Wall Street Journal Article detailing how NYSE has advantages over electronic markets in regard to stock pricing. "Trade Through" rule requires that investor is given best price even if the order has to be filled through a bigger market (such as NYSE)

"The SEC Tuesday plans to consider proposals that could alter how stocks are quoted, what fees markets can charge for access to quotes and how investors trade securities. The agency is trying mitigate disparities in the way it regulates different markets. Pressure for changes is growing and some lawmakers say Congress could legislate if the SEC's changes don't go far enough."