Leopold Aschenbrenner's Situational Awareness fund forced into fire sale after margin calls

Leopold Aschenbrenner, the former OpenAI researcher who wrote the widely circulated 2024 essay “Situational Awareness,” ran the hedge fund of the same name on heavily leveraged bets on AI infrastructure stocks. Reporting said the fund had returned roughly 439% in the first half of 2026, taking assets under management as high as $45 billion, before AI-infrastructure names it held — including SK Hynix and CoreWeave — fell sharply through July on concern that capital spending was outrunning near-term revenue.

The losses, amplified by leverage reported at around four times, triggered margin calls from prime brokers including Goldman Sachs, JPMorgan Chase and Bank of America. Reporting said the fund lost around two-thirds of its value during July, and on 30 July it sold its entire public equity book — long and short positions together — to Ken Griffin’s Citadel in a single trade before markets opened, leaving assets under management at around $10 billion, down from the $45 billion peak.

What the fund kept was its private holdings, chief among them a stake in Anthropic reported at around $5 billion. TechCrunch reported that the appreciation of that stake, acquired when Anthropic was valued far below its subsequent funding rounds, was reported to have kept the fund in positive territory for the year overall despite the scale of the public-market losses. The episode became a reference point in commentary on AI-infrastructure valuations: a fund built on conviction that frontier AI was underpriced was unwound by a sharp, if short-lived, repricing of the infrastructure stocks it held to express that view.