Quant hedge funds are having a rough start to 2026. The first two weeks of January produced the worst 10-day stretch for systematic long-short equity managers since October 2025, driven not by a broader market meltdown but by crowded trades blowing up: their own crowded trades blowing up in their faces.
UBS estimated that US-focused quant funds dropped approximately 2.8% in the first two weeks of January 2026. Goldman Sachs prime brokerage data put the average loss for systematic managers at around 1% over the worst 10-day window, but individual firm numbers tell a sharper story.
## Who got hit, and how hard
Renaissance Technologies reported a loss of approximately 4% in the early days of January. Schonfeld’s quant strategies fell roughly 3.9%. Cubist was down around 2%. Qube, Man Group’s AHL division, Two Sigma, and Engineers Gate all felt the same headwinds.
The culprit was not a market-wide crash. The S&P 500 remained relatively buoyant during this period. What actually drove the losses was a combination of crowded positioning and a short squeeze in lower-quality stocks. Lower-quality, highly shorted equities surged, forcing funds that were short those positions to cover. That covering pressure drove prices even higher, which forced more covering.
