Kospi Rebound Triggers Buy Sidecar as Samsung Electronics, SK Hynix Jump More Than 7%

South Korea's Kospi rebounded sharply, led by heavyweight semiconductor shares, triggering a buy sidecar that temporarily suspends the validity of program buy orders on the benchmark stock market.

The Korea Exchange said the mechanism was activated at 10:51:56 a.m. on October 21 after Kospi 200 futures surged. At the time, the contract stood at 904.84, up 44.94 points, or 5.22%, from the reference level of 859.90.

A buy sidecar is triggered when Kospi 200 futures rise more than 5% from the reference price and hold that level for one minute. The measure is designed to limit spillover from sharp swings in the futures market into the cash market. Once activated, it suspends the validity of program buy orders for five minutes. On October 21, the halt remained in place until 10:56:56 a.m.

The rebound appeared to be driven by bargain hunting after the previous session's steep selloff. The Kospi had fallen to its lowest level in six months in the prior session, while foreign and institutional investors both turned net buyers, supporting the index's rise. Buying was especially concentrated in semiconductor heavyweights including Samsung Electronics and SK Hynix.

Samsung Electronics was trading at 226,750 won, up 15,250 won, or 7.21%, from the previous session. SK Hynix rose 93,000 won, or 7.60%, to 1,316,000 won. SK Square jumped 6.61% to 790,000 won. Other major Samsung Group affiliates were also broadly higher, with Samsung C&T up 6.18%, Samsung Electro-Mechanics gaining 3.29% and Samsung Life Insurance rising 3.16%.

The Kosdaq index also extended gains. At the same time, it was up 14.74 points, or 1.88%, at 796.71. After opening at 793.40, the index climbed as high as 803.68, then fell back to 785.53 before rebounding again. By investor type, individuals and institutions were net buyers of 48.9 billion won and 49.7 billion won, respectively, while foreigners were net sellers of 101.3 billion won.

On the Kosdaq market, semiconductor equipment and parts makers led the advance. EO Technics rose 4.16% to 438,500 won, while Jusung Engineering gained 3.99%, Wonik IPS added 2.23% and Simtech advanced 1.85%. EcoPro BM climbed 3.61% to 109,000 won, and Alteogen rose 3.25% to 238,500 won.

Meanwhile, in Seoul's foreign-exchange market, the won was trading at 1,327.50 per dollar, up 1.50 won from the previous session.