US STOCKS-Wall St falls as energy lags; stocks end week up
* Apple, Facebook biggest drags on S&P 500
* Twitter jumps on reports company exploring sale
* Indexes down: Dow 0.71 pct, S&P 0.57 pct, Nasdaq 0.63 pct (Updates to close of U.S. markets)
By Lewis Krauskopf
Sept 23 (Reuters) - Wall Street retreated on Friday as lower oil prices weighed on energy shares and Facebook and Apple declined, but major indexes still posted gains for the week.
Energy was the worst-performing major S&P sector, dropping 1.3 percent. Oil prices tumbled 4 percent on signs Saudi Arabia and Iran were making little progress in achieving agreement ahead of talks by crude exporters aimed at freezing production.
Facebook shares fell 1.6 percent and were one of the biggest drags on the S&P. The Wall Street Journal reported that the social media company overestimated viewing time for video ads.
Even so, the S&P 500 recorded its best weekly performance in more than two months. Stocks were given a boost on Wednesday when the U.S. Federal Reserve decided to keep interest rates steady, leaving intact the low-rate environment that has helped fuel the bull market.
"I just think after a few strong days and a little weakness in energy that folks are taking some profit before the weekend," said Gary Bradshaw, portfolio manager with Hodges Capital Management in Dallas. "I just feel like the market is going to keep grinding higher." Continuación...