This Element is an excerpt from Crapshoot Investing: How Tech Savvy Traders and Clueless Regulators Turned the Stock Market into a Casino (9780132599689) by Jim McTague. Available in print and digital formats.

The revolutionary change in the stock markets that you didn’t notice–and the profound impact it will have on your investments.

A revolution inexorably altered the American stock market beginning in 2007; but outside the industry, few realized it had occurred. As late as 2010, the average investor still believed that the stock market was dominated by two major exchanges: NYSE and NASDAQ. In fact, it had expanded to more than a dozen registered equity exchanges and more than 200 other stock-trading venues. . . .