I am not sure you understand - BATS is an ECN, not an exchange. In fact, most trading is on ECNs nowadays. An ECN is basically what you describe - typically a w

I am not sure you understand - BATS is an ECN, not an exchange. In fact, most trading is on ECNs nowadays. An ECN is basically what you describe - typically a web application (usually using a protocol called FIX) that matches buyers with sellers. Of course they charge a fee - there is a cost to running the data centers and ensuring regulatory compliance. See: http://en.wikipedia.org/wiki/Electronic_Communication_Network http://en.wikipedia.org/wiki/Electronic_Communication_Networ...