* Trading opened at 0200 GMT on Mon, 4 hrs later than scheduled
* Traders say delay had limited impact
* Outage follows glitch in April (Updates with CME statement, adds CFTC, analyst and trader comments, stock price, CHICAGO dateline)
By Tom Polansek
CHICAGO, Aug 25 (Reuters) - CME Group Inc, the world's largest futures exchange operator, said it halted trading on its electronic platform for four hours on Monday because of a technical issue resulting from planned software reconfigurations.
CME, which owns the Chicago Board of Trade, New York Mercantile Exchange and other markets, made the reconfigurations over the weekend as part of ongoing upgrades to technology, a spokeswoman said in a statement.
The outage was the latest glitch to hit Chicago-based CME following the worst-ever electronic trading outage in its agricultural markets in April.
Yet, traders said the latest delay had a limited impact because volumes were mostly thin in the absence of major market-moving news over the weekend.
CME shares were up 1.2 percent at $75.76 in afternoon trading.
"If there was a night for it to be dead, that would have been the night," said P.J. Quaid, a corn options trader in Chicago.
The outage, which occurred during Asian trading hours, came as CME is planning to launch a London-based cocoa contract in the coming months in a direct challenge to rival Intercontinental Exchange Inc and is looking at entering the European wheat market.
The halt should not hurt the company's reputation because glitches are "part of the complexity of this business," said Diego Perfumo, an analyst at Equity Research Desk.
"If it's consistently happening, it becomes an issue," he said.
Last year, other exchange operators, including CBOE Holdings Inc and Nasdaq OMX Group Inc, suffered major outages.
The start of trading in all contracts on CME's electronic Globex platform, apart from Bursa Malaysia derivatives, was delayed because of the technical problem. Markets instead opened fours hours later at 9 p.m. CDT (0200 GMT).
CME "communicated with our customers and regulators as we worked toward a resolution of the issue and the reopening of the markets," company spokeswoman Laurie Bischel said in an email.
The U.S. Commodity Futures Trading Commission said it was in communication with CME personnel about the outage and declined further comment.
Among contracts traded on CME include the benchmarks for U.S. crude and agricultural markets such as wheat, corn and soybeans. Standard & Poor's 500 Index futures, treasuries, U.S. gold and silver futures are also traded on the system.
As a result of the latest trading halt, all day and session orders, including so-called good-through-date orders with an Aug. 24 trade date were cancelled. All open orders that have been acknowledged remained working, CME said. (Additional reporting by Colin Packham in SYDNEY, Manolo Serapio Jr. and Florence Tan in SINGAPORE and Douwe Miedema in WASHINGTON; Editing by Michael Perry, Joseph Radford and Marguerita Choy)