Short interest is the number of shares sold short but not yet covered. A decrease in short interest often indicates a more bullish sentiment towards the stock, as it suggests that fewer traders are betting on the stock's price to fall. In the case of Allstate, the decrease in short interest, coupled with the fact that its short interest is lower than its peers' average, could suggest a more positive market sentiment towards the company, potentially leading to an increase in its stock price in the short term.