A "Margin Call" is perhaps the most dreaded phrase in an investor's vocabulary. It is the mechanism by which a broker protects itself from your potential losses. When the value of your account drops too low, the broker "calls" in the debt, demanding that you either add more collateral or reduce your debt immediately .

What Triggers a Margin Call?

There are three primary triggers for a margin call:

Market Depreciation: The value of the stocks you hold as collateral drops, causing your equity percentage to fall below the maintenance requirement (e.g., below 25%) .
Over-Leveraging: You attempt to buy more than your current buying power allows .
Requirement Changes: Your broker increases the "house" maintenance requirement (e.g., moving it from 25% to 35%), suddenly making your current equity insufficient .

The Anatomy of a Margin Call

When a margin call is triggered, you are required to bring your equity back up to the maintenance level. You generally have a very short window to act—sometimes just a few days, but in volatile markets, the broker can demand action immediately .

How to Satisfy a Margin Call

There are three ways to fix a margin call :

Deposit Cash: You can transfer money from your bank account to your brokerage account.
Deposit Securities: You can move marginable stocks from another brokerage account into the one facing the call.
Sell Securities: You can sell some of your current holdings. The proceeds from the sale go toward paying down the margin loan, which reduces your debt and increases your equity percentage.

The Math of the Call

Satisfying a margin call isn't always a 1-to-1 ratio. If you have a $1,000 margin call, simply selling $1,000 worth of stock might not be enough to fix the ratio.

Formula for Selling to Meet a Call:

Value to Sell = Margin Call Amount / Maintenance Requirement %

If you have a $6,000 margin call and your maintenance requirement is 40% (0.40):

$6,000 / 0.40 = $15,000.
You would need to sell $15,000 worth of stock to satisfy a $6,000 call .

Formula for Depositing Securities to Meet a Call:

Value to Deposit = Margin Call Amount / (1 - Maintenance Requirement %)

If you have a $6,000 margin call and the stock you are depositing has a 40% requirement:

$6,000 / (1 - 0.40) = $10,000.
You would need to deposit $10,000 worth of that stock to satisfy the call .

The Danger of Forced Liquidation

If you do not meet a margin call in time, or if the market is moving so fast that your account equity is evaporating, the broker will engage in "Forced Liquidation."

This is the most brutal aspect of margin trading. The brokerage firm has the right to sell your securities without your permission to cover the loan . They do not have to consult you on which stocks to sell; they will often sell the most liquid (easiest to sell) positions, which might be the stocks you wanted to keep for the long term. Furthermore, they can charge you a commission for these forced trades, adding insult to injury .

Important Realities of Margin Calls :