SEC Said to Probe Role of Canceled Orders in Crash

The U.S. Securities and Exchange Commission is examining whether high-speed traders helped destabilize equity markets during the May 6 crash by repeatedly placing and canceling orders in an attempt to manipulate share prices, a person with direct knowledge of the inquiry said.

The strategy is among several practices being investigated by regulators, said the person, who declined to be identified because the probe isn’t public. The SEC is also looking into whether traders may have used a technique known as sub-penny quotations to artificially generate price movements, the person said. The inquiry was first reported by the Wall Street Journal.