“He’s Back, He’s Bigger Than Ever”: 24-Year-Old Who Blew Up $45 Billion Hedge Fund Returns With AI Options Bets

On September 11, 2026, Jim Cramer posted five words on X in reaction to CNBC reporting that instantly ricocheted across finance Twitter: “HE’s back, he’s bigger than ever.” He was amplifying news that Leopold Aschenbrenner’s fund, Situational Awareness, had turned active in the options market again, roughly six weeks after one of the most dramatic hedge fund blowups in recent memory. The post was a headline reaction, not a market call.

The name carries weight because of what happened in July.

Who Aschenbrenner Is, and What Happened in July

Leopold Aschenbrenner is a former OpenAI researcher who built Situational Awareness into an AI-focused hedge fund. The fund started with roughly $250 million in 2024 and, using leverage as high as 400%, grew to approximately $45 billion at the start of July 2026 before the wheels came off. From launch through the end of June, the fund had posted returns exceeding 1,000%.

The collapse was swift. A sharp drop in AI infrastructure stocks triggered margin calls from prime brokers. The fund’s two largest disclosed positions, SanDisk and Micron Technology, which together accounted for more than 56% of its U.S. equity holdings at the end of June, fell nearly 47% and roughly 29%, respectively, in July. Bloom Energy slid 32% that same month. Unable to meet collateral demands, Aschenbrenner was forced to unwind all public stock positions, selling the bulk of the portfolio to Ken Griffin’s Citadel in what amounted to a fire sale. The Wall Street Journal and CNBC both reported the Citadel transaction on July 30, 2026. When the dust settled, the fund’s assets had fallen to roughly $10 billion, a loss of approximately $35 billion. The Financial Times described it as the largest dollar loss in hedge fund history.

Even as the crisis played out, the fund held onto private stakes in companies including Anthropic, Fluidstack, and MatX. Then, in early August, Situational Awareness made a $400 million investment in an undisclosed private company, adding to a $100 million stake it had already taken in the same firm, bringing the combined commitment to $500 million. One source identified the recipient as semiconductor manufacturing startup Source Foundry, though the fund declined to comment.

Back in the Market, This Time Through Options

CNBC’s David Faber broke the return story on September 11, 2026, reporting that Situational Awareness had been buying options positions in a cluster of AI-adjacent names: Advanced Micro Devices (NASDAQ:AMD | AMD Price Prediction), Bloom Energy (NYSE:BE), and CoreWeave (NASDAQ:CRWV). The fund also took positions in SK Hynix and SanDisk, and bought options in the Roundhill Memory ETF (NYSEARCA:DRAM). The purchases were made between September 2 and September 10, according to sources cited by CNBC. Whether Situational Awareness was drawing on assets that survived the summer or had attracted new investor capital remained unclear.

The fund’s choice of instrument was telling. Options let an investor control a large position for a fraction of the cost of buying shares outright, which magnifies both gains and losses. That dynamic is exactly why a fund rebuilding from a wipeout might reach for them, but it is also why the risk profile is significant. Notably, Protos reported on September 14 that by Monday’s open, every one of the six tickers tied to the new positions had already fallen, down as much as 8% from the prior Friday’s close. (For readers who want a framework for speculating without overexposing their portfolio, we put together sizing and exit rules here: Small Stakes, Big Swings.)

The AI Infrastructure Stocks at the Center of the Trade

The specific names Situational Awareness targeted reflect its core thesis: that the physical backbone of AI, memory, compute, and power, will generate outsized returns as models scale. AMD, CoreWeave, SanDisk, SK Hynix, and Bloom Energy all sit squarely within that infrastructure layer. It is a similar thesis to the one that drove the fund’s original public portfolio, which means the concentrated bet on those same names the second time around drew immediate skepticism from observers noting the continuity.

Hovering over the entire AI trade, as always, is NVIDIA (NASDAQ:NVDA), whose market cap sits near $5.34 trillion as of mid-October 2026. NVIDIA’s Q2 FY2027 report, filed with the SEC on August 26, 2026, delivered revenue of $96.22 billion, up 105.8% year-over-year, with Data Center revenue of $89.02 billion, up 117% year-over-year. Guidance for Q3 called for revenue of $108.0 billion, plus or minus 2%. The earnings release also flagged supply commitments that had surged to $279 billion, tied largely to Vera Rubin production.

Jensen Huang framed the backdrop on the earnings call: “AI has reached its inflection point. It’s doing useful work. Its tokens are productive and profitable. Now, compute is revenue.”

Editor’s note: This update adds the specific tickers CNBC identified in Situational Awareness’s September 2026 options positions (AMD, Bloom Energy, CoreWeave, SK Hynix, SanDisk, and the Roundhill Memory ETF), corrects the original claim that no outlets had named the tickers, refreshes NVIDIA’s market cap to approximately $5.34 trillion as of mid-October 2026, and adds post-publication context including Situational Awareness’s $400 million private investment in early August, the fund’s reported 1,000%-plus returns from launch through June, the Protos report that the new options positions were already underwater by September 14, and details on how Citadel unwound more than 80% of the portfolio it acquired from the fund.

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