Seoul stocks fell 1.72 percent to a new six-month closing low on Thursday, as bank shares such as Woori Financial Group slid following the trading debut of Bank of China on the Hong Kong bourse.
Analysts said strong demand for shares in China's second-largest lender, which raised a massive $9.7 billion in its initial public offering last week, had hurt the sector.
"Because of Bank of China, we saw much money go to China. But looking at valuations, Korea's benchmark bank Kookmin Bank compared with BoC is cheaper, so foreign investors will come back," said Park Kum-yung, a fund manager at Mirae Asset Co.
The benchmark Korea Composite Stock Price Index (KOSPI) settled at 1,295.09, surpassing the previous 2006 closing low of 1,295.76 set a week ago. It was the sixth time this year the index dropped below 1,300.
Among the decliners, top lender Kookmin Bank shed 3.1 percent to 75,100 won, while Woori Financial Group fell 4.1 percent to 18,700 won.
Market heavyweight Samsung Electronics Co Ltd lost 0.98 percent to 606,000 won after paring gains. The world's top maker of memory chips said its semiconductor business was recovering quickly.
Hyundai Heavy Industries Co, the world's largest shipbuilder, eased 0.31 percent to 96,500 won, and Daewoo Shipbuilding and Marine Engineering Co the world's No 2 shipbuilder, was unchanged at 26,000 won. Third ranked Samsung Heavy Industries Co ended steady at 20,050 won.
Bucking the weaker market trend were defensive sectors such as telecom shares. SK Telecom put on 2.0 percent to 230,000 won and KT Corp added 1.61 percent to 41,000 won.
Trade volume reached 236.2 million shares worth 3.3 trillion won compared to Tuesday's 217.6 million shares worth 3.2 trillion won. Decliners outpaced gainers by 629 to 132 with 51 titles ending flat.
Foreign investors were net buyers for a third straight session, buying a net of 58.6 billion won in shares on the main bourse. But retail and institutional investors were both net sellers, with net sales of 42.9 billion won and 81.1 billion won respectively.
The June KOSPI 200 futures index slid 1.7 percent to 167.95 and the underlying KOSPI 200 spot index ended down 1.74 percent at 168.03. South Korea's junior and tech heavy Kosdaq market shed 2.81 percent to finish at 612.80.