The Perrigo Principle in Effect

The Pareto principle (also widely-known as the 80–20 rule) states that, in general, roughly 80% of the effects come from 20% of the causes in most events. 

Applied to the huge down move in PRGO today, on the back of news that CEO Papa left to head rival firm VRX, we may very well apply the "Perrigo Principle." Specifically, on a slow market day, while many are attributing the sharp sell-off the CEO leaving, it may very well have been an excuse rather than a catalyst for the move. 

On the monthly chart, below, note the very steep multi-year rally PRGO enjoyed. Once that steep trend was broken, pretty much any excuse would do to sell, for once very steep trends are breached (especially on this timeframe) it is typically as good a sign as any to respect the lost momentum and acknowledge that the market may very well be in the process of cleaning out the excesses of the run-up. 

Put another way, let's not sensationalize the CEO here--The chart may very well have been ripe to do this anyway.