In a new blog post, the International Monetary Fund said hedge funds improve liquidity, price discovery and risk sharing in normal markets but can amplify stress through leverage, crowded positions and correlated investor withdrawals. Based on analysis in the Global Financial Stability Report, it called for better reporting and information sharing on leverage, derivatives exposures, prime broker relationships and cross-border activities, alongside policy measures calibrated to the source and concentration of risk. Hedge funds’ gross assets under management have tripled since 2013 to USD 13 trillion, while gross notional exposures total about USD 40 trillion. During periods of market stress, stocks most widely held by hedge funds were 10 percentage points more volatile and experienced losses from peak to trough that were 4 percentage points deeper than the least crowded stocks. Similar vulnerabilities can affect sovereign funding markets, including through leveraged US Treasury basis trades, and spread to dealer banks and less liquid markets across borders. The IMF recommended minimum margins and haircuts, stronger collateral management and systemwide stress tests where synchronized deleveraging poses broad market risks. Where exposures are concentrated, authorities could consider leverage limits based on risk, margin or capital add-ons and large exposure limits, while supervisors should strengthen oversight of prime brokers’ counterparty risk management and exposures to highly leveraged funds.