Jane Street lost $15 billion in its first down month in a decade

Jane Street posted roughly $15 billion of losses in July — its first monthly slump in about a decade — as AI-focused hedge fund Situational Awareness swooned and dragged down asset prices across equity markets, according to a person familiar with the matter.

Jane Street, which invests in Situational Awareness and directly invests in AI ventures, suffered a rare and severe downturn amid volatile stock markets. The company’s investment in the hedge fund, as well as wrong-way bets in Asian equity markets, drove part of the losses, said the person, who asked not to be identified citing private details.

“July was a bad month,” Turner Batty, a Jane Street partner, said in an internal note.

Still, the firm has generated more than $40 billion of net trading revenue so far this year, more than it did in all of 2025 when it set a Wall Street record, the person said.

“Despite the large year-to-date increase in trading capital, the recency of these losses has caused........

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