Micron ramps up HBM capacity at Taiwan's four major sites

Micron's simultaneous HBM expansion across four sites in Taiwan, China is not a capacity story—it is a structural repricing of the memory layer in the AI compute arms race. Technically, HBM's bottleneck sits in TSV stacking and hybrid bonding yield, not DRAM die output. The four-site dispersion is a geographic redundancy hedge against yield variability, contrasting sharply with SK Hynix's concentrated bet on Cheongju. The projection that 2027-28 supply tightens further signals HBM4's migration beyond 12 layers will make thermal management the binding constraint—scaling die capacity will not linearly translate into usable HBM. On compliance, anchoring HBM's primary production in Taiwan, China rather than the US is a deliberate trade-off: commercial efficiency over CHIPS Act compliance costs. Yet it embeds a geopolitical exposure no diversification fully neutralizes. Competitively, Samsung will likely accelerate HBM4E mass production to seize the window, while SK Hynix locks long-term contracts with NVIDIA's next-gen platforms. If Micron cannot push HBM share past 30% by 2027, it faces a "capacity without certification" trap—customer qualification cycles run 12-18 months. 18-month outlook: HBM pricing power shifts from seller's market to technology-generation differentiation. First-to-ship HBM4E captures excess margin; laggards enter price wars. Memory is transitioning from cyclical to AI-infrastructure logic. This inventory bottom will be shallower and shorter than consensus expects.