Hedge Funds Improve Market Functioning, but Can Also Amplify Stress

IMF Blog, October 6, 2026

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Since 2013, gross assets under management have tripled, to $13 trillion.
Gross notional exposures, which include on- and off-balance-sheet positions, are about $40 trillion.
Hedge funds held about 9 percent of US Treasurys in 2025.
Hedge funds invest and borrow with relatively few constraints, allowing investment in illiquid assets, extensive use of leverage, and rapid position adjustment.
In normal times, these features support liquidity, price discovery, and risk sharing; in stressed conditions, they can transmit and amplify shocks.

Key balance-sheet vulnerabilities: leverage, crowded positions, and redemption pressures.
Leverage sources cited: repurchase agreements, prime broker credit, and derivatives.
Mechanism: rising volatility or tighter financing can trigger margin calls, forcing hedge funds to reduce exposures or unwind positions, shifting them from liquidity providers to amplifiers of market stress.
Crowded trades and fast investor withdrawals can produce synchronized unwinds and self-reinforcing feedback loops among losses, deleveraging, and withdrawals.

The analysis uses spikes in the CBOE Volatility Index (VIX) to measure periods of stress.
Stocks most widely held by hedge funds are 10 percentage points more volatile than the least crowded stocks.
Those crowded stocks suffer 4 percentage points deeper peak-to-trough losses than the least crowded stocks.
Volatility and losses are larger when hedge funds holding these stocks experience simultaneous investor redemptions.
Leverage amplifies these effects, underscoring the interaction of borrowing, crowded positions, and correlated investor withdrawals in magnifying shock transmission.

Prime brokers (typically large dealer banks) provide financing and trading services; losses at hedge funds can weigh on these banks and reduce their capacity to lend during stress.
Hedge fund stress can spill across borders: when the VIX rises and global risk sentiment deteriorates, stock markets with larger hedge fund presence tend to suffer larger declines.
Cross-border and less liquid markets are particularly vulnerable because fewer buyers may be available to absorb sales when hedge funds reduce positions.

Surveillance gaps: many authorities lack information on leverage, derivatives exposures, prime broker relationships, and cross-border activities; improved reporting and information sharing is central to effective surveillance.
Policy measures should be calibrated to the source of risk:
- For synchronized deleveraging across many funds: market-wide measures such as minimum margins and haircuts, and stronger collateral management.
- For concentrated risks in specific firms or exposures: entity- and concentration-based measures, including risk-based leverage limits, margin or capital add-ons, and large-exposure limits.
Supervisory priorities:
- Ensure prime brokers maintain strong counterparty risk management and monitor exposures to highly leveraged hedge funds.
- Conduct system-wide stress tests to assess how hedge funds and counterparties respond to shocks and how pressures could propagate.
- Early identification of vulnerabilities to prevent them from becoming systemic risks.