South Korean stocks closed almost flat Tuesday as investors took to the sidelines over uncertain U.S. monetary policy ahead of its regular meeting, analysts said. The local currency edged up against the U.S. dollar.

The benchmark Korea Composite Stock Price Index (KOSPI) added 4.59 points, or 0.23 percent, to close at 1,965.74. Trading volume was light at 223.5 million shares worth 3.39 trillion won ($3.22 billion), with decliners outnumbering gainers 434 to 366.

"Investors were directionless as they await the Fed's next move with the stimulus tapering. Although the plan to scale back the bond purchases is a well-known fact, it still haunts the market because no one can be sure what it's going to be like," said Park Sung-hoon, an analyst at Woori Investment & Securities Co.

Foreigners turned net buyers of local stocks after five days of consecutive selling, but the amount was small at 12.5 billion won.

Institutional investors also scooped up shares worth a net 59.9 billion won, adding to foreign buying. But retail investors dumped a net 77 billion won.

Shipyards drove up the main index on a brighter outlook for the ailing sector, with Hyundai Heavy Industries, the world's top player, rising 3.27 percent to 252,500 won and Samsung Heavy Industries rising 4.64 percent to 37,200 won.

Top-listed firms lost ground amid the foreign selloff. Market behemoth Samsung Electronics shed 0.36 percent to 1,395,000 won and Hyundai Motor slid 0.44 percent to 227,000 won.

Shares of Korea Gas, the state-run gas supplier, tumbled 4.84 percent to 64,900 won after it said in a regulatory filing that it will run in the red this year, scrapping the earlier projection of a surplus, due to heavy losses from overseas businesses in Canada and East Timor.

The local currency ended at 1,051.10 won against the greenback, up 0.4 won from Monday's close, as foreigners increased bets on Seoul stocks, dealers said. (Yonhap News)