A number of recent theoretical studies have explored trading in fragmented markets, e.g. Biais etal. (2000), a phenomenon increasingly witnessed in modern markets. The key assumptiongenerating the results is that there is at least one liquidity demander exploiting access to allmarkets by...

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...