Margin Call
A margin call is a demand by a broker, clearinghouse, or counterparty for an investor to deposit additional collateral (variation margin or supplemental initial margin) into a margin account when the equity in that account has fallen below the required maintenance margin threshold due to adverse price movements in open positions.
Key takeaways
- Margin calls must typically be met by the next business day (or within a specified time window in the case of intraday calls for highly leveraged accounts); failure to meet a margin call gives the broker the right to forcibly liquidate positions.
- Margin calls can have systemic implications when many participants receive simultaneous calls during market stress, forcing correlated liquidations that amplify price declines—a mechanism that contributed to market crises in 1987, 1998, 2008, and 2020.
- For futures accounts, variation margin calls are settled daily through the clearinghouse; for securities margin accounts, calls may occur less frequently but can be triggered intraday during extreme volatility.
- Portfolio managers facing margin calls must decide whether to meet the call by depositing cash, liquidate positions to reduce required margin, or use existing liquid assets (T-bills, money market funds) as eligible collateral.
- Anticipating and stress-testing potential margin calls under adverse market scenarios is a critical component of hedge fund liquidity risk management, ensuring that the fund holds sufficient unencumbered liquidity to meet calls without forced liquidation.
Explanation
Margin calls represent the intersection of credit risk management and market dynamics, serving as a mechanism that enforces discipline on leveraged market participants while simultaneously creating the potential for feedback loops that amplify market volatility. The margin call process is simple in theory: when a leveraged position moves against the investor and account equity falls below the maintenance floor, the clearinghouse or broker demands restoration of the initial margin buffer. In practice, margin calls during periods of market stress can become a powerful procyclical force.
The mechanics of a margin call differ across market structures. In exchange-cleared futures, variation margin settlement is automatic and daily: each evening after the market close, the clearinghouse calculates the net daily gain or loss on each open contract and immediately transfers cash between winning and losing accounts. This daily settlement eliminates the accumulation of unrealized losses. If daily losses cause an account to fall below maintenance margin, a formal margin call is generated, typically communicated via the broker before the next morning's open. For OTC derivatives cleared through a clearinghouse (as mandated post-Dodd-Frank for standardized swaps), a similar process applies, with variation margin calculated and called daily. For non-cleared OTC derivatives, margin calls are governed by the Credit Support Annex (CSA), with call amounts, eligible collateral types, thresholds, and minimum transfer amounts specified contractually.
Systemic margin call dynamics have been a feature of multiple financial crises. During the 1987 stock market crash, the S&P 500 futures market experienced such severe margin calls that some clearing members could not meet their obligations by the next morning, briefly threatening the integrity of the clearinghouse. The Federal Reserve's prompt intervention—guaranteeing bank lending to clearing members—prevented a clearinghouse failure. In August 1998 (LTCM crisis), simultaneous margin calls across multiple leveraged positions forced LTCM to liquidate in distressed markets, amplifying spread widening and creating contagion to other leveraged participants. In March 2020 (COVID selloff), volatility-related margin increases by CME and other exchanges forced widespread deleveraging across the hedge fund industry, contributing to one of the fastest 30% equity market declines in history.
For hedge fund managers, margin call management is a continuous liquidity risk management discipline. A well-managed hedge fund maintains a liquidity reserve—cash and near-cash assets not posted as margin—sufficient to meet potential margin calls across its full portfolio under a realistic adverse scenario. This is typically stress-tested by simulating the margin impact of a 3-standard-deviation adverse move in all positions simultaneously: what would be the total margin call, and does the fund have sufficient liquid assets to meet it without forced liquidation? Funds that cannot demonstrate this resilience in operational due diligence are increasingly screened out by institutional investors, who learned from 2008 that illiquidity risk is a material portfolio concern.
The decision-making process during a margin call is consequential for both short-term survival and long-term performance. Meeting a margin call in cash is straightforward if liquidity is available. If liquidity is insufficient, the fund must identify the most efficient liquidation—ideally selling the most liquid positions with the least market impact rather than being forced to sell positions indiscriminately. Some funds negotiate intraday margin extensions with their prime brokers, using credit facilities (revolving credit lines) as bridge liquidity. The worst outcome—forced liquidation by the broker at distressed prices—permanently destroys value and can trigger a cascade of additional losses as the forced selling moves prices against remaining positions.
Formula
Margin Call Amount = Initial Margin − Current Account Equity (when Current Equity < Maintenance Margin)
Example
A quantitative hedge fund holds a $200 million long position in S&P 500 E-mini futures (equivalent to approximately 890 contracts) as part of a beta hedging overlay, with $24 million in initial margin ($12,000 × 890 contracts) and $20 million in maintenance margin ($10,000 × 890 contracts) posted at CME. The fund holds $10 million in reserve liquidity (T-bills not posted as collateral). During a market selloff triggered by an unexpected Federal Reserve rate hike, the S&P 500 falls 3.5% in a single session—a decline of approximately 157 index points. Variation margin deducted: 890 contracts × $50 × 157 points = $6.99 million. Account equity falls to $24M − $6.99M = $17.01 million, below the $20M maintenance threshold. A margin call of $6.99 million (restoring the account to initial margin of $24M) is issued. The fund has $10 million in T-bills eligible as margin collateral, allowing it to meet the call without liquidating futures positions. If the T-bills had not been available, the fund would have been forced to liquidate approximately 140 contracts at distressed prices, reducing its position and crystallizing losses.
Related terms
Beta Class Of Options Clearing Contagion Credit Risk Credit Support Annex Deleveraging Dominant Future Equity Exchange Floor Forced Liquidation