South Korean stock investors' deposits at securities firms have plunged, according to industry data on Saturday, amid prolonged volatility in the stock market.

The amount of investor deposits came to 88.6 trillion won ($66.8 billion) as of Thursday, marking the lowest amount since Jan. 13, when they stood at 88.04 trillion won, according to the data from the Korea Financial Investment Association.

Compared with June 4, when they stood at 139.6 trillion won, investor deposits dipped by 51 trillion won, the data showed, reports Yonhap news agency.

The nation's benchmark Korea Composite Stock Price Index (KOSPI) hit the 9,000-point milestone in June but has seen sharp swings and high volatility since July.

South Korean shares closed slightly higher on Friday after plunging more than 3 percent in the previous session, as investors hunted for bargains in major chip stocks amid persistent concerns over investments in the artificial intelligence (AI) value chain. The Korean won strengthened against the U.S. dollar.

After choppy trading, the benchmark Korea Composite Stock Price Index (KOSPI) rose 16.53 points, or 0.3 per cent, to end at 5,550.30. The index opened 2.36 per cent lower, but individual investors, who were net sellers early in the session, turned to net buying.

Trade volume was light at 236 million shares worth 16.5 trillion won (US$12.4 billion), with decliners far outnumbering advancers 716 to 173.

Foreigners offloaded a net 98.3 billion won, while institutions and individuals bought a net 86.8 billion won and 4.5 billion won, respectively. Overnight, U.S. stocks closed mixed, with losses in major technology shares weighing on the broader market.

The Dow Jones Industrial Average rose 0.02 per cent, while the S&P 500 fell 1.21 percent and the tech-heavy Nasdaq Composite shed 2.6 per cent.

Micron Technology plunged 6.26 per cent, while Nvidia and Intel tumbled 4.4 per cent and 8.04 per cent, respectively. In Seoul, most large-cap shares traded mixed.