Chinese memory fears sink the Kospi 5.46%, rattling Taiwan and Japan

According to Yonhap via the Korea JoongAng Daily, the index opened 3.1% lower, and a sell-side sidecar was triggered when the loss exceeded 5% for more than a minute. KED Global says the index dipped below 6,000 intraday, and this was the first sell-side sidecar in about two months. Institutions bought a net 1.69 trillion won and retail investors 2.23 trillion, absorbing the foreign selling; the won weakened by 10 won to 1,345.1 per dollar. Han Ji-young of Kiwoom Securities cited questions over OpenAI's revenue and the end of domestic chipmakers' share buybacks alongside the CXMT news.

The selling spread across the region on 13 October. The Taiex fell 960.65 points (1.95%) to 48,341.31; foreigners made their third-largest net sale on record at NT$165.34 billion, and the Taiwan dollar closed weaker than 32 per US dollar for the first time in two months. The Taipei Times says the Nikkei 225 fell 1.8%, with Kioxia down more than 13%, Advantest more than 8% and Tokyo Electron more than 7%. The same report says a rumour of a possible delay in Nvidia's Vera Rubin shipments deepened the sell-off; the rumour could not be verified.

The technology is moving more slowly than the pricing. CXMT said in Shanghai on 10 October that its first 4F² product would be a DDR5 server module due at year-end, but gave no speed, capacity or firm date. Industry sources cited by Newsis say 4F² cuts cell area by about 33% on paper compared with 6F²; Samsung and SK hynix do not plan to bring the structure into mass production until around 2028 because of yield and cost. The $3.35 billion sold on 13 October prices not today's technology gap but how many more years pricing power in server memory can be defended.