> This is exactly what the SEC did with Reg NMS and transaction costs declined precipitously. Citation needed - correlation is not causation. The research on t

> This is exactly what the SEC did with Reg NMS and transaction costs declined precipitously. Citation needed - correlation is not causation. The research on this is mixed and plenty of people argue Reg NMS has increased transaction costs and reduced liquidity. It mostly acts as a subsidy to poorly run exchanges, and indeed the most efficient exchanges and the most liquid markets in some global products are now in Europe.