SK Hynix shares closed 9.3 per cent higher in Seoul on Wednesday, taking the South Korean memory maker past $1 trillion in market capitalisation for the first time in its history and confirming a re-rating of the memory chip industry that has now lifted three Asian-Pacific names into the trillion-dollar club inside a month. Micron Technology had crossed the same line on Tuesday after a UBS note argued the Boise-based maker could double over the next twelve months. Samsung Electronics breached the threshold in early May.
The three memory firms are now collectively valued above three trillion dollars, a figure that exceeded the combined market value of the entire global memory industry as recently as October 2024. SK Hynix shares have risen 250 per cent since the start of 2026 and more than 1,200 per cent since the AI training boom began in early 2024; Micron has gained roughly 190 per cent year-to-date and 1,300 per cent since April 2025.
The drivers are the same in both companies' filings: high-bandwidth memory, or HBM, the multi-layered stack of DRAM dies fused to a logic interposer that sits next to each of Nvidia's Hopper, Blackwell and forthcoming Vera Rubin GPUs. SK Hynix told investors at its first-quarter earnings call that its HBM3E and HBM4 capacity for 2026 was entirely sold out and that early order books for 2027 were "well advanced." Micron disclosed a similar position last week.
Nvidia, whose own valuation surged after its $81.6 billion first-quarter revenue print last week, has effectively become the single most important customer in the memory market. Bernstein estimates Nvidia will absorb fifty-eight per cent of all HBM units shipped in 2026, with Google, Meta and the three Chinese hyperscalers absorbing most of the rest. SK Hynix is the largest HBM supplier to Nvidia, with a roughly fifty-three per cent share, ahead of Micron and Samsung.
The rally has not been entirely smooth. SK Hynix and Micron both warned in recent filings that gross margins on HBM products have started to compress as Samsung and the Chinese maker CXMT push into the next generation. UBS analyst Timothy Arcuri, whose Tuesday note triggered Micron's 19 per cent surge, argued that pricing power would hold through 2027 because the cost of qualifying a new HBM supplier with Nvidia or Google was prohibitive.
South Korea's Kospi index closed up 2.1 per cent on Wednesday, with SK Hynix accounting for more than half of the index's gain. President Lee Jae-myung's office described the milestone as "a validation of South Korea's industrial strategy," and the finance ministry confirmed it would proceed with planned tax incentives for HBM-related capital expenditure announced in the spring supplementary budget. The win-Asia tilt of the memory trade has also accelerated capital flows back into Korean and Japanese equities, where foreign investors have been net buyers every session this month.