SK Hynix overtakes Samsung as South Korea’s most valuable company

SK Hynix overtook Samsung Electronics as South Korea’s most valuable listed company as investors kept rewarding the chipmaker most exposed to the AI build-out. SK Hynix shares rose 5.6% on Monday, lifting its market capitalization to 2,080.4 trillion won, or about $1.35 trillion, while Samsung Electronics slipped 0.14% to 2,066.7 trillion won, excluding preferred shares.

The reversal carries weight far beyond the trading screen. Samsung had held the top spot among South Korean listed companies since 2000, a sign of how durable its industrial dominance once looked. Now the balance has shifted toward SK Hynix, which has become the world’s most valuable memory-chip maker as high-bandwidth memory moves from a niche component to a core part of AI infrastructure.

High-bandwidth memory, or HBM, is the specialized chip used in systems that train and run large AI models, including those behind products such as ChatGPT. SK Hynix has built its edge by supplying HBM to major customers such as Nvidia and Alphabet’s Google, and its shares have surged more than 340% this year. Samsung said any market-cap calculation should include preferred shares; on that basis, its value stood at 2,246.4 trillion won at the close.

The size of SK Hynix’s turnaround gives the market move unusual force. The company was nearly sold to Micron in 2002 after debt from an aggressive expansion spree, then spent nearly a decade under creditor control. Its shares later fell as low as 135 won in 2003, turning it into a penny stock. In 2023, the company posted an annual operating loss of 7.73 trillion won during a severe memory-price slump, then bounced back with record annual operating profit of 23.5 trillion won in 2024.

The latest surge also reflects how quickly the AI supply chain is concentrating value in a few specialized players. Meritz Securities analyst Kim Sunwoo said the rise of customized AI memory changed the industry’s economics and helped SK Hynix establish itself as the market leader. Nvidia said on June 8 that SK Hynix would remain its largest memory partner and that it already buys “billions and billions of dollars each year” from the company, with spending set to grow further. On June 18, SK Hynix said it had shipped samples of its latest HBM chips to major customers, while its company history shows it began mass production of HBM3 in 2022, HBM3E in 2024 and shipped world-first 12-Hi stack HBM4 samples in 2025.

For South Korea’s chip industry, the shift is a reminder that leadership can move fast when the technology cycle changes. Samsung’s scale still matters, but SK Hynix now sits closest to the part of the market where AI demand is translating most directly into pricing power, revenue growth and investor enthusiasm.