SK Hynix overtook Samsung Electronics on 22 June to become South Korea’s most valuable listed company by common-share market capitalisation, a position Samsung had held uninterrupted since 2000. Shares of SK Hynix closed 5.6% higher, lifting its valuation to 2,080.4 trillion won ($1.35 trillion), while Samsung’s common equity slipped 0.14% to 2,066.7 trillion won. Samsung noted that including preferred shares would raise its total to roughly 2,252 trillion won, but the common-stock milestone underscored the AI-driven reordering of the global chip industry.

The shift is rooted in the transformation of high-bandwidth memory (HBM) chips from interchangeable commodities into bespoke components tightly integrated with AI processors. SK Hynix has become the dominant supplier of these chips to Nvidia and Google, capturing 61% of the global HBM market by 2025, compared with 17% for Samsung and 21% for Micron, according to industry data. Kim Sunwoo, a senior analyst at Meritz Securities in Seoul, said the emergence of customised AI memory “fundamentally changed the industry’s economics” and allowed SK Hynix to establish market leadership. The company’s shares have surged more than 340% this year, reflecting the pricing power and higher barriers to entry that HBM affords relative to conventional DRAM.

The ascent also marks the culmination of a dramatic corporate turnaround. Two decades ago, the then-Hynix Semiconductor was on the verge of being sold to Micron under a mountain of debt, and its shares sank to 135 won in 2003. After years of boom-and-bust cycles, the company posted a 7.73 trillion won operating loss in 2023, only to rebound to a record 23.5 trillion won profit in 2024 as Microsoft, Google and Meta ramped up AI infrastructure spending. SK Group, the conglomerate that controls SK Hynix, has committed $75 billion to chip investments through 2028, with $60 billion earmarked for HBM. A new $12.9 billion packaging and testing plant in Cheongju is scheduled for completion by the end of 2027. Samsung, by contrast, remains diversified across logic chips, smartphones and consumer electronics, diluting its direct exposure to the AI memory windfall.

The next factual test for the new market leader will be its second-quarter earnings, expected in late July, which will reveal whether the HBM order pipeline and pricing environment can sustain the current growth trajectory. Industry attention will also focus on any capacity adjustments from Samsung and Micron as they seek to narrow the HBM gap.