Maintenance Margin Explained: Key Differences From Margin Accounts

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Maintenance margin is the minimum equity an investor must keep in a margin account, measured as a percentage of the current market value of the securities held, for as long as the leveraged positions stay open. In US securities accounts, FINRA sets the floor at 25% for long stock positions. Many brokers set house requirements of 30% to 40%, and higher for volatile or concentrated holdings. When equity falls below the requirement, the broker issues a margin call, and if the call is not met, it can sell positions to restore the account.

How maintenance margin works

A margin account lets you buy stocks, bonds or options partly with money lent by the broker, using the securities as collateral. Three rules apply at different points:

1. Account minimum. FINRA requires at least $2,000 in cash or securities before you trade on margin.
2. Initial margin. The Federal Reserve’s Regulation T lets you borrow up to 50% of the purchase price of eligible securities. Some brokers require a larger deposit.
3. Maintenance margin. Once you hold the position, your equity must stay at or above the maintenance percentage of the position’s current value. FINRA applies this throughout the trading day, not only at the close.

The requirement moves with the market. A $20,000 position needs at least $5,000 of equity at 25%. At $30,000 it needs $7,500, but equity has grown too, so the cushion usually widens. When prices fall, equity drops dollar for dollar while the loan stays the same, which is how accounts slip below the line.

Short positions carry stricter FINRA minimums. For stocks priced at $5 or more, the requirement is the greater of $5 per share or 30% of market value. For stocks under $5, it is the greater of $2.50 per share or 100% of market value.

Maintenance margin formula

The core test is:

Equity ÷ Market value of securities ≥ Maintenance margin rate

where Equity = Market value − Margin loan.

For a long position funded partly by a loan, the price at which a margin call is triggered is:

Call price = Loan ÷ (Shares × (1 − Maintenance rate))

This assumes a single position, no other cash or holdings, and ignores interest accruing on the loan, which slowly raises the effective trigger.

Worked example (hypothetical)

You buy 200 shares at $50, a $10,000 position. Under Reg T you deposit $5,000 and borrow $5,000. Your broker uses the 25% FINRA minimum.

• Call price: $5,000 ÷ (200 × 0.75) = $33.33. At that price, the position is worth $6,666.67, equity is $1,666.67, and 25% of $6,666.67 is exactly $1,666.67.
• Price falls to $30: position value is $6,000, equity is $1,000, and the requirement is $1,500. The shortfall is $500.

You have two main ways to cure that deficit:

• Deposit cash. Adding $500 lifts equity to $1,500 and meets the requirement.
• Sell shares. The proceeds repay the loan and the market value falls by the same amount, so a sale does not raise equity. It only lowers the requirement, by the maintenance rate times the amount sold. The sale needed is therefore Deficit ÷ Maintenance rate: $500 ÷ 0.25 = $2,000 of stock, or about 67 shares at $30. Afterward the position is worth $4,000, the loan is $3,000, and equity of $1,000 equals 25% of $4,000.

That multiplier explains why liquidation to meet a call often removes far more stock than the dollar size of the deficit. With a 40% house requirement, the same $500 shortfall would need only $1,250 of sales, but you would have received the call much earlier, at $5,000 ÷ (200 × 0.60) = $41.67.

How traders use it

Comparing the call price with the current price and the stock’s typical recent swings shows how much room a position has before a call. Traders who want a buffer borrow less than the maximum or keep extra cash in the account. Some place a stop-loss order above the call price to exit on their own terms, though a stop does not protect against gaps through the level.

Limitations

• The requirement is not fixed. Brokers can raise house requirements for a specific stock, a concentrated account or the whole firm without advance notice. They can go as high as 100%, which removes the stock’s loan value entirely.
• Liquidation is the broker’s choice. A broker may sell any securities in the account, choose which ones, and act before you respond to a call. You are not entitled to a warning or an extension.
• Losses can exceed your deposit. If prices gap down past the call level, selling may not cover the loan, and you owe the rest.
• Interest keeps running. Accruing interest reduces equity over time even when prices are flat.

Maintenance margin vs. related terms

Margin account vs. maintenance margin. The margin account is the borrowing arrangement itself, created by a signed agreement with the broker. Maintenance margin is one rule inside that arrangement, the equity floor that applies while positions are open.

Initial margin vs. maintenance margin. Initial margin (50% under Reg T) controls entry. Maintenance margin (25% minimum) controls whether you can keep the position. Failing to fund an initial purchase triggers a Reg T or “federal” call. Falling below the maintenance level triggers a maintenance call, covered in what a margin call is.

Futures maintenance margin. In futures, margin is a performance bond rather than a loan, and exchanges set initial and maintenance levels per contract. If equity falls below maintenance, you must usually deposit enough to return to the initial level, not just to the maintenance line.

Forex margin level. Retail forex and CFD brokers express the same idea as a margin level: equity ÷ used margin × 100. Each broker sets its own margin call and stop-out percentages and closes positions automatically at stop-out. A position size calculator helps size trades so a normal adverse move does not reach that level.

The Bottom Line

Anyone borrowing from a broker to hold stocks should know where a margin call would hit. Calculating the call price and comparing it with the stock's typical swings shows how much room a position has. Borrowing less than the maximum or keeping extra cash builds a buffer, because a broker can liquidate on its own terms and a gap down can leave you owing more than you deposited.