Speeding up the exchange does not necessarily improve liquidity. The price quotes of high-frequency market makers are more likely to meet speculative high-frequency "bandits", thus less likely to meet liquidity traders. The bid-ask spread is raised in response. The recursive dynamic model...

The first paper is co-authored with Sylvain Delalay. We examine the impact of competition between ETFs on measures of market quality of the funds. The surge in new ETF creation has for consequence that groups of competing ETFs are increasingly crowded, and investors can choose from a multitude...