In trading, margin is cash, securities, or other collateral required to finance or support a leveraged position.
In trading, margin is cash, securities, or other collateral required to finance or support a leveraged position. In a securities margin account, margin supports credit extended by a broker. In futures markets, margin is generally a performance bond rather than a partial payment for the contract’s underlying value.
Margin limits leverage and protects brokers, clearing firms, and clearinghouses against counterparty losses. It does not protect the trader from market losses, guarantee that a position can remain open, or cap the amount that may be owed after liquidation.
| Margin concept | What it supports | Main financial effect |
|---|---|---|
| Securities initial margin | A securities purchase or other opening transaction in a margin account | Determines how much investor equity is needed at entry |
| Securities maintenance margin | An open securities position after prices change | Can trigger a Margin Call or liquidation |
| Futures initial margin | Performance collateral for a futures position | Supports daily settlement obligations; it is not a loan down payment |
| Variation margin | Cash flow arising from mark-to-market gains and losses | Moves funds as positions are revalued |
| Portfolio margin | Risk-based requirement considering offsets and portfolio exposure | Can differ materially from simple position-by-position rules |
| House margin | A broker or clearing firm’s own requirement | May exceed external minimums and change with risk conditions |
A securities Margin Account allows a broker to lend cash against eligible account assets. The investor contributes equity, the broker provides credit, and account securities secure the debit balance.
For a simplified long-stock account:
1account equity = current market value - margin debit
2equity percentage = account equity / current market value
3required equity = applicable margin percentage x current market value
These equations are only a starting point. A broker calculation can also reflect short positions, options, concentrated holdings, unsettled transactions, open orders, accrued interest, security eligibility, portfolio offsets, and house rules.
Assume an investor buys $20,000 of eligible stock using $12,000 of cash and an $8,000 margin debit.
$20,000$8,000$20,000 - $8,000 = $12,000$12,000 / $20,000 = 60%If the stock falls to $12,000, the debit remains $8,000 before interest, so equity falls to $4,000 and the equity percentage falls to 33.3%. The stock declined 40%, but the investor’s equity declined 66.7%. Whether the account is deficient depends on the applicable maintenance and house requirements.
Initial margin is the equity or collateral required before a leveraged position is opened. The term is not one universal percentage. Its calculation depends on the product, position direction, strategy, account type, venue, broker, clearing arrangement, and jurisdiction.
For U.S. securities credit, Federal Reserve Regulation T governs extensions of credit by brokers and dealers and imposes initial-margin and payment rules on certain securities transactions. FINRA, exchanges, and brokerage firms can impose additional requirements. Futures exchanges, clearinghouses, and futures commission merchants use different performance-bond frameworks.
A quoted initial-margin percentage should therefore be tied to a dated rule, product, account, and broker record. A percentage copied from a general article is not sufficient evidence for a live trade.
Maintenance margin is the equity or collateral that must remain after a position is open. It matters because market losses reduce equity while the loan or contractual exposure can remain.
For a simplified long-stock position with fixed debit D and maintenance percentage m, the market value at which equity equals the requirement can be expressed as:
1maintenance threshold value = D / (1 - m)
If the debit is $8,000 and the illustrative maintenance percentage is 35%, the simplified threshold is approximately $8,000 / 0.65 = $12,307.69. Actual calls can occur at a different level because real accounts contain other positions, interest, transactions, and house adjustments.
Futures margin is generally performance collateral. The trader is not borrowing the remaining notional value of the contract from the broker. Instead, initial margin supports the obligation, positions are marked to market, and adverse changes can require variation margin or additional collateral.
This distinction matters when comparing leverage. A futures contract can create large market exposure relative to posted collateral, but the collateral is not the purchase price of the underlying commodity or financial instrument. Daily settlement, contract multipliers, price limits, liquidity, and changing margin requirements affect cash needs.
Options, cleared swaps, security futures, and portfolio-margin accounts have product-specific systems. Do not apply a stock-margin percentage to a derivatives position without confirming the governing methodology.
| Concept | Difference from trading margin |
|---|---|
| Profit margin | Accounting ratio comparing profit with revenue; not trading collateral |
| Haircut | Discount applied to collateral value or financing proceeds; can affect margin capacity |
| Down payment | Partial purchase payment that builds ownership; futures margin is not a down payment |
| Margin loan | Cash credit extended by a broker against account assets |
| Borrow fee | Cost of borrowing securities for a short sale, separate from interest on borrowed cash |
| Collateral | Property supporting an obligation; margin is a required amount or process involving collateral |
This page is educational and does not recommend using leverage or determine whether a margin strategy is suitable. Current requirements and account rights must be confirmed with the broker, exchange, clearing firm, and applicable rules before a financial decision.
The SEC’s Investor Bulletin: Understanding Margin Accounts explains securities margin accounts, margin loans, liquidation rights, interest, and the risk of losing more than the amount initially invested.
The Federal Reserve publishes Regulation T, which governs credit by brokers and dealers, including initial-margin and payment rules for covered securities transactions. FINRA Rule 4210 addresses margin requirements for FINRA members and multiple product and account categories.
The CFTC’s futures market overview explains that futures margin is a performance bond rather than a stock-style down payment and describes initial, maintenance, and variation margin at a high level.