SK Hynix just knocked Samsung off its perch on the KOSPI index — a position Samsung had held for a quarter century.
Shares in SK Hynix closed up 5.6% on Monday, lifting its market cap to 2,080.4 trillion won ($1.35 trillion), narrowly ahead of Samsung's 2,066.7 trillion won (excluding preferred shares). The gain capped a more than 340% rally this year, driven almost entirely by demand for high-bandwidth memory from Nvidia and other AI chip buyers. SK Hynix held 61% of the global HBM market in 2025, compared with 17% for Samsung and 21% for Micron. Samsung, for its part, contests the ranking, arguing that including preferred shares puts its cap at 2,246.4 trillion won.
The valuation flip is less a sudden upset than the payoff from a contrarian bet. SK Hynix kept investing in HBM through the 2023 memory downturn — when it posted a 7.73 trillion won annual operating loss — while Samsung reportedly ran into yield and qualification problems on its HBM3E chips that slowed Nvidia orders. Focus matters to investors too: SK Hynix makes memory and little else, whereas Samsung spans smartphones, displays, contract chipmaking, and appliances, diluting exposure to HBM's industry-leading margins.
The race is not over. Nvidia confirmed this month that all three major suppliers — Samsung, SK Hynix, and Micron — passed HBM4 certification for its Vera Rubin platform, and Samsung shipped the first 12-layer HBM4E samples in May. SK Hynix is projected to expand DRAM output by roughly 38% between 2025 and 2028 against Samsung's 17.5%, which would cut the current production gap from about 23% to under 10% — so the symbolic lead in market cap may prove easier to hold than the technical one.