The benchmark Korea Composite Stock Price Index(KOSPI) plunged nearly three-point-eight percent to close below three-thousand-860 amid prevailing AI bubble concerns. 

The main bourse closed Friday's trading at three-thousand-853-point-26, down 151-point-59 points, or three-point-79 percent from the previous day.

The KOSPI, which opened Friday at three-thousand-908-point-seven, two-point-four percent lower than Thursday's closing, dipped to three-thousand-838-point-46 around 1:51 p.m.

On Thursday, the main bourse climbed above the four-thousand mark after three days, jumping one-point-92 percent on the back of Nvidia's stronger-than-expected revenue.

Shares of the U.S tech giant, however, fell three-point-15 percent Thursday, local time, due primarily to growing doubts about its valuation after the company reported a rise in accounts receivable.

The tech-heavy KOSDAQ also ended Friday three-point-14 percent lower at 863-point-95.

The South Korean won depreciated seven-point-seven won against the greenback, trading at one-thousand-475-point-six won as of Friday's 3:30 p.m. close, its weakest since April 9.