SK Hynix, Samsung and SoftBank fell after a sell-off in U.S. chip stocks.
Why it matters: The declines show how quickly concerns about semiconductor valuations and AI investment are moving across markets. Investors are also assessing whether Chinese memory-chip advances could affect future pricing, market share and margins.
- A Reuters report republished by MarketScreener put SK Hynix's decline at about 10% and Samsung Electronics' at 8% in Seoul.
- The Kospi fell more than 5%, while SoftBank Group dropped roughly 8% to 9% in Tokyo.
- U.S. stocks fell Monday: Micron 3.9%, AMD 2.3%, Broadcom 1.9% and Nvidia 1.3%.
- CXMT said its fifth-generation DRAM platform entered mass production on September 20, 2026.
Semiconductor and AI-linked shares fell across Asia on Tuesday, October 13, 2026, after a weaker U.S. session. CNBC reported intraday declines of more than 8% for SK Hynix and about 6.7% for Samsung Electronics. A MarketScreener page republishing a Reuters report cited declines of about 10% and 8%, respectively. The figures reflect different reported points during the trading session, rather than a verified common closing-price comparison.
SoftBank Group also fell roughly 8% to 9% in Tokyo. The company is exposed to the AI investment cycle through holdings including Arm and OpenAI. CNBC reported that SoftBank had committed up to $30 billion in additional investment in OpenAI and reported a net asset value of ¥40.1 trillion as of March 31, 2026.
The losses followed Monday's U.S. session. Micron Technology fell 3.9%, AMD declined 2.3%, Broadcom lost 1.9% and Nvidia fell 1.3%. The Nasdaq Composite dropped 0.4%, while the Philadelphia Semiconductor Index fell about 2.7%, according to the Reuters report republished by MarketScreener.
Investors are weighing whether large AI infrastructure investments can support current technology valuations and future earnings. Market concern about China's ChangXin Memory Technologies, or CXMT, was another factor for established memory-chip companies. CXMT said its G5 DRAM platform entered mass production on September 20, 2026. The company said the platform delivered at least 50% higher die-per-wafer output than its previous platform.
By the numbers
- About 10% - Reuters-reported decline for SK Hynix
- 8% - Reuters-reported decline for Samsung Electronics
- ¥40.1 trillion - SoftBank's reported net asset value as of March 31, 2026
Yes, but: The reported stock declines came from different points during the trading session, so they should not be treated as directly comparable closing prices. The available reports also describe CXMT's production milestone and investor concern, not a demonstrated change in market share or pricing.