Seoul stocks trimmed earlier gains late in the morning today as institutions increased their selling ahead of quarterly earnings releases, analysts said.
The Korea Composite Stock Price Index (KOSPI) added 1.09 points, or 0.05 percent, to trade at 2,217.74 as of 11:20 a.m.
Institutions sold a net 73 billion won (US$64 million) worth of stocks. Foreigners and individuals bought a combined 67 billion won worth of stocks.
Analysts said the main index will move in a tight range as major firms such as Hyundai Motor are set to report their first-quarter earnings results from Wednesday.
Hyundai Motor, Kia Motors, Posco and LG Chem are scheduled to release their quarterly earnings results this week.
Airline stocks were lead decliners due to rising oil prices and the won's weakness against the dollar.