TradingKey - During the early Asia-Pacific trading session on July 9, memory chip stocks collectively surged. Japanese memory chip leader Kioxia saw its stock price jump over 10% at one point, while South Korea's SK Hynix rose over 8% and Samsung Electronics climbed over 4%, driving a rapid recovery in the Japanese and South Korean semiconductor sectors from the sharp sell-off in the previous trading session.
From the real-time market action, Kioxia has emerged as the core leader of this rebound. Data shows that Kioxia's stock price peaked at 79,950 yen in morning trading, a gain of over 10%. Market enthusiasm for the stock primarily stems from two main drivers: first, the rising demand for NAND flash memory driven by AI data centers; second, the expected significant increase in Kioxia's weight in the TOPIX index, which could trigger sustained passive capital inflows. Previous reports indicated that Kioxia's TOPIX weight is expected to triple, making it one of the most watched stocks by index funds in the Japanese semiconductor sector.

Kioxia Stock Price Daily Chart, Source: TradingView
South Korea's twin memory giants also rebounded sharply. SK Hynix's stock price rose over 8% at one point in morning trading, reaching an intraday high of 2.227 million won; Samsung Electronics climbed over 4% intraday, reaching a high of 291,500 won. Driven by Samsung Electronics and SK Hynix, South Korea's KOSPI index opened more than 3% higher, as investors bought the dip following the sharp decline in chip stocks during the previous trading session.
The immediate catalyst for this rebound is the previous concentrated sell-off in memory chip stocks. Due to market concerns over potential overheating in AI infrastructure investment, the possibility of memory chip prices peaking, and Samsung Electronics' strong earnings failing to exceed excessively high expectations, investors had temporarily taken profits on the memory sector. The US memory sector also took the lead in recovering overnight. On July 8, Eastern Time, Micron Technology ( MU) closed up 1.11%, SanDisk ( SNDK) closed up 6.77%, and Western Digital ( WDC) closed up 3.42%. Looking at both US stocks and today's Japanese and South Korean markets, capital has not abandoned the AI memory theme, but rather viewed the previous day's decline as an opportunity to reposition.