Differential Access to Price Information in Financial Markets

Recently exchanges have been directly selling market data. We analyze how this practice affects price discovery, the cost of capital, return volatility, and market liquidity. We show that selling price data increases the cost of capital and volatility, worsens market efficiency and liquidity, and discourages the production of fundamental information relative to a world in which all traders freely observe prices. Generally allowing exchanges to sell price information benefits exchanges and harms liquidity traders. Overall, our results show that allowing exchanges to sell market data, rather than requiring it to be made freely available to the public, is undesirable