A margin call requires additional equity, collateral, or exposure reduction after an account falls below an applicable margin requirement.
A margin call requires a customer or clearing participant to add equity, provide eligible collateral, reduce exposure, or otherwise correct a margin deficiency. It occurs when an account no longer satisfies an applicable maintenance, house, exchange, clearing, or risk-based requirement.
Despite the name, a margin call is not necessarily a telephone call or a guaranteed grace period. Depending on the agreement and rules, a broker may restrict transactions or sell account assets without waiting for the investor to choose what to sell.
| Requirement | When it applies | Primary question |
|---|---|---|
| Initial margin | When a position or strategy is opened | Is enough equity or collateral available to establish exposure? |
| Maintenance margin | While the position remains open | Does the account still contain enough support after prices and requirements change? |
| House margin | Under the broker or clearing firm’s own risk policy | Is additional support required beyond an external minimum? |
| Variation margin | As marked-to-market derivatives gains and losses settle | What cash or collateral must move because the position changed value? |
The opening requirement does not guarantee that the account can withstand a later loss. Maintenance and house requirements can be calculated differently, and the broker can apply higher requirements to concentrated, volatile, illiquid, or hard-to-borrow positions.
For one long securities position with market value V and fixed margin debit D:
1account equity = V - D
2equity percentage = (V - D) / V
3required equity = maintenance percentage x V
4cash deficiency = max(0, required equity - account equity)
Assume the account holds stock worth $12,000, has an $8,000 debit, and is subject to an illustrative 35% maintenance requirement.
$12,000 - $8,000 = $4,000$4,000 / $12,000 = 33.3%35% x $12,000 = $4,200$4,200 - $4,000 = $200A $200 cash deposit applied to the debit would raise equity to $4,200 under this simplified example. Selling stock and using the proceeds to reduce the debit does not add equity before costs; it reduces both market value and debt. The approximate sale needed is therefore larger:
1required sale = market value - (account equity / maintenance percentage)
2required sale = $12,000 - ($4,000 / 35%) = approximately $571.43
Real broker calculations may include other holdings, concentration charges, open orders, settlement items, interest, short positions, option requirements, minimum dollar rules, and liquidation increments. The example is instructional, not a call estimate for a live account.
For the same simplified long position, the market value at which equity equals the maintenance requirement can be estimated as:
1threshold market value = margin debit / (1 - maintenance percentage)
With an $8,000 debit and a 35% illustrative requirement, the threshold is approximately $8,000 / 0.65 = $12,307.69. The related share price depends on the number of shares held.
This threshold is not a guaranteed warning point. Accrued interest raises the debit, a house requirement can change, and a market gap can move the position below the threshold before action is possible.
The account can become deficient even when a specific position has not declined. A requirement increase or collateral reclassification can create the call.
| Action | Account effect | Important limitation |
|---|---|---|
| Deposit cash | Increases equity or reduces debit | Funds must arrive and be accepted in time |
| Transfer eligible securities | Adds collateral value | Full market value may not count toward margin |
| Sell long positions | Reduces assets and can reduce the debit | Required sale can exceed the cash deficiency; price and taxes matter |
| Buy to cover short positions | Reduces short exposure and related requirement | Price can rise further and borrow may be recalled |
| Close options or spreads | Removes some risk and requirements | Legs may be illiquid or closing can remove an offset first |
| Broker liquidation | Firm selects and closes positions | Investor may not control timing, order, price, or tax outcome |
A broker can determine that immediate liquidation is needed even if another response was discussed. The margin agreement and applicable rules should be read before relying on any call period.
A securities call often relates to account equity supporting a broker loan or position requirement. A futures call generally relates to performance collateral and mark-to-market settlement. Adverse futures changes debit the account, and funds may be required to restore it to the applicable level.
| Feature | Securities margin account | Futures margin account |
|---|---|---|
| Core arrangement | Broker credit and collateralized securities positions | Performance bond supporting contract obligations |
| Main changing item | Securities value, debit, eligibility, and requirement | Daily settlement gains or losses and changing performance-bond requirement |
| Typical response | Deposit assets, reduce debit, or liquidate securities | Deposit funds or close futures exposure |
| Key misconception | Call must precede liquidation | Margin is a partial purchase payment |
Options, security futures, portfolio margin, and cleared or uncleared derivatives have their own methodologies. The product and account documentation must be identified before applying a formula.
| Feature | Margin call | Stop-loss order |
|---|---|---|
| Trigger | Account or position fails a collateral requirement | Market reaches an order trigger |
| Main purpose | Protects broker or clearing credit and counterparty exposure | Attempts to manage a selected position’s market loss |
| Decision maker | Firm rules and agreement can control liquidation | Investor sets the order instruction |
| Execution uncertainty | Firm may sell any permitted assets | Stop price is not a guaranteed execution price |
| Account coverage | Can reflect the entire account or portfolio | Usually applies to a specified position or quantity |
A stop order can fail to execute near its trigger in a gap or illiquid market. It also may not account for losses, interest, or requirement changes elsewhere in the account.
This page is educational and does not recommend a response to a live margin call. A live deficiency requires the broker’s current calculation, the account agreement, liquidity facts, and professional advice where legal, tax, or financial consequences matter.
The SEC’s Investor Bulletin: Understanding Margin Accounts states that margin-account investors can be required to add assets on short notice and that firms may sell securities without consulting them under the account arrangement.
Investor.gov’s Margin Call glossary entry summarizes the risk that a firm can demand assets or sell account securities and can change the threshold at which a call applies. FINRA Rule 4210 contains detailed member margin requirements across multiple account and product types.
For futures, the CFTC’s futures market overview explains initial, maintenance, and variation margin and daily mark-to-market at a high level.