A close look at short selling on Nasdaq

We examine the frequency of short selling in stocks listed in the Nasdaq market. Using previously unavailable transaction data, we can report several findings: (1) overall, 1 of every 42 trades involves a short sale; (2) short selling is more common among stocks with high returns than stocks with weaker performance; (3) actively traded stocks experience more short sales than stocks of limited trading volume; (4) short selling varies directly with share price volatility; (5) short selling does not appear to be systematically different on various days of the week; and (6) days of high short selling precede days of unusually low returns.