people who sell stock they borrow and then buy it back when the price drops and the profit they make is the price between the price they sell it and the price they buy it back.
just go to yahoo finance and check out how many share of YRCW are under 'short interest' and that will tell you the amount of shares that the owners of are waiting to buy them back cheap.
because YRCW always bounces back, professional short sellers have been making money on YELLOW for years, just by playing the ups and downs.