SK Hynix shares plunge 11% on US inflation and AI funding fears

SK Hynix shares plunged 11.1% to ₩1,262,000 on Thursday, extending a painful losing streak amid macroeconomic shocks and sector-specific concerns, marking one of the steepest single-day declines in recent months. The drop was triggered by higher-than-expected US September CPI data, reigniting fears the Federal Reserve may need further rate hikes, raising capital costs for AI infrastructure that drives demand for SK Hynix's high-bandwidth memory chips. Warnings from Broadcom and Intel CEOs that financing constraints, not chip shortages, could bottleneck AI expansion compounded the pressure, while Chinese rival CXMT's plans to commercialize a compact 4F² server DRAM architecture by year-end fueled competition fears. Foreign investors aggressively reduced exposure to Korean semiconductor stocks, with net sales of SK Hynix shares reaching hundreds of billions of won over consecutive sessions. The broader KOSPI opened about 5.6% lower, triggering circuit breakers and emergency trading restrictions on both KOSPI and KOSDAQ, while Samsung Electronics and Asian chipmakers also fell sharply in a sector-wide selloff.