NYSE trading halts adjusted to trim disruptions

NEW YORK Jan 27 (Reuters) - The New York Stock Exchange will adjust the so-called circuit breakers that were adopted in response to the May "flash crash," an effort to trim the number of disruptive market halts caused by erroneous trades.

U.S. exchanges adopted the circuit breakers in June, and they remain securities regulators' centerpiece reaction to the rapid, unprecedented market plunge on May 6. [ID:nN25248510]

The breakers pause trading for five minutes in individual stocks when they move more than 10 percent in five minutes.

Following the adjustment by two of NYSE Euronext's (NYX.N) venues, the Big Board and NYSE Amex, the circuit breakers will only trigger when three trades take place beyond the 10-percent threshold, as opposed to the current single trade.

The company said it will make the adjustment on Friday.

NYSE Arca, an all-electronic exchange, and Nasdaq OMX Group Inc's (NDAQ.O) main Nasdaq Stock Market -- the other two exchanges that list U.S. stocks -- made this adjustment late last year.

"We're continually fine-tuning how these and other safeguards work," NYSE Euronext spokesman Ray Pellecchia said. "The goal in this particular case is to prevent a single erroneous trade from inadvertently triggering a circuit breaker."

More than a dozen erroneous trades -- in stocks ranging from Citigroup Inc (C.N) to Cisco Systems Inc (CSCO.O) -- have tripped the new circuit breakers since they were adopted, prompting the U.S. Securities and Exchange Commission to consider adjustments and alternatives.

Trades deemed erroneous are later canceled. (Reporting by Jonathan Spicer; Editing by Tim Dobbyn)