Following Thursday’s wild ride for the markets, and rumours of trading errors as one of the causes, regulators are looking for answers.

The U.S. Securities and Exchange Commission and the U.S. Commodity Futures Trading Commission released a statement indicating that they are, “working closely with the other financial regulators, as well as the exchanges, to review the unusual trading activity that took place… We are also working with the exchanges to take appropriate steps to protect investors pursuant to market rules. We will make public the findings of our review along with recommendations for appropriate action.”

Chicago-based CME Group also issued a statement regarding rumors that erroneous or irregular trades by Citigroup Global Markets Inc. in CME Group stock index futures markets was the source of the mistake. “While our policy is not to comment on individual participation in our markets, in light of volatile market conditions, CME Group confirmed that activity by Citigroup Global Markets Inc. in CME Group stock index futures markets does not appear to be irregular or unusual in light of market activity today,” it said.

The Nasdaq Stock Market said it had no technology or system issues associated with the unusual trading, and that there is no indication that a Nasdaq market participant experienced a technological failure.

However, NASDAQ also said that it “will cancel all trades executed between 14:40 and 15:00 greater than or less than 60% away from the consolidated last print in that security at 14:40 or immediately prior.” It added that this decision cannot be appealed, and that it will be canceling trades on participants’ behalf.

The stocks affected and the break points are posted here: http://media.globenewswire.com/cache/6948/file/8211.htm