Most research on short selling treats short sellers as relatively homogenous. We show that there are at least two distinct groups of short sellers, which we call Short Traders and Short Investors. Short Traders are more risk-averse and have shorter horizons. They trade in easy-to-borrow stocks over just a few days and are informed about events such as analyst downgrades. Short Investors short and hold expensive-to-borrow positions over long horizons (months), and are willing to take on substantial risk, measured as both price and lending fee volatility. Short Investors are informed about firm fundamentals. While both types of short sellers are informed and their behavior predicts negative returns, we show that they are not informed about the same things and predict returns over different time horizons.