UPDATE 1-NYSE hit with another tech glitch, extends trading

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By Ellis Mnyandu and Jonathan Spicer

NEW YORK, July 2 (Reuters) - The New York Stock Exchange suffered its third technical glitch in less than a month on Thursday, this one compelling the centuries-old floor to extend the trading day by 15 minutes to finish executing orders.

Brokers on the Wall Street trading floor, run by NYSE Euronext (NYX.N)(NYX.PA), had trouble routing orders for more than an hour early in the session on Thursday. A spokesman said it was an isolated issue that did not impact the broader electronic trading system, and that regular order processing resumed by 10:50 a.m. (1450 GMT)

The Big Board briefly halted trading in some stocks, including Regis Corp (RGS.N) and Avon Products (AVP.N). Trading was extended to 4:15 p.m. (2015 GMT) from the regular 4 p.m. close, and the exchange was reviewing if trades would need to be canceled.

The problem follows two others at the NYSE -- a software glitch June 12, and an order-matching problem June 26 -- as it scrambles to retain market share and upgrade systems in order to keep pace with smaller, faster rivals such as BATS Exchange and Direct Edge.

On Wednesday, the Big Board launched a new order processor it said reduces order execution time from 105 milliseconds to 5 milliseconds. The explosion in automated trading has led many high-frequency traders to measure trading in even shorter microseconds.

NYSE Euronext and cross-town competitor Nasdaq OMX (NDAQ.O), which runs the Nasdaq Stock Market, are shedding market share to the smaller venues and non-displayed markets, and face the wider possibility that a protracted recession and regulatory changes could dampen trading volumes.

Nasdaq suffered a smattering of technical issues over the past year, including the cancellation of some late trades in Google Inc (GOOG.O) in September. (Reporting by Ellis Mnyandu and Jonathan Spicer; Editing by Jan Paschal, Gary Hill)