Why Short-Dated Implied Volatility Is Not a Simple Gainer Predictor

Summary

The document examines whether stocks with the highest implied volatility in options expiring the next day will also have the largest moves on the following day. It cautions that implied volatility is an estimate of a volatility parameter, not a direct ranking of future stock returns or gainers and losers. The estimate can vary substantially between trades, so a high reading alone may be an unreliable forecast of realized movement.

One answer suggests comparing implied volatility with historical volatility and considering time to expiration when interpreting the options market’s expectations. A large gap may reflect an expectation of a sizable move in either direction, but it does not establish whether the stock will rise or fall. The discussion offers no empirical test, forecasting procedure, or evidence that this comparison identifies the next period’s biggest movers. It is a conceptual warning: implied volatility can contain information, but predicting cross-sectional price moves requires more than sorting stocks by a single short-dated IV value.

Key ideas

• Implied volatility estimates expected volatility and does not indicate the direction of a stock’s next move.
• Implied volatility can fluctuate substantially between trades and may not reliably estimate realized volatility.
• Comparing implied volatility with historical volatility and time to expiration may add context to the market’s expectations.
• A high implied volatility reading alone does not establish which stocks will become the largest gainers or losers.

Tags

# Can I use implied volatility of stocks to predict the next days or weeks top 10 gainers and losers?


# Can I use implied volatility of stocks to predict the next days or weeks top 10 gainers and losers?












Is it true if I said that the stocks with the highest implied volatility for its options with just one day to expiration today will inadvertently be the stocks with the largest price movements on the next day? What is wrong with that thinking? Please explain.

## Answer by Itai (score 1, accepted)

https://quant.stackexchange.com/a/40673

That said, option market makers are very well informed traders that take large risk and so some of their information is reflected in the IV inputs, for example, if the stocks 30 day HV is 15% and 20 days to expiration they input 45% as expected future Volatility (IV) then they expect a big move (up or down) in the underline. So to answer your question , one can not only rely on the IV value and DTE but rather learn for the relationship between known HV and expected volatility (IV) to even begin starting to model a prediction. IMHO.

## Answer by userid is i (score 1)

https://quant.stackexchange.com/a/40667

It would be a reasonable statement with "highest volatility." But implied volatility is a particular estimate of the volatility parameter which jumps around greatly from trade to trade and is not a good estimator of volatility.

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.