Naked Option Margin Estimator (Reg-T)
Initial margin for a naked short put or call under the standard Reg-T 20%/10% formula brokers apply.
Formula
Reg-T margins are the broker minimum — portfolio-margin accounts often need far less, and brokers may demand more in volatile names. The premium-to-margin ratio annualized is the honest yield of naked selling; it shrinks fast as the option goes ITM.
Not financial advice — for informational and analytical use only. Verify all figures with a qualified professional before acting on them.
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.
Need naked option margin estimator results fast? Analysts, founders, traders and finance professionals use the Naked Option Margin Estimator to skip the spreadsheet and get a defensible answer in one step — free, private and instant.
About Naked Option Margin Estimator (Reg-T)
Initial margin for a naked short put or call under the standard Reg-T 20%/10% formula brokers apply. Reg-T margins are the broker minimum — portfolio-margin accounts often need far less, and brokers may demand more in volatile names. The premium-to-margin ratio annualized is the honest yield of naked selling; it shrinks fast as the option goes ITM. The governing relationship is margin = max(20%·S − OTM + prem, 10%·K + prem) × 100. The Naked Option Margin Estimator computes entirely in your browser — free, private (your figures never leave your device) and instant, recalculating live as you change any input.
How to use Naked Option Margin Estimator (Reg-T)
- 1Enter Short option type, Underlying price, Strike, Premium received, Contracts (×100) into the Naked Option Margin Estimator.
- 2The result is computed automatically using margin = max(20%·S − OTM + prem, 10%·K + prem) × 100 — there is no button to press.
- 3Change any input to model a different scenario, then copy or share the result.
Why use Naked Option Margin Estimator (Reg-T)?
- ✓Computes naked option margin estimator instantly with the correct formula — no spreadsheet needed
- ✓100% free and unlimited, with no sign-up, login or paywall
- ✓Runs entirely in your browser, so the figures you enter stay private
- ✓Shows the formula, a live worked example and references so you can defend the number
Frequently asked questions
What is the formula behind the Naked Option Margin Estimator?+
Naked Option Margin Estimator uses margin = max(20%·S − OTM + prem, 10%·K + prem) × 100. Reg-T margins are the broker minimum — portfolio-margin accounts often need far less, and brokers may demand more in volatile names. The tool substitutes your actual inputs into this relationship and shows the worked example step by step.
What inputs does the Naked Option Margin Estimator need?+
Enter Short option type, Underlying price, Strike, Premium received, Contracts (×100) and the result updates immediately — there is no button to press. Change any value to model a different scenario in real time.
Is the Naked Option Margin Estimator free, and is my data private?+
Yes — it is completely free with no sign-up or usage limit, and it runs entirely in your browser, so the numbers you enter are never uploaded or stored on any server. It is for informational and analytical use, not financial advice.
What should I watch out for when using the Naked Option Margin Estimator?+
The premium-to-margin ratio annualized is the honest yield of naked selling; it shrinks fast as the option goes ITM.
What is the Naked Option Margin Estimator based on?+
The method follows authoritative sources: FINRA Rule 4210 — option margin requirements. The formula and references are shown on the page so you can verify and cite the result.
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