U.S. stock exchanges must establish a uniform system for tracking all orders and trades under a rule approved Wednesday.

The Securities and Exchange Commission said the requirement is intended to make it easier for the government to investigate market disruptions, such as the "flash crash" two years ago that sent the Dow Jones industrial average plummeting nearly 600 points in five minutes.

The SEC voted to have all U.S. exchanges keep the same form of audit trails covering trading orders from start to routing to execution. At the present time, audit trails vary among exchanges. Regulators say that has made it more difficult to get their hands on current order data.

Regulators say the change will make it easier to pinpoint the causes of disruptions.