Something unusual happened in South Korea’s equity market this month. SK Hynix, a company that spent decades playing second fiddle to Samsung Electronics, quietly surpassed it to become the country’s most valuable listed company. Its market capitalization hit 2,080.4 trillion won, roughly $1.35 trillion, on June 23. That’s not a typo.
The catalyst is high-bandwidth memory chips, the specialized silicon that powers AI training and inference workloads. SK Hynix shares have surged more than 300% year-to-date, a run that has single-handedly turned Seoul’s stock market into the global market’s most sensitive AI barometer.
The great Korean chip swap
SK Hynix controlled approximately 61% of the global HBM market in 2025, dwarfing Samsung’s 17% share and Micron’s 21%. In English: for every dollar spent on the memory chips that make AI possible, SK Hynix captured roughly three out of five of them.
SK Hynix’s operating profit more than doubled to 47.2 trillion won in 2025, fueled by insatiable demand from hyperscalers building out AI infrastructure. Prices for next-generation HBM4 chips have commanded a 20-30% premium earlier in 2026, pouring additional fuel on an already blazing fire.
