Before the internet, very few individuals traded foreign exchange as they could not get access to a level of pricing that would allow them a reasonable chance to profit after transaction costs. Shortly after the internet became mainstream however several firms built online trading platforms which gave the individual trader a much higher level access to the market. The internet introduced two main features into the equation which were not present before.

For now it is simply important to understand that what these firms did was take all the traders who were not big enough by themselves to get access to good pricing and routed their order flow through one entity that was. This allowed these firms access to much tighter pricing than would otherwise have been possible which was then passed along plus a little for the brokers to the end client. Another key thing that it is important to understand here is that the larger a firm gets in terms of trading volume, the greater access that firm has to tighter prices and liquidity and the more likely that firm is to be able to pass on better pricing and execution to their clients.