Free tool
Enter a long or short position to see the loan or credit balance, your equity, whether a maintenance call exists, and the stock price that would trigger one.
Built for FINRA SIE exam prepEnter a price, share count and current price.
Margin math is a favorite SIE topic. Encodr turns the formulas into spaced-repetition practice so they hold until exam day.
Get started freeLong. Buy $20,000 of stock at 50% initial margin: you deposit $10,000 and the debit balance is $10,000. If the market value falls to $12,000, equity is 12,000 - 10,000 = $2,000. At a 25% maintenance requirement the firm needs 0.25 x 12,000 = $3,000, so the call is $1,000. A call is triggered when the market value drops below debit / (1 - maintenance), here $13,333.33.
Short. Sell short 100 shares at $40: proceeds are $4,000, the 50% deposit is $2,000 and the credit balance is $6,000. If the stock rises to $50, the market value is $5,000 and equity is $1,000. The requirement is the greater of 30% of market value ($1,500) or $5.00 a share ($500), so the call is $500.
Regulation T sets the initial requirement and FINRA Rule 4210 sets maintenance; both figures shown are as of 2026, check your firm, and a firm may require more. The short-stock trigger price here uses the percentage and the $5.00 a share floor. This tool is for study only, and is not investment advice.
Related prep: the FINRA SIE course page, SIE exam math formulas with examples and the bond yield calculator.
For a long position, equity is the current market value minus the debit balance (the money borrowed). For a short position, equity is the credit balance minus the current market value of the shorted stock.
When equity falls below the maintenance requirement. Exactly at the requirement is not a call. The FINRA minimum is 25 percent of market value for long stock and 30 percent for short stock as of 2026, and a firm can set a higher house requirement.
Regulation T sets the initial requirement, 50 percent of the purchase as of 2026. FINRA Rule 4210 sets the maintenance requirement. They come from different rules, and both are editable in this calculator.
No. It covers a single position held in a margin account. Day trading margin is a separate topic and the rules have changed recently, so check your firm and the current FINRA notice.
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