SK Hynix Surpasses Samsung as South Korea's Most Valuable Company on AI Memory Demand

SK Hynix, the smaller of South Korea's two memory chip makers, passed Samsung Electronics in market capitalization during intraday trading on June 22, 2026, claiming the top spot on the Korea Exchange for the first time since Samsung took it in November 2000. The shift, driven by the AI memory boom, ended a 26-year reign.

By midday, SK Hynix's common shares were worth roughly 2,057 trillion won, narrowly ahead of Samsung's 2,051 trillion. The gap is slim: include Samsung's preferred shares, worth around 180 trillion won, and the older company remains larger overall. On common stock alone, the bellwether changed, and SK Hynix shares rose more than 5 percent on the day, pulling the wider KOSPI up with them.

High-Bandwidth Memory Dominance

The cause is not in dispute. SK Hynix has spent two years as the dominant supplier of high-bandwidth memory, the stacked chips that sit beside Nvidia's accelerators and feed them data fast enough to keep up. Nvidia controls the overwhelming share of the AI training market, and SK Hynix has been its principal HBM partner, commanding the majority of the segment's revenue in recent quarters.

• SK Hynix overtook Samsung in annual profit for the first time in January 2026.
• The company is preparing a U.S. listing of American depositary receipts, a move analysts have linked to its recent run.
• SK Hynix and Samsung together now account for roughly half of the KOSPI's entire value.
• A single soft quarter in memory demand can take the whole market down with it.
• MiTAC, a server vendor, showcased diamond-cooled servers and 52U racks at Computex 2026, highlighting the hardware push for AI.

Implications for the Korean Market

What the milestone marks, more than anything, is how completely the AI build-out has reordered the Korean market. The concentration cuts both ways: it lifted the index to records on Wednesday, and it means a single soft quarter in memory demand can take the whole market down with it. If SK Hynix keeps the crown is, in the end, a question about how long the appetite for AI memory holds.

Samsung, by contrast, has spent the cycle playing catch-up in exactly the product that matters. It has been qualifying its own HBM for Nvidia and is expected to win a larger slice of next-generation HBM4 orders, but for the moment it has watched a rival it once dwarfed close the distance and then cross it. The chipmaker has not put a firm date on its U.S. listing.