NYMEX crude ends down, volatile at options expiry

NEW YORK, May 15 (Reuters) - U.S. crude oil futures finished slightly lower on Thursday, after volatile trading associated with the June crude contract options expiration.

A slide by natural gas futures helped the steep sell-off by crude futures intraday, traders said. A power outage that shut the Intercontinental Exchange's trading platform also was cited as adding to the volatility.

On the New York Mercantile Exchange, June crude CLM8 slipped 10 cents or 0.08 percent to settle at $124.12 per barrel, having traded in a wide range of $120.75 to $126.64.

Tuesday's $126.98 high was a record peak.

"The inability to hold the early high helped cause the sell-off, but this market has shown resilience time and again and every pullback has resulted in a rally," said Eric Wittenauer, analyst at Wachovia Securities.

NYMEX natural gas futures tumbled sharply after an unexpectedly large weekly inventory build was reported.

June natural gas NGM8 slid 19.9 cents, or 1.72 percent, to settle at $11.399 per million British thermal units.

The U.S. Energy Information Administration on Thursday said that natural gas storage rose 93 billion cubic feet last week, above expectations for an 87 bcf build.

The dollar strengthening versus the euro also was seen as a factor helping pressure crude futures.