AI investor’s $45B hedge fund implodes after risky chip stock bets

The “Nostradamus of AI” made a pair of $5 billion bets — only to watch his $45 billion hedge fund implode days before his lavish California wedding.

Leopold Aschenbrenner’s Situational Awareness fund held a $5.7 billion stake in SanDisk and $5.6 billion in Micron Technology at the end of June, according to quarterly filings.

The two bets made up more than half of his US stock portfolio, which had ballooned from less than $4 billion to more than $20 billion during the second quarter.

Then the wheels came off.

SanDisk shares plunged 47% in July, while Micron tumbled 29%, helping wipe out roughly 67% of the fund’s portfolio value in a single month. The losses triggered margin calls and forced Situational Awareness to sell billions of dollars of holdings in a fire sale to billionaire Ken Griffin’s Citadel.

Bloom Energy, the fund’s next-largest holding, accounted for nearly 10% of the portfolio and also plunged 31% during the month.

Aschenbrenner had also sharply increased his positions in TSMC and opened a $1.2 billion position in Nebius before those stocks fell alongside the broader AI trade.

The carnage shrank Situational Awareness from roughly $45 billion to about $10 billion — though the fund remained up sharply for the year after reportedly returning 439% during the first half of 2026.

The disastrous bets also reportedly cost Wall Street trading giant Jane Street nearly $15 billion.

Aschenbrenner, 24, has become one of Silicon Valley’s most closely watched AI thinkers. He graduated from Columbia University at 19 and later worked at Sam Bankman-Fried’s now-defunct FTX before joining OpenAI in 2023.

He was fired the following year after allegedly leaking sensitive information to an Anthropic executive’s husband.

Aschenbrenner quickly rebuilt his reputation with his 165-page essay, “Situational Awareness: The Decade Ahead,” which predicted artificial general intelligence could arrive by 2027 and warned of the geopolitical threat posed by superintelligent AI.

His hedge fund launched in 2024.

The spectacular collapse came just days before Aschenbrenner’s lavish California wedding.

Earlier this month, the AI investing wunderkind made headlines once more for placing big bets again, less than a week after his much-watched hedge fund Situational Awareness saw a spectacular blow-up.

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