Volatility Mean Reversion – the tendency of implied volatility to inherently revert to it’s long term mean value, often quite quickly after an implied volatility spike. Meaning that when it is “high” (as defined by IV Rank) it tends to come down back to its long term average over time. This is implying that selling volatility via spread strategies with “high” priced options (that is those with an IV Rank of greater than 50%) tends to be successful in the long term. This is because implied volatility is generally overstated versus actual realized volatility.