Nov. 23 (Bloomberg) -- Some European quantitative funds may have lost 15 percent this month following declines in equity markets, according to strategists at JPMorgan Chase & Co. ``We expect some long-only quant managers, regardless of their strategies, to be down at least 10-15 percent for the month,'' Marco Dion and Matthew Burgess, analysts in JPMorgan in London, wrote in a report today. ``Quant bloodbath ? again.'' Quantitative managers, who use mathematical strategies to make investments, were blamed by some investors for a sell-off that wiped out almost $400 billion in value from the Dow Jones Industrial Average in the U.S. from July 19 through Aug. 16. Funds were forced to sell because many owned the same holdings and ran similar computer models that were equally jarred by widening credit spreads and increasing stock-price volatility. Europe's Dow Jones Stoxx 600 Index has dropped 8.1 percent so far in November, headed for the biggest monthly decline since 2002.