Jane Street suffers $15bn loss in July market chaos

Quantitative trading giant Jane Street recorded a $15 billion loss in July after a market meltdown tied to Situational Awareness — one of the largest single-month hits ever absorbed by a Wall Street firm. The firm has still posted substantial trading revenues overall in 2026, cushioning the blow. The loss underscores how concentrated and fragile large quant positions can become when volatility spikes.