US STOCKS-S&P 500 slides below closely watched threshold
* U.S. crude rises more than 3 pct
* Valeant drops after delaying release of results
* Indexes end down: Dow 0.74 pct, S&P 0.81 pct, Nasdaq 0.71 pct (Updates to close)
By Noel Randewich
Feb 29 (Reuters) - Wall Street ended lower on Monday, falling out of lockstep with oil prices as energy and healthcare shares lost ground.
U.S. indexes gave up early gains despite a 3 percent rally in U.S. oil prices. Stocks and oil have been strongly correlated in recent months as crude prices tanked to decade lows, and their movements in opposite directions during the session was notable to investors.
Following gains last week, technical trading dominated the action as the S&P 500 fell below its 50-day moving average, a sign seen as bad for sentiment. The index broke above the average on Thursday for the first time this year.
"If stocks rally up to a declining 50-day average, people will sell against that," said Michael Matousek, head trader at U.S. Global Investors Inc in San Antonio. "From a psychological standpoint, you have that overhead resistance at that level."
Nine of the 10 major S&P sectors fell, led by a 1.58 percent decline in the healthcare sector, with Amgen Inc down 3.60 percent. Continuación...