Goldman Sachs Prime Brokerage data shows that hedge funds experienced another "rare multi-strategy synchronized decline since the pandemic" this Thursday (October 15), the third such event since 2026. Quantitative funds, in particular, suffered a severe blow of -3.7 standard deviations that day, marking their worst single-day decline since August 19. Monthly losses for Asia-Pacific hedge funds widened to -6.8%, with AI-related positions in South Korea and Taiwan becoming major casualties. Marco Laicini of Goldman Sachs Prime noted that three "once-in-five-year" events occurring within ten months indicate a systematic underestimation of extreme risk in the hedge fund industry's current VaR models. At the market level, Goldman Sachs Prime's overall book leverage remains high at 310%, with Taiwan positions near a five-year high. Coupled with the approaching options expiration day on Friday, structural risks have not yet dissipated.