Samsung Electronics shares fell 9.48% and SK hynix lost 11.06% on 15 October as South Korea’s Kospi closed down 7.57% at 5,554.23, Gotrade reported.
Key points
- The Kospi’s decline triggered a 20-minute halt, its tenth circuit breaker of 2026.
- US consumer prices rose 3.7% year on year in September, up from 3.4% in August.
- ChangXin Memory Technologies is targeting a server DDR5 module using its new DRAM architecture by the end of 2026.
Kospi triggers its tenth halt of 2026
Closing figures differed between reports of the session. Startup Fortune reported an 8% Kospi fall to 5,528.05, an 11.35% decline for SK hynix and a 9.70% drop for Samsung Electronics. Gotrade’s figures put SK hynix at 1.262 million won and Samsung at 210,000 won at the close.
The Kospi fell as much as 9% during the session. Trading stopped for 20 minutes from 12:38 p.m. local time after the index triggered its tenth circuit breaker of the year. The index had lost more than 16% over the preceding month and stood below the 9,000 level it crossed in June.
South Korean financial regulators held an emergency meeting during the sell-off. The regulators committed to steps to steady the market and held contingency measures in reserve if needed, according to Gotrade. Foreign investors had sold $676 million of South Korean equities in the previous session.
US inflation reaches 3.7% in September
US consumer prices rose 3.7% from a year earlier in September, against 3.4% in August and above economists’ expectations. The figures renewed concern about interest rates and the financing costs of AI infrastructure. The 10-year US Treasury yield stood at 5.11% early on 15 October, after briefly exceeding 5.32% on 14 October.
The yield had reached 5.35% earlier in October, its highest level since 2002. Investors were concerned that higher rates would increase the expense of building data centres and buying equipment, pressuring earnings and future investment. Lorraine Tan, Morningstar’s director of equity research for Asia, told the Associated Press that a perceived slowdown in AI spending growth could reduce demand for chips and equipment.
US AI-linked shares had fallen in the 14 October session. Nvidia lost 3.2%, AMD declined 5.7% and Broadcom gave up 3.1%. In Japan on 15 October, the Nikkei 225 closed down 4.90% at 64,425.90. Memory maker Kioxia fell 12.32%, while SoftBank Group lost 9.33%.
TSMC reports NT$1.494 trillion quarterly revenue
TSMC reported quarterly revenue of NT$1.494 trillion on 15 October, up 50.9% from a year earlier and above the top end of its forecast, Startup Fortune reported. The company described AI demand as strong. Its revenue for the first nine months of 2026 reached NT$3.899 trillion, an increase of 41.1% year on year.
TSMC makes logic chips, while Samsung and SK hynix sell memory. The Korean companies’ shares also faced concern about a potential new memory design from China. An earlier AI Affairs report covered SK hynix’s work on memory designs for AI inference beyond high-bandwidth memory.
ChangXin targets a 2026 server DDR5 module
ChangXin Memory Technologies presented a 4F² DRAM cell architecture at a Shanghai conference on 12 October. Samsung and SK hynix shares fell that day. Industry estimates put Samsung’s comparable design on its roadmap for 2028.
Startup Fortune put ChangXin’s share of the global DRAM market below 10%, against roughly 39% for Samsung and 25% for SK hynix, and reported that ChangXin had published no performance data or qualification results for the new architecture. It also identified restrictions on access to advanced manufacturing tools as a hurdle to producing the design at scale.
ChangXin Memory Technologies is targeting a server DDR5 module built around the architecture by the end of 2026.
