Nasdaq adds 12 stocks to list of canceled trades

NEW YORK (Reuters) - Nasdaq OMX Group Inc (NDAQ.O) said on Sunday it has added 12 stocks to the list of trades it was canceling following Thursday's sudden market plunge.

All but one of the stocks Nasdaq added are listed on an exchange operated by rival NYSE Euronext (NYX.N).

The Dow Jones Industrial Average suffered a thus far unexplained intraday plunge of nearly 1,000 points on Thursday afternoon before paring much of that decline, prompting exchanges to cancel trades that occurred on hundreds of stocks during the market's swoon.

Of the 12 stocks Nasdaq added on Sunday, 11 are listed either on the New York Stock Exchange or its sister exchange Arca, which like the Nasdaq Stock Market is all electronic.

NYSE and Nasdaq issued a joint statement on Sunday saying they were "committed to working closely with each other" and the U.S. Securities and Exchange Commission to find out what caused Thursday's plunge.

The statement comes after a sniping match on Friday between the heads of the two exchange operators that included Nasdaq OMX Chief Executive Robert Greifeld faulting an NYSE mechanism that slows floor trading when prices move too sharply.

The additions include the index-based IQ Hedge Macro Strategy Tracker ETF (MCRO.P) and WisdomTree LargeCap Growth Fund ROI.P, which are both listed on Arca, and the PowerShares S&P SmallCap Utilities Portfolio XLUS.O which lists on Nasdaq.

Nasdaq is canceling all trades made between 2:40 p.m. EDT and 3 p.m. EDT on Thursday that deviated more or less than 60 percent away from the consolidated last print in that security at 2:40 p.m. or just before. Nasdaq said last week its decision cannot be appealed.

An updated list of stocks affected by the cancellations released by Nasdaq on Sunday included 236 stocks. To view the list, please see: here

(Reporting by Phil Wahba, editing by Maureen Bavdek)