become
Situational Awareness had grown to as large as $45 billion at the start of July before the losses took hold. According to the Financial Times, the fund returned 439% net during the first half of 2026 before the July reversal — a run so dramatic that the subsequent unwind stands out even by hedge fund standards. Heavy use of leverage made the reversal considerably harder to absorb once the AI-linked positions began moving against the fund.
What the Fund Actually Held
Situational Awareness had built concentrated public positions across the AI supply chain, including stakes in CoreWeave, IREN, Core Scientific, Applied Digital, Bloom Energy, SK Hynix, Riot Platforms, and CleanSpark — largely companies tied to AI compute, data-center power, and semiconductors. That strategy delivered outsized gains for much of 2026 as investors assigned rapidly rising valuations to scarce power and data-center capacity, before the same concentrated exposure became the source of the fund's undoing once sentiment reversed.
A Defiant Letter Just Before the Collapse
Notably, in a July 24 investor letter — just six days before the forced sale — Aschenbrenner acknowledged the fund had "not been immune" to the sell-off, but characterized it as one of the best buying windows since early 2025, and opened a new capital-raising window for investors starting August 1. That optimistic framing preceded the margin-driven liquidation by less than a week.
What Stays With the Fund
Despite selling off its entire public portfolio, Situational Awareness retains its private-company holdings, the largest of which is a stake in Anthropic PBC valued by the Financial Times at roughly $5 billion. The firm intends to continue operating as a private investment vehicle going forward — essentially, as one outlet put it, an Anthropic holding company with a hedge fund attached. A spokesperson told CNBC that reports the fund was shopping its Anthropic stake were "not accurate." Aschenbrenner is engaged to Avital Balwit, chief of staff to Anthropic CEO Dario Amodei.
Why It Matters
The episode has been described by some market observers as a possible marker of forced-seller capitulation in the broader AI trade, following weeks of volatility in AI-linked stocks. Whether the removal of Situational Awareness as a forced seller signals that the technical pressure on AI infrastructure names has eased — as opposed to a more fundamental repricing of the sector — remains an open question analysts are watching closely in the trade's aftermath.
What's Next
With Citadel now digesting the bulk of Situational Awareness's former public holdings, market watchers will be tracking whether implied volatility in AI-infrastructure-linked names normalizes now that the forced seller is gone. Aschenbrenner's fund, meanwhile, moves forward as a smaller, privately focused vehicle anchored by its Anthropic stake, following one of the more dramatic hedge fund reversals of the year.