Using euro conversion as the trigger, we examine what drives volume and spread changes when stock exchanges compete. Results show average trading costs on European exchanges decrease almost 9%, and turnover increases over 30%. Trading costs decline or remain unchanged on all exchanges, but volume deteriorates in some markets and improves in others. Frankfurt, Paris, London, and Milan are winners, while Madrid and Brussels lose volume. We examine the role of the spread-volume relation, firm characteristics, exchange trading rules, and country-level factors in determining these outcomes. Results suggest that euro conversion prompted competition by increasing transparency in market prices.

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.