One of last week's biggest losers was Skechers (NYSE: SKX), shedding 16% of its value after posting mixed second-quarter results and unappetizing guidance. The actual carnage was worse, as the stock had moved higher for three straight trading days ahead of Thursday afternoon's report, only to plunge 21% on Friday. This is the second quarter in a row in which Skechers stock suffered a decline of at least 20% the day after posting fresh financial results.