The subject invention overcomes the limitations of known market data displays by producing a graphical market display that integrates analysis of both 1) intra-day trading activity by classes of market participant, and 2) projected market impact as a function of trade size give the present set of executable orders in an electronic securities trade execution network. In a preferred embodiment, the display is used as the graphic user interface (GUI) of an ECN. In alternate preferred embodiments, the display is offered by a market data analysis service that accesses information form one or more ECNs, exchanges, or stock market. In another alternate embodiment, the display is created by software on a user computer form liquidity information already on that user computer.