Seoul shares fell more than 2 percent on Monday to end at a 10-month closing low, as concerns about the impact of record high oil prices on a fragile economic recovery curbed investors' appetite for local stocks.
"Investors are wary because oil prices are unlikely to stabilise soon," said Hyun Jung-hwan, an analyst at SK Securities.
"The local economy is heavily influenced by oil and higher prices could weaken domestic consumption further."
Oil prices rose to a record $43.92 a barrel on Monday due to supply concerns and after the United States raised its security alert for a possible al Qaeda attack.
South Korea's Finance Minister Lee Hun-jai ordered senior ministry officials to draw up tougher measures to counter the effect of surging oil prices.
The benchmark Korea Composite Stock Price Index (KOSPI) closed 2.14 percent lower at 719.59 points, the lowest close since it ended at 715.24 on October 2, last year.
Softer-than-expected US GDP data released at the end of last week had also chilled investment appetite, analysts said.
"US GDP data confirmed growth in the US economy was slowing, which adds to the already mounting concerns about the weak domestic economy," said Seo Jeong-kwang, an analyst at LG Investment & Securities.
Futures-linked program selling hit most blue chips as foreign investors sold futures heavily due to a dim market outlook, analysts said.
But foreigners bought a net 123.6 billion worth of shares on the main exchange. Local institutions sold a net 158.3 billion won and retail investors bought a net 45.4 billion won.
Most blue chips took a backward step, with market leader Samsung Electronics Co Ltd, the world's biggest memory chip maker, falling 2.16 percent to end at 408,000 won.
Shares in SK Telecom Co, the country's top wireless carrier, shed 2.83 percent to end at 154,500 won, after disappointing second-quarter results released last week. Top local car maker Hyundai Motor Co lost 2.3 percent to end at 42,400 won, despite reporting sales in July nearly doubled. Analysts said Hyundai's outlook was murky due to surging labour costs and slowing economic growth in China.
But shares in Hana Bank rose 2.7 percent to end at 22,800 won after South Korea's fourth-largest lender reported a record quarterly profit on Friday.
Daum Communications Corp, South Korea's top Web site operator and the fifth-biggest stock on the tech-heavy Kosdaq bourse, plunged 5.18 percent to end at 31,100 won after it agreed to take over Lycos Inc for 111.2 billion won.
The Kosdaq finished down 1.82 percent at 325.18, a new lifetime closing low.
A total of 282 million shares worth 1.33 trillion won changed hands on the main stock exchange, compared with Friday's 289 million shares worth 1.39 trillion won.
Decliners led advancers by 532 to 181, with 70 titles ending flat.
The September KOSPI 200 futures index fell 2.05 points to 93.00 and the underlying KOSPI 200 spot index declined 2.08 points to 93.19.