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SK Hynix overtook Samsung Electronics on Monday to become South Korea's most valuable listed company, ending a 26-year run at the top for the consumer electronics and semiconductor giant.

At the close, SK Hynix shares had risen 5.6%, pushing its market capitalization to 2,080.4 trillion won ($1.35 trillion), while Samsung ended the session down 0.1%, leaving its market value at 2,066.7 trillion won. Samsung said in a statement that any calculation of its market capitalization should include preferred shares โ€” on that basis, its value stood at 2,246.4 trillion won at the close.

The milestone reflects SK Hynix's rise as the dominant supplier of high-bandwidth memory chips, which are used in AI systems built by customers including Nvidia and Alphabet's Google. SK Hynix stock has gained more than 340% this year. In the global HBM market as of 2025, SK Hynix commanded a 61% share, with Micron at 21% and Samsung trailing at 17%, according to Reuters.

"The emergence of customised AI memory fundamentally changed the industry's economics and allowed SK Hynix to establish itself as the market leader," Kim Sunwoo, a senior analyst at Meritz Securities, said.

The reversal is a remarkable turn for a company that nearly collapsed two decades ago. A potential sale to Micron loomed over the company in 2002, when what was then called Hynix Semiconductor had buckled under debt taken on during a period of rapid growth. After those talks collapsed, creditors ran the company for close to ten years. Its stock traded as low as 135 won in 2003. The company posted an operating loss of 7.73 trillion won for 2023, when a brutal slump in memory prices weighed on results, but surging AI investment helped it swing to a then-record operating profit of 23.5 trillion won the following year.

SK Hynix crossed a $1 trillion market capitalization for the first time in late May, joining Samsung and Taiwan Semiconductor Manufacturing Co. as the only Asian companies to reach that threshold. The company is also pursuing a U.S. listing through American depositary receipts, with a debut on the Nasdaq as early as August. In a book published in January, Chey Tae-won, the SK Group chairman who pushed through the Hynix acquisition despite internal opposition, laid out his vision for what the deal was meant to achieve. His ambition, he wrote, was to move the company away from selling interchangeable commodity chips toward making products that customers could not do without. "HBM is different. If SK Hynix's HBM is replaced with another product, the AI system may not function properly," he said.