Jane Street Suffers $15 Billion Loss as AI Selloff Triggers Hedge Fund Collapse

Jane Street Records First Negative Month Since 2016

Jane Street suffered a staggering $15 billion loss in July, marking its first negative trading month since 2016, according to sources familiar with the matter and an internal note seen by Reuters1

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. The Wall Street trading firm's losses stemmed primarily from its exposure to AI-focused hedge fund Situational Awareness and the broader AI selloff that hammered tech sector stocks throughout the month. Despite this setback, Jane Street has generated trading revenue exceeding $40 billion year-to-date, easily surpassing the $39.6 billion it recorded for all of 20251

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. This performance continues to outstrip trading revenue at the largest banks and other market-making rivals.

Situational Awareness Collapse Triggers Margin Calls

The crisis centered on Situational Awareness, an AI-focused hedge fund run by Leopold Aschenbrenner, a former OpenAI researcher nicknamed the "Nostradamus of AI"2

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. The fund, which counted Jane Street among its investors, experienced a catastrophic drawdown after performing strongly in the first half of 2026. In a note to employees on Friday, Jane Street executives acknowledged that Situational Awareness "became large by performing well in the first half of the year" before suffering "a large drawdown that left our stake about flat on the year"1

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. The fund's assets plummeted from a $45 billion peak to roughly $10 billion within a single month3

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. Buckling under extreme leverage and relentless margin calls, Situational Awareness was forced into a fire sale, offloading the bulk of its stock portfolio to billionaire Ken Griffin's Citadel4

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AI-Exposed Stocks Plunge Up to 50%

The July market volatility proved particularly brutal for AI-exposed stocks and semiconductor stocks. Jane Street noted in its internal communication that "AI-exposed stocks were down a lot during July, several of the largest memory and semiconductor stocks were down around 50%"2

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. The firm's losses weren't limited to its Situational Awareness investment. Jane Street also took hits from long positions in non-AI Asian stocks, many of which had outperformed markets earlier in the year1

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. The proprietary trading heavyweight acknowledged that "we largely lost on the same portfolio of trades that had strong outperformance in the second quarter"4

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. The firm's short-term hedges provided little protection because the losses in AI infrastructure stocks were relatively spread throughout the month rather than concentrated in a single sharp drawdown.

Risk Aversion and Capital Restructuring Follow

The July losses forced Jane Street into immediate risk management adjustments. The firm's revenue dropped roughly 25% from its peak at the end of June1

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. In response, executives told employees the firm would be "more selective about risk," having "closed a significant portion of our risk in the specific areas we lost on in July, and have also reduced risk taking in other strategies"2

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. The rare stumble was disclosed to lenders as Jane Street executes a significant capital restructuring, shifting approximately $11 billion of its public debt into private hands, enlisting institutional heavyweights such as Pimco to absorb the obligations3

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. Despite the setback, the firm maintained that "market volumes have been strong, and we've continued to make improvements to our short time horizon strategies"1

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. The episode underscores the severe liquidity pressures and leverage risks that defined the July reckoning across multiple AI-centric hedge funds, revealing how even market-making juggernauts with 25 years of data-driven real-time pricing tools remain vulnerable to concentrated sector drawdowns.