Option Prices as Predictors of Aggregate Stock Returns
Review of Futures Markets
The relative prices of S&P 500 index call and put options convey information regarding the future return of the S&P 500 index realized over the life of the options. When call options are relatively more expensive than put options, the index earns higherreturns. Specifically, the natural log of the ratio of the out-of-the-money call price to the equally out-of-the-money put price at differing moneyness levels and maturities is positively related to the return of the index realized over the life of the options. This predictability is robust to controls for the cost of carry, past returns, implied volatility, and upper moments of the underlying. Furthermore, the results do not appear to be driven by the sign of the log ratio. Portfolios of the underlying, formed when the log ratio of the options prices is positive (when call options are more expensive), statistically outperform portfolios similarly formed when the log ratio is negative (when put options are more expensive). A simple investment strategy of increasing the S&P 500 weight in a portfolio when the ln(c/p) signal is positive and decreasing the weight when the value of the signal is negative significantly outperforms a static portfolio allocation.
Balyeat, R. Brian and Ertuck, Bilal, "Option Prices as Predictors of Aggregate Stock Returns" (2008). Faculty Scholarship. Paper 38.