SK Hynix drops 15% in Seoul after Nasdaq IPO; chip sector rout triggered by memory cost concerns

SK Hynix, which had surged 13% in its Nasdaq debut on Friday July 10, tumbled 15% in Seoul trading on Monday July 13, marking the company's worst day on record and triggering a broader semiconductor selloff. South Korea's KOSPI index fell 8.7% to 8,806.93, closing near the day's lows. The rout was sparked by a brokerage report suggesting SK Hynix may not meet quarterly profit targets and broader concerns that elevated memory chip prices could dampen enterprise spending. The South Korean index hit circuit breakers 35 times this year—more than the 26 halts during the entire 2008 financial crisis.

The selloff cascaded globally, with memory chip stocks leading U.S. declines: Micron Technology (down 4.3%) and SanDisk (down 5.5%) fell sharply, dragging the Roundhill Memory ETF (DRAM) down 9%. Broader chip stocks also retreated: Nvidia, AMD, and Broadcom dipped 2-3%, while the iShares Semiconductor ETF (SOXX) fell 2%. The semiconductor index shed over 11% since June's record high. Geopolitical tension—renewed U.S.-Iran conflict and the Strait of Hormuz blockade threat—sent crude oil up 4.6% to ~$75/barrel, exacerbating concerns about data center power costs.

For infrastructure teams, the move underscores the tension between HBM supply scarcity (driving premium pricing) and enterprise margin compression. Memory costs have become load-bearing for AI data center economics: SanDisk, Micron, and SK Hynix have steered wafer capacity toward HBM, pulling commodity DRAM supply. If enterprises begin to moderate AI infrastructure spending due to price sensitivity and energy costs, the virtuous cycle that powered 2026's AI capex boom may face a structural headwind.