South Korea's main stock market surrendered ground for the second straight day Thursday as the market was jolted by disappointing manufacturing data from China and concerns that the U.S. Federal Reserve may move to hike up interest rates. The South Korean won declined against the U.S. dollar. The benchmark Korea Composite Stock Price Index (KOSPI) started on shaky ground and ended the day at 1,930.57, a 0.64 percent, or 12.36 points, loss from Wednesday's close.