Leopold Aschenbrenner spent the first half of 2026 as one of the most celebrated investors in finance. By the end of June, according to Financial Express, his Situational Awareness fund had returned 439% year-to-date and 1,551% since inception, built on a concentrated bet that artificial intelligence would reshape the economy. The Wall Street Journal reported he was hailed as the "Nostradamus of AI."
Then July happened. The Wall Street Journal reported the fund fell 67% in a single month during an AI stock rout. The Journal's account, summarized by Techmeme, says the fund "took on too m" — its reporting centers on Aschenbrenner having taken on too much of something, and on him assuring investors over two days that he would change how he managed the portfolio.
The mechanism, per 24/7 Wall St., was margin — borrowed money that amplifies gains on the way up and losses on the way down. The outlet noted the blowup came days after CNBC's Jim Cramer had warned about exactly that danger. According to MSN's report, Aschenbrenner was forced to unwind all of the fund's public stock positions; CNN reported that Citadel stepped in, and Business Insider said AI stocks actually jumped once Citadel bought the portfolio — the forced selling had been dragging the whole sector down.
CNN described the episode as a cautionary tale for the AI era, one that sent shockwaves through global markets and exposed the riskiest players. Business Insider noted the rebound likely came too late to rescue other hedge funds' July returns. MarketWatch, meanwhile, suggested AI stocks may have bottomed out.
It matters because a single leveraged fund moved an entire sector, showing how much of the AI trade rests on borrowed money rather than conviction alone.