South Korean stocks fell slightly Thursday to end their three-day winning streak as major shares ended in mixed territory. The local currency fell against the US dollar for the first time in six sessions. The benchmark Korea Composite Stock Price Index lost 1.66 points, or 0.07 percent, to close at 2,480.63. The main index had been rising since Monday. Trade volume was moderate at 440.4 million shares worth 8.1 trillion won ($5.8 billion), with decliners beating gainers 477 to 392. Foreigners du