SK Hynix is a South Korean memory chipmaker and one of the two largest members of the KOSPI index. Together with Samsung Electronics and Micron of America it rakes in more than 90% of global DRAM revenue. All three are switching capacity to high-bandwidth memory (HBM), a specialised variant that stacks chips vertically for use in AI processors. HBM requires three to four times as many silicon wafers as standard DRAM but yields operating margins of 50% or more, compared with 35% for standard memory. HBM will account for half of global DRAM revenue by the end of the decade, up from 8% in 2023, according to Bloomberg Intelligence. The shift to HBM has made basic memory chips scarcer and costlier: the price of DDR4, the DRAM found in most consumer electronics, rose by 1,360% between April 2025 and January 2026. As part of its contribution to the Yongin mega-cluster, SK Hynix is building a "mini-fab", a chip factory where smaller tool and materials firms can test their products.
All three big HBM producers say that most of their supply for 2026 is sold out. Demand for HBM is expected to outstrip supply for at least the next three years.
Its shares rose by more than 220% in 2025 amid an AI-fuelled memory shortage—a gain in line with that of Micron, its Idaho-based rival. SK Hynix is considerably cheaper than Micron, however: it trades at about eight times expected earnings, against 13 times for Micron. On December 10th 2025 SK Hynix announced it was considering listing in America, presumably to take advantage of higher valuations. The long-standing "Korea discount"—reflecting investors' concerns about poor corporate governance and unwieldy conglomerates—weighs on the valuation of South Korean stocks, which trade at a pitiful 1.4 times book value.
When all else failed, she tried being reasonable.