Sell MU by Sep 27, 2026.

**TL;DR (Too Long; Didn't Read)** **The Core Premise:** Wall Street models HBM4/HBM5 market share using independent, additive yields. Physical 3D integration dictates that supply chain risks are **multiplicative, not additive**. **The Alliance Bottleneck:** The TSMC-Hynix/Micron alliance faces cross-border logistical latency (3-4 weeks TAT troubleshooting) and heterogeneous material warpage. Crucially, they are locked under a strict **60% maximum wafer allocation cap** from TSMC. **The Cruel Paradox:** In a severe HBM4 shortage, if baseline packaging yields drop, the Alliance cannot source extra …