SK Hynix suffered its largest single-day share decline in 18 years on the Seoul exchange on 13 July 2026, with domestic shares falling 15% — one trading session after a successful US ADR debut. Bloomberg Markets and Marketwatch TOP both reported the drop, noting that geopolitical shock and underlying leverage concerns contributed to the severity of the decline. The fall extended into a record low for the stock on Korean exchanges, Bloomberg Markets reported.
The SK Hynix plunge triggered a broad selloff across the semiconductor sector. The SOX semiconductor index fell alongside Micron and other chip manufacturers, according to Marketwatch TOP. Bloomberg Markets reported that tech stocks faced wider selling pressure connected to the SK Hynix weakness, with the decline characterised as sector-wide rather than isolated to the Korean memory chip producer.
SK Hynix domestic shares (000660.KS on the Seoul exchange) and its US ADR (SKM) are directly implicated in the reported moves. Micron (MU) and the SOX semiconductor index registered concurrent declines tied to the SK Hynix-led selloff, as reported by Marketwatch TOP. The broader KOSPI index also came under pressure, per Bloomberg Markets.
TSMC and ASML are scheduled to report quarterly results in the same week, with Bloomberg Markets noting the earnings arrive against a backdrop of significant market volatility in AI-related tech stocks and investor concerns about semiconductor sector demand and valuation.
Sources: Bloomberg Markets, Marketwatch TOP