SEOUL, July 29 (Xinhua) -- South Korean stocks plunged about 6 percent Wednesday, triggering consecutive trading halts amid brutal tech sell-offs.
The benchmark KOSPI dived 360.42 points, or 5.98 percent, to close at 5,663.24, while the smaller KOSDAQ dropped 43.17 points, or 6.12 percent, to finish at 662.68.
After opening 1.09 percent higher, the KOSPI rallied to a high of 3.40 percent in early trading, only to reverse course about one and a half hours after the market opening.
The index fell as low as 12.63 percent at one point, activating sell sidecars on both the KOSPI and KOSDAQ markets.
The sidecar is activated when the benchmark futures index fluctuates for at least one minute by 5 percent for KOSPI and 6 percent for KOSDAQ, which also requires a 3 percent spot index move, leading to a temporary halt of program trading for five minutes.
Circuit breakers were also issued on both exchanges as the indices sustained a loss of over 8 percent for more than one minute.
It marked the first time that the circuit breakers were activated on both exchanges for the second straight session.
The circuit breaker is issued in stages when the KOSPI or KOSDAQ tumble by 8 percent, 15 percent and 20 percent.
The first two stages halt trading for 20 minutes, followed by a 10-minute single price auction, while the final stage instantly shuts down the market for the day.
The market meltdown was boosted by growing global skepticism over the sustainability of artificial intelligence (AI) infrastructure investments, and foreign investors' moves to dump heavyweight chipmakers such as Samsung Electronics and SK hynix.
The correction was also amplified by retail investors' focus on leveraged exchange-traded funds (ETFs) for Samsung Electronics and SK hynix as stock plunges forced involuntary liquidation.
Foreign and retail investors were net sellers on the KOSPI market, while institutional investors bought on the dip.
The South Korean won versus the U.S. dollar exchange rate finished its daytime session at 1,446.7 won per dollar as of 3:30 p.m. local time (0630 GMT), down 15.8 won from the previous session's daytime close.
Market bellwether Samsung Electronics and memory chip giant SK hynix retreated 5.23 percent and 9.61 percent.
The country's top automaker Hyundai Motor slipped 2.88 percent, and the largest battery maker LG Energy Solution went down 4.30 percent.
The No. 1 biopharmaceutical contract manufacturer Samsung Biologics fell 4.52 percent, and the leading aerospace and defense company Hanwha Aerospace declined 7.43 percent.
The biggest shipbuilder HD Hyundai Heavy Industries decreased 3.77 percent, and the energy infrastructure leader Doosan Enerbility was down 6.03 percent. ■