Maintenance margin is the minimum equity requirement for keeping a leveraged position open. Falling below the applicable threshold may trigger a margin call, restrictions on new positions, partial liquidation, or forced closure depending on the product, venue, and broker rules.
How it works
Account equity (cash balance plus or minus unrealized floating P&L) is continually monitored against maintenance margin formulas.
If equity falls below the applicable maintenance threshold, broker risk procedures activate, which may include margin calls, new position restrictions, partial liquidation, or forced closure.
Why it matters
Maintenance margin helps prevent client accounts from sinking into negative equity balances during rapid market declines.
It represents a regulatory and broker risk boundary, highlighting the importance of setting risk stops well ahead of liquidation levels.
A simple market example
An investor buys $100,000 of stock using $50,000 cash and $50,000 margin debt. The broker imposes a 25% maintenance margin requirement ($25,000). If the portfolio value drops to $70,000, equity drops to $20,000 ($70k - $50k debt), breaching the $25,000 requirement and prompting margin action by the broker.
Common mistakes
Setting stop losses directly at the maintenance margin line rather than well ahead of it, guaranteeing maximum possible financial loss.
Ignoring the difference between initial margin (required to enter) and maintenance margin (required to maintain positions).
Frequently asked questions
Does the broker give a grace period to deposit funds during a maintenance margin breach?
In traditional equities, brokers may issue a margin call providing a designated deposit window depending on regulatory framework. In derivatives and fast-moving markets, brokers may enforce accelerated or automated procedures to protect against deficit balances.
Who pays the execution fees during a maintenance margin liquidation?
The trader pays all execution commissions, plus any additional liquidation penalty or administrative fees charged by the broker.
Can a maintenance margin breach lead to debt beyond initial capital?
Yes. In severe gap openings or illiquid market flash crashes, the final liquidation fill price may exceed total deposited capital, creating a negative balance.
Educational content only. Definitions describe common market usage and may vary by jurisdiction, instrument, or institution.