SK Hynix momentarily became South Korea's most valuable company on June 22, 2025, ending Samsung Electronics' dominance that had stretched back to 2000. At 03:47 GMT that day, SK Hynix's market cap reached 2,082.5 trillion won ($1.35 trillion), while Samsung stood at 2,081.3 trillion won. The flip didn't last, but the symbolic shift underscores a year of extraordinary gains for the memory-chip maker, which is now valued higher than Berkshire Hathaway, Eli Lilly, Walmart, and even Bitcoin.
The numbers behind the flip
SK Hynix shares have surged roughly 345% year-to-date in 2025, compared with Samsung's 194% gain. The company's rise from near-collapse in 2002 — when Hynix Semiconductor almost sold itself to Micron and shares traded as low as 135 won in 2003 — to the top of the Korean market is a story of focus. While Samsung juggles logic chips, smartphones, and consumer electronics, SK Hynix bet heavily on memory, specifically high-bandwidth memory (HBM) used in AI systems.
AI memory changes the game
High-bandwidth memory has become the bottleneck for AI training and inference, and SK Hynix has locked down supply deals with Nvidia and other hyperscalers. Kim Sunwoo, senior analyst at Meritz Securities, said in a note: 'The emergence of customised AI memory fundamentally changed the industry's economics and allowed SK Hynix to establish itself as the market leader.' The company's HBM3 and next-generation HBM4 chips command premium pricing, and capacity is sold out well into 2026.
Korean retail investors pile in
The rally has drawn heavy retail participation. Korean individual investors have been rotating aggressively into chip stocks throughout 2025, dumping positions in other sectors to buy SK Hynin and Samsung. The Korea Exchange saw record daily trading volumes in semiconductor names, with SK Hynix accounting for a disproportionate share of retail flow. The shift mirrors a broader global appetite for AI hardware plays, but at home it's particularly intense, with mom-and-pop traders treating SK Hynix as a proxy for the AI trade.
What comes next
SK Hynix still faces the cyclical nature of memory pricing — a downturn could erase years of gains quickly. Samsung, meanwhile, is pouring billions into its own HBM production lines and advanced packaging to catch up. The fight for the top spot in Korea is far from settled, but for one morning in June, the chipmaker that nearly died two decades ago stood at the very top.
