"According to Goldman Sachs Prime Services, this week represented the largest active hedge fund de-grossing since February 2009. Funds in their coverage sold long positions and covered shorts in every sector," the investment bank wrote in a note late Friday.

"Despite this active deleveraging, hedge fund net and gross exposures on a mark-to-market basis both remain close to the highest levels on record, indicating ongoing risk of positioning-driven sell-offs."

(Reporting by Joshua Franklin in Miami and Alden Bentley in New York; Editing by Lisa Shumaker)