Dividing the Pie

We examine the consequences of transparency in an experimental multiple-dealer market with asymmetrically informed dealers. Five professional securities traders make a market for a single security. In each trading round, one of the dealers (the "insider") is told the security's true value. We vary both pre-trade and post-trade transparency by changing the way quote and trade information is published. The insider's profits are greatest when price efficiency is lowest. Price efficiency, in turn, is reduced by pre-trade transparency and increased by posttrade transparency. Market liquidity, measured by dealers' bid-ask spreads, is improved by pre-trade transparency and reduced by post-trade transparency.