New regulatory filings show that Situational Awareness’s SanDisk and Micron bets consumed more than half of the fund’s disclosed US equity portfolio at the end of June, weeks before a brutal sell-off in AI-linked stocks triggered margin calls and forced a fire sale to Citadel.
A portfolio built on memory-chip concentration
Situational Awareness, the hedge fund founded by Leopold Aschenbrenner, held a $5.7 billion stake in SanDisk and a $5.6 billion stake in Micron at 30 June, according to the fund’s quarterly 13F portfolio filing released on Friday. Together those two positions accounted for 56% of a US stock portfolio worth just over $20 billion, excluding put and call options.
A 13F (a quarterly disclosure filed with US regulators) captures only a single snapshot of one day in a three-month period. It also excludes short positions, foreign-listed shares, non-equity assets, and private investments such as Situational’s reported stake in Anthropic. The filing therefore does not represent the full shape of the fund’s strategy.
The scale of the portfolio’s growth in the quarter is nonetheless striking on its own terms. At the end of March, Situational directly owned less than $4 billion of stocks, led by an $879 million stake in Bloom Energy. By end of June, the value of its direct holdings had soared more than fivefold in three months.
Aschenbrenner and his team more than doubled their direct stake in SanDisk to around 2.5 million shares, and lifted their Micron position from roughly 17,000 shares to 4.8 million. They also ramped up Situational’s Taiwan Semiconductor Manufacturing Company (TSMC) stake from around 22,000 American Depositary Shares to 2.6 million, and established a $1.2 billion stake in Nebius at the quarter’s close.
Insurance stripped away as Situational Awareness SanDisk Micron exposure grew
As the fund concentrated on SanDisk and Micron, it simultaneously shed much of the hedging that might have cushioned the eventual fall. Situational cut its option positions from 16 to three, reducing its put positions (instruments that pay out when a stock declines) from 11 to one. Its previous put book had included coverage on the VanEck Semiconductor ETF, Nvidia, Oracle, Broadcom, AMD, Micron, TSMC, ASML, and Intel. Bullish call positions fell from five to two.
In July, SanDisk and Micron shares fell by 47% and 29%, respectively, as investors took profits after a long run and worried about valuations. Both stocks have since clawed back some ground, with investors wagering they will benefit from continued AI infrastructure spending.
Leverage, prime brokers, and Citadel’s rescue purchase
The filing tells only part of the story. According to Yahoo Finance, the fund had used as much as 400% leverage, amplifying both gains and losses far beyond what the underlying equity positions suggest. When AI stocks fell in July, that leverage meant Situational’s highly concentrated portfolio sank by 67%, triggering margin calls from lenders.
Yahoo Finance also reports that Bank of America, Goldman Sachs, and JPMorgan Chase had been working with the fund to meet margin requirements in the period before the eventual sale. The fund, which peaked at $45 billion at the start of July, saw its holdings drop to roughly $10 billion after Citadel acquired its leveraged stock positions. Aschenbrenner, a Columbia valedictorian and former OpenAI researcher, had built Situational to that peak value in under two years and reported a 1,000% gain since inception earlier this year.
A personal detail adds a further layer to the Anthropic connection already present in Situational’s private holdings. CNBC reports that Aschenbrenner is engaged to Avital Balwit, chief of staff for Anthropic chief executive Dario Amodei.
Both SanDisk and Micron have recovered partially since July’s lows, and Citadel’s acquisition of the leveraged positions means the immediate margin-call pressure has passed. Aschenbrenner did not respond to a request for comment from Business Insider.