24-Year-Old AI Hedge Fund Phenom Leopold Aschenbrenner Hits $20B AUM and 1,000%+ Returns

Leopold Aschenbrenner, a 24-year-old former OpenAI researcher with no prior professional investing experience, has built one of the most talked-about hedge funds on Wall Street in under two years. His firm, Situational Awareness, has grown from a few hundred million dollars at launch to more than $20 billion in assets under management — approaching the scale of Bill Ackman's Pershing Square and Dan Loeb's Third Point. The fund is up roughly 270% after fees through May 2026 alone, and more than 1,000% after fees since inception.

The fund's single biggest winner is a stake in Anthropic, first acquired in a February 2025 funding round that valued the AI company at $61.5 billion. That position has since ballooned as Anthropic's valuation soared to $965 billion, and now accounts for approximately one-fifth of the fund's entire assets. Other early wins include an investment in South Korean memory-chip maker SK Hynix, initiated in November 2024, which subsequently joined the trillion-dollar market-cap club. The fund did stumble in early 2025 when DeepSeek's low-cost AI model triggered a selloff in Nvidia and AI-adjacent names, but it recovered sharply and ended 2025 up about 200%.

Quant-trading powerhouse Jane Street — known for rarely allocating capital to outside managers — is now an investor in the fund, a signal that carries unusual weight in hedge-fund circles. Jane Street has also co-invested alongside Situational Awareness in venture deals, including leading a February funding round for MatX, an upstart AI chip designer, and participating in a new round for Fluidstack, an AI cloud-computing provider.

Aschenbrenner's cult following traces back to a sprawling 165-page essay published in 2024 titled "Situational Awareness: The Decade Ahead," which mapped AI's trajectory by modeling compounding improvements in compute, algorithms, and model refinement. The paper was shared by Michael Dell, Ivanka Trump, and others, and made him an intellectual touchstone in both tech and finance circles. He co-founded the firm with Carl Shulman, an AI philosopher who previously worked at Peter Thiel's macro hedge fund; early backers included Stripe co-founders Patrick and John Collison and Meta AI leaders Daniel Gross and Nat Friedman.

Despite shunning public appearances and rarely posting on social media, Aschenbrenner has become the closest thing the AI investment boom has to a celebrity stock picker. His mandatory quarterly regulatory filings are treated as major events — trading app Autopilot launched a feature letting retail users copy his disclosed trades, and a single filing revealing a position in solar manufacturer T1 Energy sent the stock up 23% on its second-highest trading volume ever. Podcaster Tim Ferriss dubbed him the "Nostradamus of AI," and a misread of options data in May briefly sent the internet into a panic under headlines claiming he had "shorted the entire market."