South Korean stocks extended losses to the second straight session Wednesday as investors offloaded tech shares amid concerns about regulations against online platform giants.

The benchmark Korea Composite Stock Price Index (KOSPI) shed 24.43 points, or 0.77 percent, to close at 3,162.99 points.

Trading volume was high at about 839.72 million shares worth some 16.89 trillion won ($14.5 billion), with losers outnumbering gainers 560 to 307.

Foreigners sold a net 283 billion won worth of local shares, and institutions offloaded a net 118 billion won. Retail investors picked up a net 423 billion won.

The main index started off on a downbeat note amid investor concerns over the pace of the US economic recovery from the pandemic-induced slump after a disappointing US jobs report released Friday (US time).

The KOSPI traded bearish throughout the session as investors dumped online platform stocks amid growing concerns about regulations against their market dominance.

A day earlier, ruling Democratic Party lawmakers voiced concerns over the market dominance of tech giant Kakao and its rapid business expansion, from banking to ride-hailing, in recent years.

Rep. Yun Ho-jung, the floor leader of the party, said Kakao's actions, such as abuse of its market position and attempts to raise service prices, are concerning and that the party would not look on idly.

"As uncertainties about economic recovery persist due to the continued spread of the COVID-19 delta variant, (the KOSPI) fell on worries of regulation against local platform companies," Daishin Securities Lee Kyoung-min said.

Lee added online platform shares were further weighed down after financial authorities said Tuesday that some fintech companies' services would face new regulations later this month.

Kakao plummeted 10.06 percent to 138,500 won, and internet portal operator Naver tumbled 7.87 percent to 409,500 won.

Top cap Samsung Electronics added 0.26 percent to 76,300 won, and No. 2 chipmaker SK hynix gained 1.44 percent to 106,000 won.

Pharmaceutical giant Samsung Biologics retreated 2 percent to 931,000 won, and Celltrion fell 2.15 percent to 273,500 won.

Leading chemical firm LG Chem shed 0.26 percent to 756,000 won, while top automaker Hyundai Motor rose 0.24 percent to 213,000 won.

Video game giant Krafton surged 4.09 percent to 483,500 won.

The local currency closed at 1,166.7 won against the US dollar, down 8.9 won from the previous session's close. (Yonhap)