SK Hynix surpasses Samsung to become Korea's most valuable firm.

      For 25 years, Samsung Electronics was undisputedly the most valuable company in South Korea, and the question of its supremacy was never really up for debate. However, on Wednesday, that question emerged briefly before closing in a different light.

      During intraday trading, SK Hynix, the smaller of the nation’s two memory-chip manufacturers, surpassed Samsung in market capitalisation, taking the lead on the Korea Exchange for the first time since Samsung secured it in November 2000.

      By midday, SK Hynix's common shares reached approximately 2,057 trillion won, slightly exceeding Samsung's 2,051 trillion. The margin is narrow enough to note that if Samsung’s preferred shares, valued at around 180 trillion won, are included, the older company still holds a significant lead overall.

      Nonetheless, when considering common stock alone, the landscape has shifted, with SK Hynix shares rising more than 5 percent on that day, buoying the broader KOSPI index.

      The reason for this shift is clear. SK Hynix has spent the past two years as the leading supplier of high-bandwidth memory, the stacked chips that work alongside Nvidia’s accelerators to provide data rapidly enough to keep pace.

      Nvidia holds a dominant share of the AI training market, and SK Hynix has been its primary HBM partner, capturing the majority of the segment's revenue in recent quarters. This has transformed SK Hynix from the traditional second player into the company that the market currently values the most. Conversely, Samsung has been struggling to catch up in the crucial product area. While it has been qualifying its own HBM for Nvidia and is anticipated to secure a larger portion of the next-generation HBM4 orders, it has watched a competitor it once vastly outpaced close the gap and ultimately surpass it. In January, SK Hynix had already exceeded Samsung in annual profits for the first time, with market value being the last aspect to align.

      There’s another factor reflected in the share price. SK Hynix is preparing to list American depositary receipts in the United States, a move analysts attribute to its recent performance, which would offer international investors a simpler method to invest in the company without trading in Seoul. However, no specific date has been announced for this.

      This milestone illustrates how thoroughly the AI expansion has reshaped the Korean market. Together, SK Hynix and Samsung now represent approximately half of the KOSPI's total value, a concentration that has both advantages and disadvantages: it drove the index to record highs on Wednesday, but it also implies that a single weak quarter in memory demand could adversely impact the entire market. Ultimately, whether SK Hynix retains its newfound status will depend on how sustained the demand for AI memory remains.