SK Hynix on Monday overtook Samsung Electronics to become South Korea's most valuable listed company, marking a dramatic reversal of fortunes for a chipmaker that two decades ago nearly collapsed under debt. The company, now the dominant supplier of high-bandwidth memory (HBM) chips used in AI systems for customers such as ‌Nvidia and Alphabet's Google, has emerged as one of the biggest beneficiaries of the global AI boom, propelling a more than 340% rally in its shares this year and lifting ‌its market value above both Samsung Electronics and Micron. Shares of SK Hynix, now the world's most valuable memory chipmaker, traded up 5.7% to bring the company's market capitalisation to 2,082.5 trillion won ($1.35 trillion) as of 0347 GMT, compared with gains of ​0.4% in Samsung Electronics to 2,081.3 trillion won, excluding preferred shares.