"In fact, many contrarian investors use short interest as a tool to determine the direction of the market. The rationale is that if everyone is selling, then the stock is already at its low and can only move up. Thus, contrarians feel that a high short-interest ratio (which we will discuss below) is bullish - because eventually there will be significant upward pressure on the stock's price as short sellers cover their short positions (i.e. buy back the stocks they borrowed to return to the lender). (Learn more in Can Perpetual Contrarians Profit As Traders?)"
Maybe some investors will use short float to predict price movement, LOL