SK Hynix dominates HBM market as US ADR debut fuels AI memory surge

South Korean memory maker SK Hynix listed its American Depositary Receipts on the Nasdaq, raising about $26.5 billion and becoming the largest first‑time U.S. offering by a foreign firm. The company now holds roughly 56 % of the high‑bandwidth memory (HBM) market, a critical component for Nvidia’s AI accelerators, and has announced a partnership with Nvidia to supply future HBM generations.

SK Hynix plans to double its wafer capacity over the next five years, citing continued supply constraints that could last until at least 2030. Revenue from DRAM and HBM has surged, with quarterly sales up nearly 200 % and margins expanding to the high‑70s. Analysts note the business remains cyclical and that rapid capacity expansion could risk oversupply if AI‑related capex slows.

In Korea’s stock market, SK Hynix’s market valuation briefly overtook Samsung Electronics, reflecting investor focus on pure AI‑memory exposure. The stock’s recent volatility, including a sharp pull‑back after a rally, is attributed to profit‑taking rather than a fundamental slowdown. A Bank of America report questioned the feasibility of the company’s announced capacity expansions, suggesting only a fraction may materialize by 2028.

Overall, SK Hynix’s U.S. listing, dominant HBM share, and aggressive expansion plan place it at the centre of the AI‑driven memory boom, while market observers watch for potential supply‑demand imbalances and valuation risks.