Improved information technology and higher volume should drive orders to be concentrated in one market, lowering the costs of transactions. However, the opposite occurred during the bull market of the 1920s when rapid technological change spawned a flood of new issues. This article employs newly recovered data for 1900-33 on the volume and seat prices of regional exchanges to examine how these rivals successfully competed with the NYSE, leading to its relative decline at the zenith of the market. The history of US exchanges reveals that the tendency towards concentration of trading is periodically reversed when new industries, whose technologies are risky and unfamiliar, are more easily accommodated by existing or new rivals to the dominant exchange.
