This paper links the recent fragmentation in equity trading to high frequency traders (HFTs). It shows how the success of a new market, Chi-X, critically depended on the participation of a large HFT who acts as a modern market-maker. The HFT, in turn, benefits from low fees in the entrant...

Speeding up the exchange does not necessarily improve liquidity. On the one hand, more speed enables a high-frequency market maker (HFM) to update his quotes faster on incoming news. This reduces his payoff risk and thus lowers the competitive bid-ask spread. On the other hand, HFM price quotes...

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...

Algorithmic trading has sharply increased over the past decade. Equity market liquidity has improved as well. Are the two trends related? For a recent five-year panel of New York Stock Exchange (NYSE) stocks, we use a normalized measure of electronic message traffic (order submissions,...