This article analyzes intraday patterns for U.K. and U.S. trading of British cross-listed stocks. For each market, the intraday patterns for these stocks closely resemble those of otherwise similar, non-cross-listed stocks. There is a 2-hour period each day when cross-listed stocks are traded both in New York and in London. This overlap is characterized by concentrated trading as private information, originating in New York, gets incorporated into prices in both markets. Cross-border competition for orderflow tends to reduce already declining spreads in London. By contrast, New York specialists maintain high spreads during the overlap. Overall, the evidence indicates that order flow for cross-listed securities is segmented.

We argue that competition between dealers in a classic dealer market is intertemporal: A trader identifies a particular dealer and negotiates a final price with only the intertemporal threat to switch dealers imposing pricing discipline on the dealer. In this kind of market structure, we show that dealers will offer greater price improvement to more regular customers, and, in turn, these customers optimally choose to submit larger orders. Hence, price improvement and trade size should be negatively correlated in a dealer market. We confirm our model's predictions using unique data from the London Stock Exchange during 1991.

We show that when a continuous dark pool is added to a limit order book that opens illiquid, book and consolidated fill rates and volume increase, but spread widens, depth declines, and welfare deteriorates. The adverse effects on market quality and welfare are mitigated when book-liquidity builds but so are the positive effects on trading activity. All effects are stronger when traders’ valuations are less dispersed, access to the dark pool is greater, horizon is longer, and relative tick size larger.

We use unique data from the London Stock Exchange to test whether interdealer trade facilitates inventory risk sharing among dealers. We develop a methodology that focuses on periods of “extreme” inventories—inventory cycles. We further distinguish between inventory cycles that are unanticipated and those that are anticipated because of “worked” orders. The pattern of interdealer trade during inventory cycles matches theoretical predictions for the direction of trade and the inventories of trade counterparts. We also show that London dealers receive higher trading revenues for taking larger positions.

We examine the effects of the Securities and Exchange Commission (SEC)‐mandated temporary suspension of short‐sale price tests for a set of Pilot securities. While short‐selling activity increases both for NYSE‐ and Nasdaq‐listed Pilot stocks, returns and volatility at the daily level are unaffected. NYSE‐listed Pilot stocks experience more symmetric trading patterns and a slight increase in spreads and intraday volatility after the suspension while there is a smaller effect on market quality for Nasdaq‐listed Pilot stocks. The results suggest that the effect of the price tests on market quality can largely be attributed to distortions in order flow created by the price tests themselves.

Studying a comprehensive sample of stocks from the U.S. OTC market, we show that this market is a large and diverse trading environment with a rich set of regulatory and disclosure regimes, comprising venue rules and state laws beyond SEC regulation. We exploit this institutional richness to show that OTC firms subject to stricter regulatory regimes and disclosure requirements have higher market quality (higher liquidity and lower crash risk). Our analysis points to an important trade-off in regulating the OTC market and protecting investors: lowering regulatory requirements reduces the compliance burden for smaller firms, but it also reduces market quality. Received July 26, 2013; editorial decision July 8, 2017 by Editor Itay Goldstein.