US Options Margin Calculator

Calculate approximate margin requirements for US equity options under Reg T rules. Actual broker requirements may differ. For illustrative purposes only.

Option Type

Position

Underlying Price

10.005000.00

Strike Price

10.005000.00

Option Premium (per share)

0.10200.00

Number of Contracts

1100

Naked call margin under Reg T rules.

Margin Estimate

Margin Required

$9,200

Premium

$1,200

Notional Position Value$45,000

Disclaimer

This calculator is for educational and illustrative purposes only. It does not constitute financial, investment, or tax advice. Results are estimates based on the inputs you provide and may not reflect actual returns. Consult a qualified financial advisor before making any investment decisions.

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Frequently Asked Questions

SPAN (Standard Portfolio Analysis of Risk) is a margin system developed by the CME Group that calculates margin requirements based on the overall risk of a portfolio. It considers various scenarios of price changes and volatility to determine the minimum margin needed.

Regulation T, set by the Federal Reserve, governs the amount of credit brokers can extend. For options, Reg T sets the initial margin requirement — typically 50% for stock purchases. Options writers (sellers) may need to deposit additional margin based on the underlying stock price and option premium.

A margin call is triggered when your account equity falls below the maintenance margin requirement (typically 25% under FINRA rules, though brokers often set higher levels). Short option positions are marked to market daily, and unfavorable price movements can trigger margin calls.

Initial margin is the amount required to open a position (50% under Reg T for most equities). Maintenance margin is the minimum equity you must maintain after the position is open (25% under FINRA, often 30-40% at most brokers). If your equity drops below maintenance, you receive a margin call.

Buying options (long calls or long puts) requires paying the full premium upfront and does not require margin. However, writing (selling) options, particularly uncovered/naked options, requires significant margin because of the potentially unlimited risk.