Margin debt is the amount borrowed from a broker in margin accounts, used to measure individual leverage and aggregate market borrowing.
Margin debt is the amount an investor has borrowed from a broker in a margin account. At the account level, it is the debit balance that must be repaid; at the market level, aggregate margin debt is often watched as one indicator of leveraged investor exposure.
Margin debt matters because the loan balance does not automatically fall when securities decline. A high debt balance can reduce the investor’s equity cushion and increase the chance of a margin call or forced sale.
An investor owns $50,000 of marginable securities and has a $15,000 margin debit balance. Before accrued interest and other adjustments, account equity is $35,000.
If the securities fall to $40,000, the debt is still $15,000, so equity falls to $25,000. The broker then compares the account to current maintenance and house requirements. If the cushion is too small, the account may receive a margin call or face liquidation.
| Use | What it measures | Limitation |
|---|---|---|
| Individual account | Amount one customer owes the broker | Does not show risk without collateral, equity, and requirement data |
| Broker risk monitoring | Customer debit balances and margin exposure | Depends on firm-specific collateral and risk controls |
| Market-level analysis | Reported margin borrowing across firms | Can rise with market values and activity, not only speculation |