💳 Stock Margin & Buying Power Calculator
Calculate your maximum leverage, margin loan borrowing capacity, financing interest, and the exact stock price drop that triggers a broker margin call.
Position Health & Liquidation Price
Moderate MarginDownside Stress Test Simulation
See how price drops impact your remaining account equity and whether a broker liquidation is triggered.
| Market Drop | Stock Price | Position Value | Remaining Equity | Equity Ratio % | Account Status |
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Understanding Margin Mechanics & Forced Liquidation
Trading on margin allows you to purchase securities using cash borrowed from your broker. While leverage amplifies gains on winning trades, it accelerates losses symmetrically. A 50% drop in a 2x leveraged position entirely wipes out 100% of your starting capital.
FINRA Rule 4210 Maintenance Margin
Federal law requires at least 25% equity in margin accounts. However, most retail brokers (Interactive Brokers, Schwab, Robinhood) impose 'house requirements' of 30% to 50% on volatile equities and 100% (no margin allowed) on meme stocks, leveraged ETFs, or penny stocks.
The Forced Liquidation Danger
Brokers are not required to give you 24 hours to meet a margin call. In volatile conditions, algorithmic risk engines sell shares automatically at market prices to guarantee the broker recoups their loan principal before equity goes negative.
Frequently asked questions
How is the stock margin call price calculated?
The margin call price is calculated using the formula: Margin Call Price = Borrowed Amount / [Number of Shares × (1 - Maintenance Margin %)]. For example, if you borrow $10,000 to purchase 200 shares with a 25% maintenance requirement, your margin call triggers at $10,000 / [200 × 0.75] = $66.67 per share.
What is the difference between initial margin and maintenance margin?
Initial margin (Federal Reserve Regulation T) dictates that you must deposit at least 50% of the purchase price when entering a stock position. Maintenance margin (FINRA Rule 4210) requires you to keep at least 25% equity in the position at all times after purchase, though many retail brokers require 30% to 40%.
What happens if a margin call is triggered?
When your account falls below the maintenance margin requirement, the broker issues a margin call requiring an immediate cash deposit. If funds are not provided immediately, the broker has the contractual right to liquidate your shares at current market prices without prior notice.
How does day trading buying power differ from overnight buying power?
Standard Regulation T allows 2:1 leverage (overnight buying power = 2× equity). Pattern Day Traders (PDTs) maintaining at least $25,000 in equity are granted 4:1 intraday buying power (4× equity) for positions opened and closed within the same trading session.
Can you lose more money than your initial deposit using margin?
Yes. If an equity holding suffers a catastrophic overnight gap down (such as an unexpected bankruptcy or fraud scandal), the shares can plummet well below your borrowed loan balance, leaving you legally indebted to your brokerage firm for the deficit.