IV Crush
IV crush is a sharp decline in implied volatility, commonly associated with the removal of uncertainty after a significant scheduled event.
Why it matters to you
Before earnings, options may price substantial uncertainty. Once the company reports, much of that event uncertainty disappears. IV can fall rapidly. A trader who bought expensive options before the announcement may therefore lose value from falling IV even if the underlying moves in the expected direction. Getting the direction right does not guarantee getting the option trade right.