Seoul, Nov 9 : South Korea's main stock index recorded its biggest-ever weekly sell-off by foreign investors in the first week of November as profit-taking and concerns over an artificial intelligence (AI) stock bubble spurred a market retreat, the Korea Exchange said on Sunday.

From Monday to Friday, foreign investors dumped a net 7.26 trillion won (US$4.98 billion) worth of shares on the benchmark Korea Composite Stock Price Index (KOSPI), the bourse operator said, reports Yonhap news agency.

The amount marked the largest weekly sell-off by foreign investors in KOSPI history, surpassing the previous record of 7.05 trillion won in the second week of August 2021.

The KOSPI experienced sharp volatility last week, climbing to a record high above 4,200 on Monday before plunging nearly 3 percent Wednesday. After a brief rebound Thursday, the index shed 1.81 percent Friday, closing below the 4,000 mark.

The benchmark had been the fastest-rising major stock index among Group of 20 nations as of Oct. 27, buoyed by strong foreign buying of semiconductors and other blue chip stocks, according to data compiled by Yonhap Infomax, the financial arm of Yonhap News Agency.

But the rally fueled profit-taking among foreign investors, especially after Wall Street slumped last week amid revived fears of an AI bubble, analysts said.

Samsung Electronics Co., the world's biggest memory chip maker, and its rival SK hynix Inc. accounted for more than 70 percent of foreign sell-offs last week.

Foreigners unloaded 1.5 trillion won worth of Samsung shares and 3.7 trillion won in SK shares, data showed.

"With the U.S. federal government shutdown marking the longest in history, uncertainty over its economic impact has deepened," said Chung Hae-chang, an analyst at Daishin Securities. "Given the lack of upward momentum and investor optimism, the market is likely to remain in a consolidation phase for the time being."

Lee Sung-hoon, an analyst at Kiwoom Securities, noted that the recent weakness of the Korean won will also sap foreign investors' appetite, saying that foreign inflows are unlikely to rebound soon.

The local currency fell below the psychologically crucial 1,450 won threshold Friday, dipping to its lowest level in nearly seven months.

/IANS