FINRA Margin Maintenance
The Formal Definition
The statutory minimum equity percentage that a retail margin account must maintain at all times under FINRA Rule 4210—stipulating that investor equity must equal at least 25% of the total current market value of all long margin securities.
Minimum Account Equity ($) ≥ Total Market Value of Long Margin Positions × 0.25 (House Requirements Often 30% - 50%)
Cole Barrett's Reality Check
The Unvarnished Bottom Line"FINRA Rule 4210 sets the legal floor at 25% equity, but don't assume your broker will give you that much breathing room. Most brokers enforce 'house requirements' of 30%, 40%, or even 100% on volatile stocks without warning. If your equity drops by a single dollar below their house threshold, they will liquidate your positions without picking up the phone."
Interactive Simulator: Test the Math
Real-World Example: Scenario Breakdown
Examining the real numbers for: An account holding $100,000 in equities backed by a $50,000 margin loan during a broad market pullback
| Execution Metric | Prudent Margin Manager (Low Leverage) | Over-Leveraged Retail Account |
|---|---|---|
| Fee / Rate | $0 account fees | $0 account fees |
| Spread / Buffer | Maintained an 80% equity cushion; kept total margin borrowing below 20% of net account value | Borrowed the legal maximum ($50,000 loan against $100,000 in assets; 50% initial equity ratio) |
| Execution / Status | Market experienced a 20% drop; account equity easily stayed far above FINRA and house maintenance minimums | Portfolio dropped 35% to $65,000; equity fell to $15,000 (23.0%), breaching FINRA’s statutory 25% threshold |
| Total Cost / Result | Avoided forced liquidations through conservative position sizing | Suffered catastrophic forced liquidations at market lows |
How Brokers Weaponize This Term
Always check your broker's specific 'House Maintenance Requirements' for each stock you hold. While blue-chip companies typically sit at the 25% FINRA statutory minimum, popular growth stocks and leveraged ETFs often have house requirements of 50% to 100%, making them vulnerable to margin calls.
Broker Evaluation Matrix
Cole Approves
Interactive Brokers: Provides institutional Portfolio Margin accounts with dynamic risk-based haircuts, transparent real-time margin alerts, and low borrowing rates.
Read Audit →Cole Flags / Avoids
High-Interest Retail Platforms: Charges high margin interest rates (12%+) and maintains aggressive automated liquidation algorithms that sell off client assets without warning.
View Trap Details →Frequently Asked Questions
Does a broker have to give me 24 hours to meet a margin call?
No. Under standard margin agreements, brokers have the legal right to liquidate your positions immediately without notice if your account breaches maintenance levels.
What is the difference between initial margin and maintenance margin?
Initial margin (Regulation T) is the equity percentage required to open a new position (typically 50%). Maintenance margin (FINRA Rule 4210) is the equity percentage required to keep the position open (minimum 25%).