You are describing the volatility "smirk" that used to be a volatility "smile" pre the '87 crash. This is a deep question that no one really knows the answer to but there are lots of theories. Many think that after the crash of 87, OTM puts are more highly valued than other options.
The IV can be persistenly different from the historical volatility of the underlying.
nitro
The IV can be persistenly different from the historical volatility of the underlying.
nitro