SEOUL, March 23 (Xinhua) -- South Korean stocks dropped over 6 percent on Monday amid escalating Middle East tensions that triggered a sell sidecar.
The benchmark KOSPI tumbled 375.45 points, or 6.49 percent, to close at 5,405.75, while the smaller KOSDAQ dived 64.63 points, or 5.56 percent, to finish at 1,096.89.
The stock market sharply reacted to U.S. President Donald Trump's ultimatum regarding the Strait of Hormuz, fueling fears of an all-out energy war.
In the morning session, the extreme volatility activated a sell-side sidecar as the KOSPI 200 futures plunged over 5 percent.
The sidecar refers to a temporary halt of program trading orders for five minutes that is triggered when the KOSPI 200 futures rise or fall by more than 5 percent.
Foreign and institutional investors led the sell-off, while retail investors prevented the deeper rout through a dip-buying in both the KOSPI and the KOSDAQ.
The South Korean won versus U.S. dollar exchange rate finished its daytime session at 1,517.3 won per dollar as of 3:30 p.m. local time (0630 GMT), up 16.7 won from the previous session's daytime close.
The exchange rate surpassed the 1,510 won mark for the first time since 2009.
Market bellwether Samsung Electronics and memory chip giant SK Hynix ended 6.57 percent and 7.35 percent lower each.
The country's top automaker Hyundai Motor tumbled 6.19 percent, and the largest battery maker LG Energy Solution decreased 5.19 percent.
The No. 1 biopharmaceutical contract manufacturer Samsung Biologics fell 4.87 percent, and the leading aerospace and defense company Hanwha Aerospace dipped 3.18 percent.
The biggest shipbuilder HD Hyundai Heavy Industries went down 10.20 percent, and the energy infrastructure leader Doosan Enerbility was down 8.12 percent. ■