Western Digital, Micron, Sandisk hover at all-time highs as AI trade reignites

The memory sector is trading at or near all-time highs as AI infrastructure buildout — particularly HBM and enterprise SSD demand — re-energizes the group. Micron (MU) and Western Digital (WDC) each posted ~50% YoY revenue growth in their most recent fiscal years with gross margins near 40%, signaling a genuine upcycle rather than a dead-cat bounce. Sandisk (SNDK), recently spun off from WDC, grew revenue only 10% YoY and is running a -22% net margin and -$11.32 diluted EPS, suggesting it remains in a restructuring/cost-absorption phase.

The setup is a classic upcycle-at-highs tension: MU and WDC have the revenue and margin momentum to justify elevated multiples if AI capex holds, but buying at all-time highs leaves little cushion for any demand-softening signal or inventory build. SNDK is the wildcard — if its cost structure normalizes post-spinoff, it could re-rate sharply, but the negative EPS makes it speculative. Watch for MU's next earnings print and any hyperscaler capex commentary as the key near-term catalysts.