U.S. stocks ended Friday deep in the red Friday as the persistent deadlock in Greek debt talks turned investors cautious heading into the weekend. A so-called quadruple-witching day - when options and futures for stocks and stock indexes expire simultaneously, may have contributed to the late-session selloff on Friday, according to analysts. Rallies during the week, however, helped main indexes record weekly gains. The S&P 500 SPX, -0.53% finished down 11.25 points, or 0.5%, at 2,109.99, with all 10 of its main sectors closing lower. Utilities and financials lead losses. The main benchmark recorded a 0.8% gain over the week. The Dow Jones Industrial Average DJIA, -0.55% dropped 101.56 points, or 0.6%, to 18,014.28, but posted a modest 0.6% gain over the week. The Nasdaq Composite COMP, -0.31% ended down 15.95 points, or 0.3%, to 5,117.00, retreating from record highs set Thursday. The tech-heavy index clocked in a 1.3% gain over the week. Setting the stage for stocks Friday was the European Central Bank, which approved an emergency loan to Greece's banking system nearly 24 hours after eurozone finance ministers failed to strike a deal with debt-laden Greece Thursday. Eurozone leaders will hold an emergency crisis summit Monday after finance leaders again failed to reach any kind of agreement between Greece and its creditors on Thursday. Channing Smith, portfolio manager at Capital Advisors, said the market rally over the past few days has been perplexing. "Big moves on Thursday were attributed to the Fed, however, the Fed has not changed its stance. And the fact markets are at these levels despite the complete failure to find a resolution to Greece's debt problems, is baffling," Smith said. "One of the suggestions is that the market expects more liquidity from central banks because of Greek problems. Though, today's slight retreat is probably immaterial, but we will be watching if there is a selloff later in the afternoon," Smith said. Stocks to watch: ConAgra Foods, Inc. CAG, +10.86% shares surged 11% after Jana Partners LLC on Thursday disclosed a nearly 7.2% stake in the company and said it intends to use its influence to change the board of directors. FitBit Inc. FIT, +9.50% shares jumped 9.5% on its second trading day, on top of 51% gain on Thursday.
