South Korean stocks closed nearly flat Monday, snapping a four-day winning streak amid increased valuation pressure and virus concerns, after the key stock index closed at an all-time high the previous session. The Korean won fell against the US dollar.

The benchmark Korea Composite Stock Price Index (Kospi) inched down 0.95 points, or 0.03 percent, to close at 3,301.89 points.

Trading volume was moderate at about 1.4 billion shares worth some 13.5 trillion won ($11.9 billion), with gainers outnumbering losers 562 to 300.

Foreigners sold a net 73 billion won and institutions offloaded a net 302 billion won, while retail investors bought 383 billion won.

After a muted start, the Kospi traded in negative terrain, falling through the 3,300-point mark.

Investors took to the sidelines to lock in profit after the stock index finished the previous session at an all-time high on hopes of a massive infrastructure package in the United States.

Spreading new coronavirus variants also weakened investors' appetite for risky assets.

"The overall Asian stock markets (including the South Korean Kospi) seem to have performed weak today over investors concerns about the rising Delta variant," Mirae Asset Securities analyst Seo Sang-young said.

Auto and tech large caps slowed in Seoul, while insurance and financial stocks advanced.

Market bellwether Samsung Electronics rose 0.38 percent to 81,900 won while No. 2 chipmaker SK hynix lost 1.95 percent to 126,000 won.

Internet portal operator Naver shed 0.49 percent to 408,000 won, while giant pharmaceutical firm Samsung Biologics retreated 0.71 percent to 843,000 won.

Top automaker Hyundai Motor lost 0.82 percent to 241,000 won, and leading chemical firm LG Chem declined 0.95 percent to 830,000 won.

The local currency closed at 1,130.3 won against the US dollar, down 2.6 won from the previous session's close.

Bond prices, which move inversely to yields, closed lower. The yield on three-year Treasurys rose 2.9 basis points to 1.470 percent, and the return on the benchmark five-year government bond added 2.9 basis points to 1.793 percent. (Yonhap)