South Korean stocks ended 1.91 percent lower on Thursday as investor sentiment was frozen by concerns about the escalating Greece debt crisis and the pace of the global recovery, analysts said. The local currency fell against the U.S. dollar. The benchmark Korea Composite Stock Price Index (KOSPI) tumbled 39.9 points to 2,046.63. Trading volume was light at 231.1 million shares worth 5.76 trillion won (US$5.28 billion) with losers outpacing gainers 595 to 228.