The KOSPI on Wednesday slumped more than 4 percent to the 5,200 level after remarks by U.S. President Donald Trump. Losses widened in the afternoon, triggering sell-side sidecars on both markets and highlighting severe volatility.

The KOSPI closed down 244.65 points, or 4.47 percent, at 5,234.05. The index opened up 72.99 points, or 1.33 percent, at 5,551.69, but slid as far as 5,170.27 intraday as investor sentiment froze after a specific remark by Trump.

By investor type, foreign investors and institutions were net sellers of 136.9 billion won and 1.45 trillion won, respectively, weighing on the index. Retail investors were the sole net buyers, purchasing 1.21 trillion won.

Most top market-cap stocks were in the red.

Samsung Electronics closed down 5.91 percent at 178,400 won, while SK Hynix ended 7.05 percent lower at 830,000 won.

Hyundai Motor fell 4.61 percent, LG Energy Solution lost 0.61 percent, SK Square dropped 6.29 percent, Doosan Enerbility slid 6.02 percent and Kia declined 3.03 percent.

Samsung Biologics rose 0.83 percent and Hanwha Aerospace gained 6.30 percent.

The Kosdaq also ended down 59.84 points, or 5.36 percent, at 1,056.34.

As losses widened in the afternoon, sidecars were triggered on both the KOSPI and Kosdaq markets, halting the validity of sell orders.

In the Seoul foreign exchange market, the won was quoted at 1,520.60 per dollar, up 7.60 won, or 0.50 percent, from the previous session.