AI hedge fund Situational Awareness forced to sell $16 billion portfolio to Citadel after chip bets backfire
The fund run by 24-year-old Leopold Aschenbrenner was hit by July's semiconductor sell-off and margin calls, leading to an overnight auction where Ken Griffin's Citadel bought the bulk of the portfolio at a discount.
Leopold Aschenbrenner, the 24-year-old German founder of hedge fund Situational Awareness, has been forced to sell the vast majority of his fund's holdings after leveraged bets on AI infrastructure and chip stocks turned sharply against him in July 2026. The fire sale, one of the largest rushed equity transactions in Wall Street history, saw Ken Griffin's Citadel acquire a portfolio valued at roughly $16 billion at a discount of more than 10%.
The rise of a 'K-Nostradamus'
Aschenbrenner's ascent was meteoric. Having studied economics, mathematics and statistics at Columbia University, he joined OpenAI where he worked on controlling future superhuman AI models. After being dismissed from OpenAI in spring 2024 for what the company described as leaking trade secrets, he authored a 165-page essay titled "Situational Awareness" which predicted AI would transform society faster than widely expected. The essay became the blueprint for his hedge fund, launched with no prior finance industry experience. Within two years, assets under management ballooned from a few hundred million dollars to $45 billion at its peak, according to CNBC and the Wall Street Journal. By late June 2026, Aschenbrenner reported to investors that the fund had returned more than 400% since the start of the year.
Leverage and a two-front squeeze
Behind the returns lay extreme leverage. CNBC reported that Situational Awareness deployed roughly four times more borrowed money than its own capital. The fund took concentrated long positions in semiconductor firms like South Korea's SK Hynix and other AI infrastructure plays, while simultaneously shorting software companies it believed would be disrupted by AI. In July the strategy unwound on both fronts. A report suggesting a Chinese technological leap in chip manufacturing equipment and a Wall Street Journal story about Nvidia planning around $250 billion in guarantees for OpenAI triggered a sharp sell-off in chip stocks. SK Hynix shares lost up to 20% this week despite strong earnings. At the same time, software stocks staged a recovery, inflicting losses on Aschenbrenner's short positions.
Margin calls and the overnight auction
As the value of the fund's collateral shrank, banks demanded additional margin. Aschenbrenner needed cash immediately. An auction was held on Wednesday, stretching late into the night. Several competitors were approached. Citadel, led by Ken Griffin, emerged as the winning bidder, acquiring the portfolio at a discount exceeding 10% to its current value. According to the New York Times, Situational Awareness sold more than $10 billion in holdings in total. The fund retained its stake in AI firm Anthropic, worth an estimated $3.5 billion to $5 billion, and its remaining investments are valued at more than $10 billion. Aschenbrenner told investors that the fund was still up 80% year-to-date.
The decline followed 'phenomenal price increases' in recent months.
Market impact and recovery
Griffin's intervention is seen by some as preventing a broader downward spiral in AI and chip stocks. Markets rebounded sharply on Thursday after the sale was completed. The Handelsblatt noted that Citadel's purchase effectively halted the sell-off, helping to stabilise the sector. Meanwhile, speculation has circulated on social media that Griffin may have deliberately unsettled markets ahead of the US Federal Reserve's interest rate decision on Wednesday. Raiffeisen Schweiz chief investment officer Matthias Geissbühler called Aschenbrenner's fall a textbook case of greed overwhelming risk management, adding that the young manager was naive and lacked experience.
A wedding and a warning
Aschenbrenner is scheduled to marry his fiancee Avital Balwit, chief of staff to Anthropic CEO Dario Amodei, this weekend. The collapse comes at an awkward moment, with the wedding preparations reportedly distracting him during the critical week. The event has also sparked a broader debate about the durability of AI-driven market exuberance. Aschenbrenner's fund had achieved a total return of 1,551% since launch, but as commentators noted, two years in a favourable market can obscure the difference between skill and concentrated risk.
