SK Hynix tops $1 trillion as AI chip rally lifts KOSPI

SK hynix briefly crossed the $1 trillion market-value mark for the first time as a wave of buying in AI-linked semiconductors turned a once-cyclical memory supplier into one of the market’s defining winners. At 9:39 a.m. in Seoul, the stock was up 9.06% at 2,238,000 won, implying a market capitalization of about 1.589 quadrillion won, or $1.05 trillion. Later in the session, the shares rose as much as 14.9%, lifting the company’s market value to about 1,680 trillion won, or $1.12 trillion, and helping drive the KOSPI to a record high.

The rally has been powered by a tightening memory market shaped by AI data centers. Demand for high-end chips used in AI chipsets and server systems has absorbed inventory that would ordinarily flow to smartphones, laptops and automobiles. Memory-chip prices doubled in the first quarter from the previous period, and prices were forecast to climb as much as 63% in the current quarter. TrendForce said conventional DRAM contract prices in the first quarter rose 90% to 95% from the previous quarter, while NAND flash prices increased 55% to 60%, with North American cloud-service-provider demand also pushing up enterprise SSD orders.

The move put South Korea in a new position in global markets. Samsung Electronics had crossed $1 trillion in market value on May 6, and Micron Technology did so on May 26, making SK hynix the third Asian company in history to reach the milestone after TSMC and Samsung. South Korea also became the first country outside the United States to have more than one company valued above $1 trillion. The rally was broad enough to lift Samsung shares as much as 8%, while the KOSPI briefly hit a sidecar trigger that paused some algorithmic trading.

The bigger question is whether the valuation is being driven by durable demand or a shortage that could eventually ease. Analysts expect demand to stay ahead of supply through 2028, which would keep pricing elevated and support chipmakers’ profits. SK hynix has said its 2026 outlook sees the semiconductor market entering a transitional period as AI infrastructure expands, with HBM3E and HBM4 expected to fuel an AI memory supercycle. The company has also been described as effectively sold out through 2026, underscoring how deeply AI has reordered the memory supply chain and how much of the AI economy now depends on chips that sit below the headline names.