Market-moving news for Tuesday, October 13, 2026

What happened

Per IDC data seen by Reuters, Nvidia's share of China's data-centre AI chip market fell to 34% in the first half of 2026 as U.S. export controls limited the range of products it can sell. Nvidia shipped 678,000 AI accelerators in China from January through June, down 44% from a year earlier. Huawei closed the gap substantially, shipping 572,000 AI accelerators — up from more than 300,000 a year earlier — for a 28% share. Beijing has additionally required Chinese companies to seek approval to import compliant Nvidia chips. Nvidia did not respond to a request for comment.

What happened

South Korea's KOSPI crashed more than 6% in intraday trading on Tuesday, Oct 13, breaking below the 6,000 level (5,996.16 at 10:40 a.m. KST, -6.08%), after opening 3.1% lower. The selloff triggered a sell sidecar at 9:47:58 a.m. KST — a five-minute suspension of program sell orders after KOSPI 200 futures fell 5.08% — the first on the main board in about two months. Samsung Electronics fell 6.79% to 233,500 won and SK Hynix tumbled 8.54% to 1.468 million won; foreign investors net sold 1.81 trillion won on the main board, with retail and domestic institutions absorbing the flow. The KOSPI is now down 10.1% over five sessions, its fifth straight decline. The catalyst is China's ChangXin Memory Technologies (CXMT): over the weekend it announced progress on a denser 4F² DRAM design (TrendForce estimates 30-50% density improvement) and plans to mass-produce next-generation server DRAM within the year, raising fears of expanded global memory supply. US chips sold off overnight ahead of it: the Philadelphia Semiconductor Index fell 2.67%, Micron fell 3.9% and Sandisk 6.0%.