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 propose a parsimonious agent-based model of a financial market at the intra-day time scale that is able to jointly reproduce many of the empirically validated stylised facts. These include properties related to returns (leptokurtosis, absence of linear autocorrelation, volatility clustering),...