Traders on the floor of the New York Stock Exchange.

Is the stock market rigged?

The epic food fight between Brad Katsuyama of IEX and Bill O'Brien from BATS Global Markets on CNBC's "Power Lunch" on Tuesday obscured a larger message: the average investor buying, say, 100 shares of IBM through his Ameritrade account in all likelihood will never interact with a high frequency trader. That person's trade will get executed at the best bid and offer, and will pay a commission under $10—far cheaper than he or she would have paid twenty years ago.