Situational Awareness, a hedge fund focused on artificial intelligence and founded by former OpenAI researcher Leopold Aschenbrenner, sold most of its publicly traded stocks to Ken Griffin's Citadel, as first reported by The Wall Street Journal on July 30, 2026 and subsequently detailed by TechCrunch. The fund kept its shares in Anthropic, an AI company that is privately owned and not traded on the stock market.

The sale is a sharp turnaround for a fund that, per the Financial Times, returned 439% for the year through June. CNBC had reported that Situational Awareness managed as much as $45 billion at its peak. After Citadel took on the bulk of the public holdings, Bloomberg estimated the fund's assets at roughly $10 billion, down from around $20 billion in recent months according to an earlier WSJ report.

The losses were made worse by leverage, which is when a fund borrows money to make bigger bets. The stocks that suffered the most included SK Hynix, SanDisk, Bloom Energy, and Nebius Group, each falling more than 30% in a single month. A March 2026 Forbes article noted that the fund was betting on power plants and data centers rather than AI software companies directly.

Six days before the Citadel sale became public, Aschenbrenner was already asking investors to stay. On July 24, 2026, he wrote a letter, seen by the Financial Times, calling the selloff one of the best buying opportunities since early last year and inviting clients to add more money starting August 1. Bloomberg reported that the appeal did not get the response he was hoping for.

Aschenbrenner is 25, German-born, and had no trading experience before starting the fund in 2024. He joined OpenAI in 2023 to work on a team focused on keeping advanced AI safe, and was let go about a year later for what OpenAI said was sharing internal information. The fund's early investors included Jane Street, a major trading firm; Patrick and John Collison, the brothers who co-founded the payments company Stripe; and Meta executives Daniel Gross and Nat Friedman.

Government filings show the fund was also placing bets beyond the stock market. Situational Awareness LP, a Delaware limited partnership (CIK 0002045724, EIN 992901544, fiscal year ending December 31), filed a Form 13F-HR on May 15, 2026 for the quarterly period ending March 31, 2026, listing its address at 512 2nd Street, Suite 400. A Schedule 13G filed May 20, 2026 identifies the firm as an adviser connected to an entity called "SAF AI." A separate Schedule 13G filed June 17, 2026 lists "Situational Awareness Partners LP" as a reporting person. And as of April 14, 2026, TechCrunch reported that a data center startup called Fluidstack was in talks for a $1 billion funding round led by Situational Awareness at an $18 billion valuation.

Keeping the Anthropic shares is the detail that stands out. The public stocks, which focused on the physical side of AI, like memory chips, energy, and data centers, took the hit from the selloff and the borrowed money on top. The Anthropic stake, which is private and cannot be sold quickly, was not part of what Citadel bought. Whether that holding goes up or down in value will likely decide whether Aschenbrenner's fund recovers or keeps shrinking.

The broader pattern here is worth noting. Funds built around one person's confidence, especially someone with no track record of trading, tend to swing hard in both directions. The 439% return drew in large amounts of money; the losses that followed forced the fund to sell off borrowed positions in a bulk deal to one of the biggest trading firms in the world. The fact that Aschenbrenner's letter called the selloff a buying opportunity, and that investors reportedly did not respond strongly, suggests that at least some of them are pulling back rather than adding more.

The private holdings, including Anthropic, the possible Fluidstack investment, and the "SAF AI" entity, are the parts of the fund that cannot be sold in a single bulk trade. They are also the hardest to put a price on. For a fund that has gone from $45 billion to $10 billion in a short time, the gap between what it can sell quickly and what it cannot is where this story goes next.