Advances in telecommunication technology in the nineteenth century encouraged greater centralization of liquidity on single, dominant exchanges in most major industrialized countries. Electronic trading, in contrast, has precipitated increased market fragmentation, creating a host of new regulatory dilemmas. In an attempt to understand this phenomenon, this chapter proposes a two-stage process of market structural development in response to electronic trading. This process is then examined in equities and foreign exchange markets. Despite significant differences between these two asset classes, they have exhibited a remarkably similar pattern of disintermediation followed by reintermediation. This analysis is followed by a survey of recent regulatory approaches to mitigate the negative externalities associated with electronic trading. It concludes with a brief discussion on the future of market fragmentation and centralization in global capital markets.
