Drops like this aren't new to Costco, and they've usually worked out for buyers.
Counting from 2010 and using closing prices adjusted for dividends, Costco shares had fallen at least 14% from a record close nine times before this latest slide.
A year after each drop first hit 14%, the stock was higher in seven of those.
Costco 's latest sales update might give buyers a new reason to look, too.