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Implied Volatility (stocks)
Implied volatility is expected future volatility of the option’s underlying at expiration, reflected in the current option premium. It is not historical volatility and not a formula this page invents.
Implied volatility is a measure of the expected future volatility of the option’s underlying security at expiration, reflected in the current option premium. It is not historical volatility and not a squeeze signal on the stock.
That sentence is OCC SRO language, not a DennTech forecast. SEC Release No. 34-86731 (File No. SR-OCC-2019-005) is Options Clearing Corporation rule text for the Vanilla Option Model and Smoothing Algorithm inside STANS, OCC’s methodology for calculating margin requirements. It is not a retail glossary.
OCC 34-86731: priced in the premium, used in margin models
The filing: the implied volatility of an option is a measure of the expected future volatility of the option’s underlying security at expiration, which is reflected in the current option premium in the market. Given the current market price of a plain vanilla option, OCC uses its algorithms to estimate that implied volatility. OCC relies on the Vanilla Option Model to generate theoretical values, implied volatilities, and certain risk sensitivities for plain vanilla listed options. A second STANS component, the Smoothing Algorithm, estimates fair prices of listed option contracts based on their bid and ask price quotes.
Those are clearinghouse objects. You don't send them as a ticket, and we don't reprint their formulas. Read the options chain as the quote surface the premium comes from. Because the input is a market price, the bid-ask spread matters: a vendor that inverts the mid is using a midpoint, not a fill.
OIC IV vs HV tool (20-minute delay)
The Options Industry Council hosts a Historical and Implied Volatility tool (powered by iVolatility) on its quotes-and-calculators page. The tool compares a security’s historical volatility with the 30-day implied volatility of the options. It summarizes volatility information over the last year and can show a one-year historical-volatility versus implied-volatility chart. All data is provided with a 20-minute delay. OCC states the tools are educational only and makes no representation as to timeliness, accuracy, or validity.
Historical volatility is a different object: past underlying price change over a window you specify. OCC/OIC language does not turn that comparison into a trading system, a reversion rule, or a win rate. If you compute HV, write the window. If you did not, you do not have HV.
Events change priced vol. They do not give you a number.
A known calendar (an earnings report, a scheduled macro print) can lift demand for options and lift displayed premiums, which lifts implied volatility into the event. After the print, that extra premium can come out. Event risk is still gap risk on the underlying. Session clocks for the cash market are on U.S. stock market session hours 2026. Early 4:00 a.m. versus 7:00 a.m. is an exchange split. Overnight 9:00 p.m.–4:00 a.m. ET is planned for December 6, 2026, not live. Do not mix those clocks with Cboe C1 equity-options GTH (TBA).
Do not treat a high IV label as a named squeeze event, as short interest, or as a reason to skip position sizing. IV rank and IV percentile, when a platform shows them, are that platform’s normalization of current IV against a history it defines. They are not on the OPRA chain as official fields, and they are not DennTech numbers. Greeks around the invert live in The Greeks & Options Pricing after Stock Options Fundamentals.
IV vs HV vs a forecast (legend only)
Classification only. No implied-volatility percentage, no historical-volatility percentage, no index level.
| Measure | What it is | What it is not |
|---|---|---|
| Implied volatility | Expected future vol of the underlying, reflected in the current option premium (OCC 34-86731) | A stock series, a DennTech forecast, IV rank, or a closed-form formula |
| Historical volatility | Past underlying price change; OIC tool compares it to 30-day IV on a 20-minute delay | |
| Your forecast | A thesis you write and size | The chain, OPRA, OCC, or OIC |
Size the underlying the same way you size any stock: example only, $10,000 account, 1% dollar risk, $1.50 per-share stop → 66 shares, round down. Premium risk on a long option is still a real budget line. The risk calculator is a crypto UI; treat the unit as shares, round down.
FAQ
What does OCC 34-86731 say implied volatility is?
A measure of the expected future volatility of the option’s underlying security at expiration, reflected in the current option premium. Given the current market price of a plain vanilla option, OCC uses its algorithms to estimate that IV. The filing is SRO margin-model text, not a retail how-to.
What is the OIC IV versus HV tool?
An educational OIC tool (20-minute delay) that compares a security’s historical volatility with the 30-day implied volatility of the options.
Do you publish IV rank or a closed-form IV formula?
No. OCC describes algorithms inside STANS.
Is high implied volatility a squeeze?
No. This is not a squeeze page. Elevated IV means listed options are pricing more expected variability in the underlying. It is not short interest and not a reason to skip a stop.
Do stocks themselves have implied volatility?
The OCC sentence attaches IV to an option’s underlying via the option premium. The number you read is from listed options on that name, off the chain, not a stock last-sale series.
Educational only. Not financial, tax, or legal advice. IV language follows OCC Release No. 34-86731 (SRO text) and the OIC Historical and Implied Volatility tool (20-minute delay). Trading stocks and listed options can result in loss of capital, including premium paid and short-option losses larger than premium received.