Leopold Aschenbrenner’s hedge fund Situational Awareness has started building relationships with new brokerages as it attempts a rebound from the largest loss in hedge fund history. Aschenbrenner, in his mid-twenties, was a star AI investor before tens of billions in losses forced him to sell a large chunk of his portfolio and cut leverage.

The investor has recently begun working with specialist brokerage Clear Street, people familiar said, as he rebuilds a portfolio of aggressive tech bets. Hedge funds rely on brokers to execute bespoke derivatives and provide financing. Situational Awareness averted near collapse this summer by offloading most public-market positions to Ken Griffin’s Citadel, but Aschenbrenner vowed a comeback.

After the sale, he said he would “fight another day” and “learn the necessary lessons” from the sell-off that led to a 67 per cent plunge in July. The fund was still up 80 per cent this year, he told investors. Now, Aschenbrenner is rebuilding large trading positions in tech stocks such as AMD, Intel, SK Hynix and Sandisk and AI start-ups including Core Weave, sources said. His efforts have been bolstered by new Wall Street relationships like Clear Street.

While well known as a tech-focused brokerage, Clear Street is far smaller than rivals like Goldman Sachs, JPMorgan and Citigroup. Aschenbrenner told investors in July that Situational Awareness was “continuing to operate as a hybrid public-private fund as before” but would “manage our public book on a fully-paid-for basis.” Using fully-paid options reduces risk. In recent days, the fund placed large new bets using “flex options,” which allow customised terms and can only be made through large brokerages. The trades show small premiums for magnified exposure. Some prime brokers said Aschenbrenner will use far less leverage than previously. Situational Awareness and Clear Street declined to comment.