We use daily short-selling data to examine whether short selling around seasoned equity offerings (SEOs) reflects informed or manipulative trading. Around SEO announcements, we find no evidence of informed short selling. Around issue dates, higher levels of pre-issue short selling are significantly related to larger issue discounts for non-shelf-registered offerings. This evidence is consistent with manipulative trading. We show that SEC Rule 105 constrains some but not all manipulative trading. Our results reverse previous research that uses monthly short-interest data, because daily data allow more powerful tests. Our evidence helps explain the increased popularity of shelf registrations. Although short selling usually enhances price efficiency, we document a situation where short selling reduces price efficiency.

Prior literature examines the effect of either informed or arbitrage short selling on equity markets. We test the relative importance of informed and uninformed short selling around convertible bond issues and earnings announcements for the same firms over the same time period. Convertible arbitrage short selling is associated with temporary price pressure, consistent with downward sloping demand curves. Earnings announcement short selling is consistent with informed traders who anticipate future returns. Firm-specific characteristics related to the cost of short selling similarly affect both informed and arbitrage short selling. Deal-specific characteristics capturing hedging demand also strongly determine convertible arbitrage short selling.

We examine whether short sellers identify firms that have significant changes in default likelihoods and credit rating downgrades. In the month before a rating downgrade, equity short interest is 40% higher than one year prior. Short sellers predict changes in default probabilities that lead to downgrades by focusing on firms with inaccurate or biased ratings. This strategy is profitable for short sellers primarily since downgrades are associated with significantly negative equity returns. Short sellers also facilitate price discovery by reducing abnormal stock returns following downgrades and by leading bond yield spreads.

This article shows how to evaluate the performance of managed portfolios using stochastic discount factors (SDFs) from continuous-time term structure models. These models imply empirical factors that include time averages of the underlying state variables. The approach addresses a performance measurement bias, described by Goetzmann, Ingersoll, and Ivkovic (2000) and Ferson and Khang (2002), arising because fund managers may trade within the return measurement interval or hold positions in replicable options. The empirical factors contribute explanatory power in factor model regressions and reduce model pricing errors. We illustrate the approach on US government bond funds during 1986–2000.