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

Jane Street took a rare hit in July, losing roughly $15 billion in what was its first monthly slump in about a decade. The blow came as an AI-focused hedge fund, Situational Awareness, stumbled and as volatile stock markets pushed asset prices around.

The firm’s exposure to that fund, plus wrong-way bets in Asian equities, helped drive the losses, according to a person familiar with the matter. Jane Street invests in Situational Awareness and also puts money directly into AI companies. That has made it one of the more visible winners of the AI trade. July reminded everyone that the same trade can turn nasty fast.

Turner Batty, a Jane Street partner, told staff in an internal note that “July was a bad month.” He also said the firm had become more selective about risk after the losses, had closed a significant portion of its risk in the areas that hurt it in July, and had reduced risk-taking in other strategies. The message was plain: pull back a little, at least where the pain was most obvious.

And yet the broader picture is still huge. The person said Jane Street has generated more than $40 billion of net trading revenue so far this year, more than it made in all of 2025, when it set a Wall Street record. The company has also been working on a $14.6 billion bond issue to overhaul its debt load, with investors including Pacific Investment Management Co., Capital Group and Fidelity buying in across three bonds. That refinancing is meant to fund technology infrastructure, expand trading strategies, and help replace floating-rate loans inside an $11 billion capital stack.

Situational Awareness’ own rough patch spilled into the story too. In July it faced margin calls after AI bets soured, then struck a deal with Citadel to sell off a large part of its public equity book. Jane Street said the fund’s drawdown left its stake flat on the year, though still up over the life of the bet. For a firm that has spent recent years collecting records, July was a reminder that even a powerhouse can get rattled when the market starts moving the other way.