According to the American Stock Exchange, short interest in the XLY represented 45% of total shares outstanding as of mid-April, and the IYC had 10.2% of its shares held short. Meanwhile, short interest for individual U.S. stocks averages around 2%. A short sale is a market transaction in which an investor sells borrowed securities in anticipation of a price decline. Selling short is the opposite of going long. That is, short-sellers make money if the stock goes down in price. "There is a link between consumer confidence and the underperformance of consumer discretionary ETFs," says Kevin Ireland, vice president at the American Stock Exchange. Ireland adds that even with high levels of short interest in the XLY and IYC, however, the likelihood of a short squeeze is not too great since "most of the squeezing will be done in the underlying stocks, not the ETFs."