Korean stock market analysis from September 9, 2026 showing broad gains across AI-related sectors. KOSPI rose 1.40% and KOSDAQ jumped 2.28%, with strength spreading from AI data centers through optical communications, power cables, batteries, and semiconductors. Key gainers included battery material companies (SM Vattle +21.24%, LG Energy Solution, Samsung SDI) and optical communication firms (Mercury +30%) following Verizon's multi-billion dollar fiber optic supply contract with Corning.