SK Hynix is a South Korean semiconductor company and one of the world's two largest DRAM manufacturers. Its product portfolio includes conventional DRAM, NAND flash, and high-bandwidth memory (HBM)—the stacked DRAM product mounted directly on AI accelerators to provide the extreme memory bandwidth required for large-scale AI computation. SK Hynix has been the leading HBM supplier to Nvidia since the HBM3 generation and has maintained that position through HBM3E and into HBM4.

HBM is the memory architecture that enables modern AI accelerators to perform at their rated speeds. Nvidia's Blackwell B200 GPU is paired with 192 GB of HBM3E, and the bandwidth between GPU and memory is the primary bottleneck determining inference throughput for large language models. SK Hynix holds approximately 62% of the global HBM market as of Q2 2025. All HBM capacity across all three suppliers (SK, Micron, and Samsung) is sold out through 2026.

Annual revenue reached approximately $97T KRW ($65B) in 2025, with annual operating profit approximately $33B. SK Hynix is simultaneously shipping HBM3E for current Blackwell platforms and ramping HBM4 production for next-generation AI accelerators. HBM4 offers roughly double the bandwidth of HBM3E per stack.