South Korean shares dropped more than 1.5 percent Monday after hitting an all-time high the previous session as investors attempted to cash in gains. The Korean won fell against the US dollar.

The benchmark Korea Composite Stock Price Index (KOSPI) fell 42.11 points, or 1.6 percent, to close at 2,591.34.

Trading volume was high at about 1.28 billion shares worth some 20.4 trillion won ($18.4 billion), with losers outnumbering gainers 511 to 331.

Foreigners sold a net 2.4 trillion won, while retail investors picked up a net 2.2 trillion won. Institutions purchased a net 202 billion won.

The KOSPI got off to a muted start, before turning lower in the morning on foreign investors' profit-taking drive.

"Foreigners bought a net 7 trillion won of local stocks this month, and with the KOSPI up 16 percent over the same period, investors are locking in gains," said Seo Jung-hoon, an analyst at Samsung Securities.

Most large caps in Seoul ended lower.

Market bellwether Samsung Electronics lost 2.2 percent to 66,700 won, and No. 2 chipmaker SK hynix shed 1.32 percent to 97,500 won.

Internet portal giant Naver declined 2.46 percent to 277,500 won, with its rival Kakao dipping 1.34 percent to 368,000 won.

Leading chemical maker LG Chem fell 1.23 percent to 800,000 won, and rechargeable battery maker Samsung SDI dropped 3.27 percent to 533,000 won.

Pharmaceutical giant Samsung Biologics fell 1.63 percent to 786,000 won, while Celltrion climbed 1.8 percent to 340,000 won.

Hyundai Motor, the country's largest automaker, inched up 0.28 percent to 181,500 won.

The local currency closed at 1,106.5 won per dollar, down 3.3 won from the previous session's close, when it reached a 29-month high. (Yonhap)