South Korea's KOSPI jumped more than 6 percent to reclaim the 6,000 level for the first time in 10 trading sessions. Buying concentrated in heavyweight semiconductor shares after strong SK hynix results, while foreign investors and institutions net bought more than 1.7 trillion won, pushing the index higher.

On Oct. 28, the KOSPI closed up 374.10 points, or 6.63 percent, at 6,012.44. It was the first time in 10 sessions that the KOSPI regained the 6,000 level on a closing basis. The index opened up 125.51 points, or 2.23 percent, at 5,763.85 and quickly widened its gains.

The KOSPI's gain was the biggest since July 31, when it rose 17.91 percent, and the point gain was the largest since Aug. 20, when it climbed 381.41 points.

The sharp rise triggered a buy-sidecar curb for a second straight session. The Korea Exchange suspended the effectiveness of program buy orders on the main board for 5 minutes after KOSPI 200 futures held gains of 5.17 percent over the reference price for more than 1 minute from 9:54:24 a.m.

By investor type, foreign investors net bought 815.8 billion won and institutions net bought 960.8 billion won. Retail investors net sold 1.80 trillion won, taking profits.

Among the top market-cap stocks, strength in semiconductor shares stood out.

SK hynix ended up 10.89 percent at 1,487,000 won, and Samsung Electronics gained 9.01 percent to 242,000 won.

Elsewhere, SK Square rose 11.23 percent, Samsung Electro-Mechanics climbed 8.74 percent and Samsung Life gained 8.82 percent. KB Financial Group rose 4.34 percent, while Hyundai Motor added 1.89 percent and LG Energy Solution gained 1.83 percent. Samsung Biologics fell 0.15 percent.

Semiconductor stocks were boosted by SK hynix's release of third-quarter results. As results beat market expectations and hopes persisted for demand for AI memory such as high-bandwidth memory, buying spread to large semiconductor shares including Samsung Electronics.

The KOSDAQ also rose. It closed up 27.45 points, or 3.69 percent, at 771.28.

In the Seoul foreign exchange market, the won was at 1,338.20 per dollar, down 10.20 won from the previous session.

Local stocks have been rebounding quickly after a sharp fall, led by heavyweight semiconductor shares. After rising 3.09 percent the previous day, the KOSPI jumped 6.63 percent on the day, and volatility remained high, including a buy-sidecar curb being triggered for two straight sessions.

Han Ji-young (한지영), a researcher at Kiwoom Securities, said, "Even shareholder returns alone could improve short-term investor sentiment and the supply-demand environment across the KOSPI beyond the semiconductor sector, which could make the significance of this SK hynix earnings report greater than before."