Japan and South Korea Stocks Trim Gains After Surge; Kospi Holds 7,000 as SoftBank, SK Hynix Jump Over 3%

TradingKey - Japanese and South Korean stocks rally then retreat! KOSPI firmly holds 7,050 mark, Nikkei 225 pares gains to close lower, SoftBank and SK Hynix surge over 3%.

During the Asian trading session on September 9, Japanese and South Korean stock markets rallied before retreating, ultimately closing mixed. Among them, the KOSPI climbed above 7,100 intraday before pulling back to 7,051.64, ending up 1.44%. The intraday performance of the two major heavyweights diverged, but both ultimately closed higher: Samsung Electronics gained 0.28% to close at 270,500 Korean won, while SK Hynix surged 3.63% to 1,858,000 Korean won.

KOSPI index chart, Source: TradingView

After rallying in early trading, the Nikkei 225 Index subsequently trended downward, ultimately falling 0.19% to close at 65,142.73 points. Performance between the two heavyweights diverged: Kioxia fell 1.1% to close at 56,780 yen, while SoftBank bucked the trend with a 3.46% gain to end at 6,783 yen.

Boosted by overnight strength in US AI-related stocks and the Philadelphia Semiconductor Index, heavyweight tech stocks such as Samsung Electronics and SK Hynix showed strong early-session momentum. However, periodic escalation of tensions in the Middle East triggered a surge in crude oil prices, amplifying market concerns over inflation and supply chain disruptions, which led to a notable rally-and-retreat pattern across both Japanese and South Korean stock markets.