South Korean shares surged on Wednesday, October 21, 2026. Technology stocks recovered sharply from a steep sell-off driven by prior concerns over artificial intelligence investment and profitability. The robust rebound followed positive momentum on Wall Street, where stronger-than-expected corporate earnings supported overall investor sentiment across global markets.
Seoul’s benchmark Korea Composite Stock Price Index (KOSPI) climbed 3.29 percent, or 182.92 points, to close at 5,735.66. The sharp recovery successfully reversed a significant portion of Tuesday’s 3.73 percent decline. Elsewhere in the region, Japan’s Nikkei 225 advanced 0.9 percent to 64,621.24, while Taiwan’s Taiex gained 1.3 percent.
Market Activations and Trading Activity
The intensity of the morning rally prompted the Korea Exchange to activate a buy-side sidecar shortly before 11 a.m. This temporary measure suspended program buying for five minutes after KOSPI 200 futures rose more than 5 percent, marking the first such activation in two months.
Trade volume reached 214.35 million shares worth 17.16 trillion won ($12.96 billion). Decliners narrowly outnumbered advancers 487 to 372. Foreign investors provided strong upward momentum by purchasing a net 659.96 billion won. Meanwhile, retail and institutional investors offloaded net figures of 1.13 trillion won and 72.22 billion won, respectively.
Semiconductor Giants Lead the Recovery
The Wednesday session stood in stark contrast to Tuesday, when SK Hynix fell 3.5 percent and Samsung Electronics declined 1.8 percent amid panic over debt-fueled artificial intelligence expenditures. Investor anxiety subsided following strong earnings reports from US AI server manufacturer Super Micro Computer, which alleviated profitability worries.
Market bellwether Samsung Electronics rose 5.67 percent to finish at 223,500 won, while rival chipmaker SK Hynix advanced 5.81 percent to 1.29 million won. SK Corp., the holding company of SK Group, jumped 12.62 percent to 482,000 won, bouncing back from an 8 percent plunge during the previous session. LS Electric also surged 7.02 percent to 166,100 won, supported by strong third-quarter earnings driven by high demand from AI data centers.
Broader Market Movements and Foreign Exchange
Other major equities experienced mixed results. National flag carrier Korean Air gained 1.9 percent, and Hyundai Steel moved up 2.14 percent. Conversely, top automaker Hyundai Motor dipped 0.16 percent, and leading steelmaker POSCO Holdings declined 0.33 percent.
In the defense sector, LIG D&A plunged 9.03 percent to 498,500 won. This drop occurred after South Korea’s arms procurement agency barred the defense firm from bidding on state defense contracts for two years due to ongoing bribery allegations.
In the currency market, the South Korean won strengthened slightly against the US dollar. It traded at 1,325.2 won at the close, up 0.8 won from the previous session.
