Implied Volatility vs Historical Volatility: What Options Traders Need to Know

Learn the difference between implied volatility vs historical volatility and how options traders can use IV and HV to evaluate premiums and risk.

Why Volatility Matters in Options Trading

When you are involved in options trading, volatility is one of the figures you must not ignore. While the current price of the underlying stock shows you where the stock is, volatility provides another element of the picture by indicating how much the market has moved or how much movement is built into the options. This is important since the premium of an option is affected by a number of factors, such as the price of the underlying asset, the strike price, the expiration date, interest rates,…

What Is Implied Volatility?

Implied volatility is the level of volatility that is implied by an option's present market price. To put it simply, the market price of an option reflects the degree of price movement that traders are incorporating into the contract. A pricing model can calculate the volatility figure which makes the model's theoretical price equal to the actual market price by using the option price and other known inputs. It is therefore unlike merely assessing how much a stock has moved in the past; it is so…

How IV Affects Option Premiums

All other things being equal, a higher level of IV usually increases an option's extrinsic value, while a lower level of IV usually reduces it. Likewise, Charles Schwab's present educational material states that higher IV generally increases option premiums since it raises the extrinsic value. The situation is particularly important for those people who sell options. If a trader is acting as a cash-secured put seller or a covered call writer, they should not only take into account the premium th…

What Is Historical Volatility?

Historical Volatility (HV) is a measure of the actual movement of the underlying asset over a certain historical period; it is calculated from past price returns, typically employing a statistical method such as standard deviation, and is generally annualized so that different volatility figures may be more easily compared. HV is backward-looking since it is calculated from known price data. It could be high if the stock had relatively large daily price movements over the previous 30 trading ses…

Why the Lookback Period Matters

There is not a single, universal figure for historical volatility. A trader could look at periods of 10 days, 20 days, 30 days, 60 days, or even longer. The result can be considerably affected by changing the lookback period since price shocks that have occurred recently will have a much greater impact on a shorter measurement period. Imagine a share that drops by 15 per cent following an unexpected announcement. A short-term HV calculation might respond strongly to this move, whereas a calculat…

Implied Volatility vs Historical Volatility

The simplest way to remember the difference is this: HV looks backward. IV looks at what is being priced into options. The two measures are related but not interchangeable; historical volatility can be used to give an indication of how aggressively a stock has moved, whereas implied volatility shows the amount of volatility that is contained in current option prices. Cboe points out that implied volatility is forward-looking and is based on option prices, while the realised measures rely on hist…

Why Can IV Be Higher or Lower Than HV?

Implied volatility differs from historical volatility for a number of reasons, the most obvious of which is that the options market may be expecting an event which has not yet had an effect on the stock's historical data. Earnings announcements are a typical example of this. A stock might remain almost unchanged for several months, resulting in a moderate level of historical volatility. When the earnings are due, the prices of the options may show the uncertainty surrounding the forthcoming repo…

What Does a High IV-to-HV Difference Tell Traders?

The difference between IV and HV can be useful since it shows that the volatility reflected in the options is considerably different from the volatility that the stock has recently undergone. A stock with a 25% HV but a 45% IV should be noted. It is possible that earnings are due. There could be a legal or regulatory event pending. Alternatively, traders might be paying more for options because the demand for protection has gone up. For someone who sells options, a higher implied volatility may…

How IV and HV Can Help Cash-Secured Put Traders

People who sell cash-secured puts usually keep a close eye on volatility since volatility has an impact on the premium that can be obtained from selling options. However, it can be risky to concentrate solely on stocks with high volatility since high volatility also implies a greater possibility of large price changes. A trader who is thinking of entering a cash-secured put could look at the current implied volatility together with the historical volatility, the strike price, the expiration date…

How IV and HV Can Help Covered Call Traders

Traders who use covered calls can apply the same basic approach; when you own 100 shares and sell a call against them, the level of implied volatility will affect the premium that is available for the call, and historical volatility can give some context as to how much the stock has moved in the past. Imagine that a stock has had a moderate level of historical volatility, yet its current call implied volatility has increased in the lead-up to an event. The call premium could then be higher than…

Using Volatility Surface to Analyze Options Volatility

The individual IV number by itself doesn't give the full picture since options on the same stock can have different implied volatility levels according to both the strike price and the expiration date . If you examine these factors, you can get a more complete view of how volatility is being priced. The implied volatility for stocks and ETFs across different strike prices and expirations is available through the SecurePutCalls volatility surface, and such an analysis allows traders to look at fe…

A Simple Example of IV vs HV

Imagine a hypothetical stock trading at $100 with the following figures: Historical Volatility: 25% Implied Volatility: 40% The 25% HV indicates that a 25% annualized volatility figure has been obtained from the stock's historical price movements based on the historical calculation period that was selected. The fact that the volatility index is 40% shows that the present prices of options suggest a much higher degree of volatility for the relevant option contracts; it does not indicate that the…

Common Mistakes When Comparing IV and HV

A very common error is to think that a high IV means the options are overpriced. Although IV reflects the volatility built into option prices, it is necessary to carry out a more comprehensive analysis in order to decide if an option is fairly priced. It is also a mistake to suppose that a low IV means an option is cheap, since a low IV reading can happen for valid reasons, such as a period of stable expected movement. Traders should also steer clear of comparing different time periods. A measur…

IV vs HV: What Should Options Traders Look At?

A practical IV and HV comparison can start with a simple checklist: Current IV: What volatility is currently embedded in the option price? Historical volatility: How much has the stock actually moved over the selected period? IV rank or percentile: How does current IV compare with its own historical range, when available? Expiration: Does the volatility measurement match the contract you are considering? Strike: Is the IV appropriate for that specific strike? Liquidity: Are volume, open interest…

Conclusion

The main difference between implied volatility and historical volatility is this: historical volatility reflects actual price movements in the past, whereas implied volatility represents the volatility built into current option prices. Historical volatility shows how much a stock's price has moved, while implied volatility reflects the level of future volatility that is contained in option prices. Neither of the two measures ought to be looked at by itself. For a meaningful comparison, you must…