Samsung Electronics shares plunge 9% on US inflation and AI investment doubts

Samsung Electronics shares plunged 9.2% to ₩210,750 on Thursday, driven by higher-than-expected US inflation data and growing doubts about the AI investment cycle. The selloff intensified after research firm Gartner warned that $3.5 trillion in global AI infrastructure investments face asset impairment risk by 2030. The US inflation reading increased expectations that the Federal Reserve may raise interest rates further, raising financing costs for high-valuation tech stocks. Gartner's warning directly challenged the demand thesis behind Samsung's memory chip division, which had driven record preliminary operating profit of 107.4 trillion won in Q3 2026. Foreign investors accelerated their exits, with institutional buyers unable to absorb the selling pressure. The broader Korean market suffered heavily, with the KOSPI opening at 5,673.01, down 5.6% from the previous close of 6,008.81. The Korea Exchange activated a sell-side sidecar after KOSPI 200 futures fell over 5%. The index headed for its seventh consecutive losing day, the longest streak in about two years.