1) Markets fall faster than they rise — and options traders know this. Otherwise, arbitraging this difference would be a meal for a lifetime.

2) Market participants perhaps anticipate that the realized volatility during a bear market is greater than a bull market. However, the problem with this analysis is one might expect to see an upward sloping volatility yield curve in out-of-the-money puts (during bull markets), and yet that does not usually occur based on my tests. Conversely, right now have a downward sloping yield curve in out of the money calls — which confirms the hypothesis that market participants anticipate slower price rises in the future. [Note to quants: I am not confusing delta, gamma and vega. I’m using options to predict terminal price at expiration.]

3) For most humans, fear of loss is a stronger emotion/motivator than the pleasure of gain (greed). This is well documented in the psychology and behavioral finance literature. Hence, ceterus paribus, capital market participants (who have a net long position) will, as a group, pull their rip cord faster — to flee from risk — than they will embrace the possibility of profit.