Federal Reserve and Bank of England ramp up scrutiny of bank-trading firm ties after Jane Street’s $15B loss

Jane Street, the quantitative trading powerhouse that has quietly become one of the most profitable firms on Wall Street, just had its worst month in a decade. The firm posted a roughly $15 billion trading loss in July 2026, its first month of negative trading revenue since 2016. Now the Federal Reserve and the Bank of England are using the episode as a catalyst to take a harder look at the risks banks face from their deep financial ties to firms like Jane Street.

The loss, while jaw-dropping in isolation, didn’t exactly put Jane Street on life support. By mid-August 2026, the firm had still accumulated over $40 billion in net trading revenue year-to-date, already surpassing its full-year 2025 haul of approximately $39.6 billion.

What went wrong in July

The culprit was concentration risk in a sector Jane Street had been riding hard: artificial intelligence. A significant chunk of the losses stemmed from investments linked to Situational Awareness, an AI-focused hedge fund, along with sizable positions in AI-related equities that got hammered during a broader tech selloff.

Memory and semiconductor stocks were hit especially hard, with some corners of the sector declining nearly 50%.

Why regulators are paying attention now

The Bank of England had actually been sounding alarms before Jane Street’s July stumble. Back in April 2026, BoE officials warned against proposals to ease capital requirements for trading firms, arguing that loosening the reins could threaten financial stability.

The BoE’s July 2026 Financial Stability Report doubled down on those concerns, highlighting significant vulnerabilities arising from banks’ interlinkages to non-bank financial institutions, a category that encompasses trading firms, hedge funds, and other entities that operate outside the traditional banking perimeter but are deeply connected to it through lending, clearing, and counterparty relationships.

S&P Global Ratings put an even finer point on it, warning that banks carry trillions in aggregate exposures to hedge funds and trading firms. The rating agency described this situation as carrying “inherent fragility” driven by leverage and concentration risks.

The Federal Reserve, for its part, is now conducting its own parallel review of how US banks manage counterparty risk from major trading firms.