25D Risk Reversal measures the implied volatility of a 25 delta call – the implied volatility of a 25 delta put, both with 30 days to expiration.

Why does 25D Risk Reversal matter?

This reflects the demand of put options vs call options. 

How to use 25D Risk Reversal

Sharp changes in this ratio indicate a change in investor demand. When the ratio shifts towards 0 it indicates call demand, and away from zero indicates traders are placing a higher price on put options.