HBM4 Era: Samsung and SK hynix Achieve 80% Yield Mass Production 

 As price growth for commodity DRAM looks set to moderate, the memory competition is shifting toward next-generation HBM, with Samsung, SK hynix and Micron accelerating their HBM4 ramp-up. Samsung has lifted its HBM4 yield to 80%, a sharp improvement from under 60% when mass production kicked off in February. Better performance of TC-NCF packaging and stable yields of underlying 1c DRAM fuel the progress. 

 The company targets HBM4 revenue to more than triple in Q3, with HBM4 accounting for over 60% of its total HBM sales in 2H26. Samsung aims to capture around 38% HBM market share by year-end, and expanded HBM4 supply will support volume production of NVIDIA’s upcoming Vera Rubin AI accelerator. On the other side, SK hynix also reaches roughly 80% HBM4 yield, backed by its proprietary MR-MUF packaging technology. 

The firm is ordering extra process equipment to lift HBM4 output. However, ongoing labor negotiation has become a critical variable: the union pushes back against management’s proposal to pay more than half of profit-sharing bonuses via treasury shares with lock-up restrictions. Any prolonged dispute may create risks for SK hynix’s capacity expansion, as Samsung quickly closes the gap. HBM supply will remain tight through 2027, keeping suppliers’ pricing power intact. 

HBM bit shipments are forecast to rise 50%–60% YoY in 2027, yet still fail to match surging demand. Market share landscape will be reshuffled: Samsung’s HBM4 share is projected to climb, while SK hynix may face pressure from qualification timelines and capacity competition, and Micron’s share stays relatively stable amid limited HBM4 exposure. The AI memory race is no longer only about technology maturity. 

Yield stability, capacity execution and supply chain risks such as labor relations will determine market winners in the HBM4 era.