The Rise and Implosion of Leopold Aschenbrenner's $45 Billion AI Hedge Fund

Leopold Aschenbrenner, a 24-year-old Columbia valedictorian who once told friends he planned to buy galaxies, built one of the most extraordinary — and brief — careers in AI finance. After stints at Sam Bankman-Fried's FTX Future Fund in the Bahamas and OpenAI in San Francisco, he parlayed a 165-page viral manifesto called 'Situational Awareness' into a hedge fund that eventually managed $45 billion in assets, backed by investors who believed either in his prophecy about superintelligence or his ability to profit from it.

Aschenbrenner's ascent was fueled by an unusually dense network of relationships across Silicon Valley's AI elite. He won over Jane Street — a quant trading firm that rarely backs outside managers — along with Stripe co-founders Patrick and John Collison. His fund concentrated heavily on the AI supply chain: semiconductors, energy, software, and private stakes in companies like CoreWeave and Cerebras. The crown jewel was a position in Anthropic, whose CEO Dario Amodei, top scientist Jared Kaplan, and other key executives were regulars at Aschenbrenner's San Francisco mansion. He married Avital Balwit — Dario Amodei's chief of staff — just days before his fund collapsed, with Amodei himself attending the wedding.

His OpenAI tenure was turbulent. He clashed with management over what he described as lax security protocols around potential Chinese espionage, circulated a critical memo directly to the board, and was fired after sharing what executives considered sensitive company information with Holden Karnofsky, a prominent effective altruism figure married to Anthropic president Daniela Amodei. Aschenbrenner rejected a nearly $1 million equity severance rather than sign an NDA, and OpenAI disputes key elements of his account of the departure.

The fund unraveled in July when cheap, powerful AI systems from China rattled markets and triggered a brutal tech selloff. Situational Awareness was running approximately 3-to-1 leverage — more than comparable funds — on a heavily concentrated, AI-long portfolio. The exposure proved fatal. Two days before Aschenbrenner's wedding, the fund blew up. Securities regulators have since opened an investigation into its trading activity, though no formal allegations have been made. On Wall Street, veterans called it a classic story of hubris and overleveraging. In Silicon Valley, his stature among true believers has reportedly only grown.