SK Hynix has overtaken Samsung Electronics as South Korea's most valuable company, driven by soaring demand for specialized memory chips used in AI systems.

What happened: SK Hynix's shares traded up 5.7% on June 22, bringing its market capitalization to 2,082.5 trillion won ($1.35 trillion（約220兆円）), surpassing Samsung Electronics at 2,081.3 trillion won. The chipmaker, which supplies high-bandwidth memory (HBM) chips to AI customers such as Nvidia and Google, has posted a more than 340% share rally this year and is now the world's most valuable memory chipmaker.

Why it matters: SK Hynix has emerged as one of the biggest beneficiaries of the global AI boom. The shift in the semiconductor industry—where customized AI memory has moved from a commodity into a critical component powering applications like ChatGPT—has fundamentally changed economics and allowed SK Hynix to establish itself as the market leader. This marks a dramatic reversal for a company that two decades ago nearly collapsed under debt and was on the verge of being sold to Micron in 2002.

What to watch: SK Hynix reported an annual operating loss of 7.73 trillion won in 2023 during a severe memory-price downturn, but recovered to post an annual operating profit of 23.5 trillion won in 2024, described as a record at the time. Samsung has stated that its market capitalization calculation should include preferred shares, which would bring its value to around 2,252 trillion won.