Jane Street lost $15 billion in a single month, and AI funds plummeted, causing top trading giants to suffer rare losses

Comparative news, according to the Financial Times, Wall Street quantitative trading giant Jane Street experienced significant losses due to investing in the AI hedge fund Situational Awareness, which lost about $15 billion in a single month in July.

People familiar with the matter revealed that Jane Street released the loss data when disclosing the financial situation to creditors. This disclosure is related to a private debt financing transaction of about $146 billion. The deal, led by J.P. Morgan Chase, involved transferring approximately $11 billion of public debt to private investors, including Pacific Investment Management (Pimco).

The loss stemmed from a sharp correction in US AI stocks in July. Situational Awareness is an AI-themed hedge fund founded by former OpenAI employee Leopold Aschenbrenner and has received investment from Jane Street. The fund was hit hard during the market reversal and forced to sell part of its public stock positions to Citadel due to its previously concentrated and highly leveraged bets on AI stocks.

Despite huge losses in a single month, Jane Street has maintained strong profitability in recent years. According to the data, the company's net transaction revenue for the first quarter of 2026 reached a record of US$161 billion, and net transaction revenue for the full year of 2025 was approximately US$40 billion.

Market sources pointed out that this loss is rare for a proprietary trading agency that has been low-key for a long time and has occupied an important position in the global market. Jane Street's subsequent shift to private debt market financing will also reduce the scope of its disclosure of financial information to the public market.