Implied versus realized volatility is a comparison between priced uncertainty and observed market movement. Implied volatility comes from option prices and reflects how much future variability the options market is pricing into a contract. It is forward-looking in the sense that it is tied to expectations, hedging demand, and uncertainty about what may happen before the option expires.
Realized volatility comes from the underlying asset’s past returns. It measures how variable price action actually was over a chosen historical window. That makes it backward-looking, but not trivial. It is a record of how much movement the market already produced, not a quote on what traders fear or expect next.
The key point is that both numbers refer to volatility, but they do not describe it through the same channel. One is inferred from derivatives pricing before outcomes are known. The other is calculated from price behavior after outcomes have already occurred. Treating them as interchangeable hides the difference between how uncertainty is priced and how volatility is later realized.
What Each Measure Represents
Implied volatility represents the market’s current price for uncertainty. It is embedded in option premiums, so it reflects not only directional expectations, but also the value of protection, the distribution of possible outcomes, and the willingness of market participants to pay for insurance against those outcomes. It is therefore a market price of expected variability, not a direct reading of future returns.
Realized volatility represents the dispersion that actually showed up in the underlying market over a completed period. It tells you how unstable the path of returns already was, using historical data rather than live option pricing. That makes it an observed outcome measure rather than a live market estimate.
This is why the comparison is not simply future versus past. The deeper distinction is priced uncertainty versus observed variation. Time orientation matters, but the larger difference is that each measure answers a different question about the same broad concept.
How the Numbers Are Built
Implied volatility is backed out of option prices. Its value depends on an active options market, quoted premiums, strike selection, maturity, and the pricing conditions embedded in those contracts. If option prices change because demand for hedging rises or event risk becomes more important, implied volatility can move even before the underlying asset makes a large move.
Realized volatility is built from the return series of the underlying asset itself. Its value depends on the historical window being measured and on how much dispersion actually occurred inside that sample. Change the lookback period, and the realized volatility reading can change with it because the calculation is tied to the path already taken by the market.
That construction difference matters because the two measures are not rival estimates generated from the same raw input. They come from different sources, respond to different pressures, and compress uncertainty in different ways. A gap between them is not automatically an error. It often just reflects the fact that the market priced uncertainty one way before the path of returns unfolded another way afterward.
Why Implied and Realized Volatility Diverge
Divergence is normal because implied volatility is formed before outcomes are known, while realized volatility is assembled after those outcomes have already happened. One describes a distribution of possibilities that is still open. The other records the single path that the market ultimately took. Those two things will often differ even when markets are functioning normally.
The contrast becomes especially visible around event risk. Before earnings, policy decisions, inflation releases, or other scheduled catalysts, option prices may rise because traders know uncertainty is high but do not know which path prices will follow. Once the event passes, realized volatility records only the move that actually occurred. If the market had priced a wider range of possibilities than what was ultimately realized, implied volatility will have stood above realized volatility. If the actual move is larger than expected, realized volatility can end up exceeding what had been priced in advance.
Persistent differences can also reflect more than forecasting error. Implied volatility can include compensation for bearing uncertainty and for supplying protection when hedging demand is strong. Realized volatility contains no such premium because it is not a price for risk transfer. It is simply an observation of what happened. That is why the spread between the two can remain meaningful even without any dramatic market dislocation.
How to Interpret the Comparison
The comparison is most useful when it keeps the question narrow. Implied volatility tells you how uncertainty is being priced now. Realized volatility tells you how much variability has already been expressed in returns. The relationship between them helps clarify whether the options market is pricing a wider, narrower, or differently shaped uncertainty set than the one the market later delivers.
What the comparison does not do on its own is fully explain regime conditions, prove mispricing, or decode every volatility signal in the market. A gap between the two may reflect event anticipation, hedging demand, risk premium, or a simple mismatch between expected and actual outcomes. The comparison helps you separate expectation from outcome, but it does not turn that spread into a complete framework by itself.
Used properly, implied versus realized volatility is a boundary-setting distinction. It prevents a common mistake: assuming that every volatility number means the same thing. They refer to the same domain, but one is a market price for uncertainty and the other is a historical measure of movement already observed.
FAQ
Is implied volatility a forecast of what will happen?
Not in a pure sense. It is a price-based estimate that reflects expectations, uncertainty, and demand for protection. That makes it forward-looking, but it also means it can include risk premium and hedging pressure rather than serving as a clean forecast of future realized movement.
Can realized volatility end up higher than implied volatility?
Yes. That happens when the market moves more violently than option prices had embedded in advance. It often shows up when outcomes are more disruptive than expected or when a catalyst produces a larger move than the options market priced beforehand.
Why is implied volatility often above realized volatility?
Because option buyers are often willing to pay for protection against uncertainty, especially around stress or event risk. That can keep priced volatility above subsequently observed volatility even when the market is functioning normally.
Which measure matters more for options traders?
Both matter, but for different reasons. Implied volatility matters for how options are priced now, while realized volatility matters for judging how much movement actually occurred and for comparing priced uncertainty with the market’s eventual path.