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...

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...

We develop a new likelihood-based approach to signing trades in the absence of quotes. This approach is equally efficient as the existing Markov-chain Monte Carlo methods, but more than ten times faster. It can address the occurrence of multiple trades at the same time and allows for analysis of...