[maxerickson]

Part of what I am saying is that there isn't much room to do that. Take some publicly traded company and examine their order book. For any company with decent volume, the bid ask spread will likely be $0.01. For companies with less volume, buyers and sellers won't waltz into the market at the same second.

Here's an exciting company with a spread of $0.01 (at the moment anyway):

http://finance.yahoo.com/q/ecn?s=WEC+Order+Book

My selection criteria was to try to find a S&P 500 component that I wouldn't expect to be among the most highly traded S&P 500 components.