Citi TMT $MU: "Overall, we believe the market is underestimating how constrained DRAM/HBM supply is likely to remain as AI-driven demand from hyperscalers continues to accelerate, while memory makers face diminishing benefits from process shrinks and must rely on long-cycle greenfield capacity additions. As a result, HBM and advanced memory supply could remain tight through 2027 and 2028." "Supply is the underappreciated piece, in our view: Node transitions yield less density (1-delta ~25% vs 1-gamma and prior nodes 30-40%). HBM's trade ratio eats wafer capacity, and DRAM bit growth is only in the low 20s. Real supply relief needs greenfield fabs, which takes a long time and cleanroom space is the constraint. Micron's construction spend as a % of capex is approaching 50%."