Hedge funds have loaded up on stock shorts this month, pushing bearish bets near a five-year high and raising the risk of a sharp squeeze if markets rebound.

Across global equities, Goldman Sachs Group Inc.’s prime brokerage desk says short sales have exceeded long purchases by a ratio of roughly five to one. Short leverage across its book sits in the 99th percentile over the past five years. Net leverage among fundamental long/short funds, a gauge of how much long exposure exceeds shorts, is near a three-year low, despite a rise in gross leverage.