Distinct from margin interest cost — this finds the exact price at which a broker would require additional cash or securities to meet the maintenance margin requirement.
How it works
The initial margin requirement determines how much was borrowed per share. Dividing that loan amount by one minus the maintenance margin requirement gives the exact price at which the account’s equity percentage would fall to the maintenance minimum.
What this does not include
This computes FINRA’s regulatory minimum framework — individual brokers often set higher “house” maintenance requirements than the regulatory minimum, which would trigger a call at a higher price than this calculator shows.
How to use this calculator
- Enter the purchase price, initial margin requirement, and maintenance margin requirement.
A worked example
A stock purchased at $100 with 50% initial margin and a 25% maintenance margin requirement: margin call price = $66.67 — the price at which the position’s equity ratio drops to the maintenance threshold.
What the variables mean
| Variable | Meaning |
|---|---|
| Purchase price | Price paid per share when the position was opened |
| Initial margin % | Percentage of the purchase price paid with the investor’s own funds |
| Maintenance margin % | Minimum equity percentage the broker requires to avoid a margin call |
Edge cases worth knowing
A margin call happens well before the position reaches zero. The stock only needs to fall to the calculated threshold — a third of the way down in this example — not all the way to worthless, before the broker demands more funds or liquidates the position.
A maintenance margin at or above the initial margin makes the calculation invalid — that combination would trigger an immediate call, which the calculator declines to show a result for.
Frequently asked questions
What happens when a margin call is triggered?
The broker requires the investor to deposit additional cash or securities, or sell positions, to bring the account back up to the maintenance margin requirement — often within a very short timeframe.
What is FINRA’s minimum maintenance margin requirement?
25% of the total market value of margined securities, though many brokers require a higher house minimum for additional cushion.
Can a broker sell positions without notice during a margin call?
Yes — brokers generally reserve the right to liquidate positions without prior notice if an account falls below the maintenance requirement, regardless of any grace period typically offered.
