[DigitalToday reporter Sang-yeop Oh (오상엽)] Sell sidecars were triggered on the KOSPI and Kosdaq. Both markets then slid more than 8 percent, setting off first-stage circuit breakers.

On July 28, the KOSPI opened at 6,400.27, down 355.48 points, or 5.26 percent, from the previous session. Selling later widened around heavyweight chipmakers such as Samsung Electronics and SK Hynix, quickly deepening losses during the session.

The Korea Exchange on Tuesday triggered a sell sidecar, a temporary suspension of program sell orders, on the main bourse at 9:06 a.m.

At the time, mini KOSPI 200 futures were at 1,001.54, down 6.42 percent from the benchmark price of 1,070.34. Program sell orders were suspended for 5 minutes.

A sell sidecar was also triggered on the Kosdaq market at 9:14 a.m. It met the trigger threshold as Kosdaq 150 futures fell 6.07 percent from the previous close and the Kosdaq 150 dropped 5.92 percent.

Selling did not ease despite the sidecar trigger, and a first-stage circuit breaker was triggered on the KOSPI at 10:13 a.m.

At the time, the KOSPI was at 6,213.51, down 542.24 points, or 8.02 percent, from the previous close of 6,755.75. Trading in all stocks listed on the main bourse was halted for 20 minutes.

It was the KOSPI's eighth circuit breaker this year and the 14th since the system was introduced. The Korea Exchange cited weakness in U.S. semiconductor-related stocks as the main reason.

A first-stage circuit breaker was also triggered on the Kosdaq at 12:01:12 p.m. At the time, the Kosdaq was at 702.91, down 61.95 points, or 8.09 percent, from the previous session.

Trading across the entire market was halted for 20 minutes after the Kosdaq stayed down more than 8 percent from the previous close for 1 minute.

After a first-stage circuit breaker is triggered, the second stage is activated if the index falls at least 15 percent from the previous session and declines at least 1 percent further from the first-stage trigger level. If the index falls at least 20 percent and drops at least 1 percent further from the second-stage trigger level, a third stage is triggered and trading is fully terminated.

Around midday, top stocks by market capitalisation also fell sharply across the board.

Samsung Electronics traded at 220,500 won, down 33,500 won, or 13.19 percent, from the previous session. SK Hynix was at 1,564,000 won, down 252,000 won, or 13.88 percent.

SK Square slid 15.24 percent and Samsung Electro-Mechanics tumbled 18.04 percent. Samsung Electronics preferred shares fell 12.07 percent, Samsung Life dropped 10.11 percent and Hyundai Motor lost 9.55 percent.

LG Energy Solution fell 5.71 percent, KB Financial dropped 2.72 percent and Samsung Biologics was down 1.17 percent.