SEOUL, South Korea: SK Hynix overtook Samsung Electronics on June 22 to become South Korea's most valuable listed company, ending Samsung's 26-year hold on the top spot as investor demand for artificial intelligence-related chips drove a sharp rise in its shares.

SK Hynix shares closed 5.6 percent higher, lifting the company's market capitalization to 2,080.4 trillion won (US$1.35 trillion). Samsung's shares slipped 0.14 percent, giving it a market value of 2,066.7 trillion won, excluding preferred shares.

Samsung said its preferred shares should be included in any calculation of its market capitalization. Including those shares, Samsung's value stood at 2,246.4 trillion won at the close of trading.

SK Hynix has emerged as one of the biggest beneficiaries of the global AI boom because of its dominance in high-bandwidth memory, or HBM, chips used in AI systems by customers including Nvidia and Alphabet's Google.

The company's shares have risen more than 340 percent this year, pushing its market value above both Samsung and U.S. rival Micron. SK Hynix is now the world's most valuable memory chipmaker.

AI has transformed the semiconductor industry by turning specialized memory chips from widely traded components into critical parts of the infrastructure supporting products such as ChatGPT and other advanced AI models.

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

SK Hynix primarily makes memory chips, while Samsung also produces logic chips, smartphones, televisions, and other consumer electronics. Samsung had held the position of South Korea's most valuable listed company since 2000.

The milestone caps a dramatic turnaround for SK Hynix. In 2002, then-Hynix Semiconductor was close to being sold to Micron after debt had built up during an aggressive expansion drive. The deal fell through, and the company remained under creditor control for nearly a decade.

Its shares fell to as low as 135 won in 2003, leaving it regarded as a penny stock, or "Dongjeon-ju" in Korean.

The company suffered an operating loss of 7.73 trillion won in 2023 during a sharp downturn in memory prices. It returned to profit as AI investment accelerated, reporting a record operating profit of 23.5 trillion won in 2024.

Analysts credit its recovery to continued investment in HBM during the industry downturn. The chips are stacked vertically to deliver faster performance and lower power consumption, and are tightly integrated with AI processors.

SK Hynix held 61 percent of the global HBM market in 2025, compared with Samsung's 17 percent and Micron's 21 percent.

"What I really wanted to accomplish when we acquired Hynix was to transform it from a commodity memory producer into a mainstream semiconductor company whose products are indispensable," SK Group Chairman Chey Tae-won said.

SK Hynix is reportedly choosing Nasdaq for a planned U.S. listing, a move that could broaden its investor base and further raise its global profile.