SanDisk and Western Digital shares surged 6% on Friday as AI-driven demand for storage chips and hard drives propels both stocks to record highs, though traders remain divided on whether the rally reflects a multi-year boom or late-stage excess.

What happened

SanDisk stock rose 6% to near $1,989 and Western Digital climbed 6% to $561 on Friday. SanDisk has gained 724% year to date and 4,638% over the past 12 months; Western Digital is up 224% YTD and 902% over the past year, driven by surging AI infrastructure demand for memory chips and hard-disk drives.

Why it matters

SanDisk's Q3 FY2026 results delivered revenue of $5.95 billion（約9500億円） (up 251% year over year) and data-center segment revenue jumped 645% year over year to $1.47 billion（約2400億円）, while Western Digital reported revenue of $3.34 billion（約5300億円） (up 46% year over year) and non-GAAP gross margin cleared 50% for the first time in recent memory. Both companies have guided for strong Q4 results, suggesting sustained momentum from AI workloads that create persistent data storage needs.

What to watch

SanDisk has locked in approximately $42 billion（約6.7兆円） in multi-year supply agreements, and Susquehanna carries a $2,000 price target on SNDK stock, the highest on the Street. However, insider selling has surfaced—a director offloaded 579 shares near $1,503 in early May—and bearish sentiment on social media suggests the move may be overextended. Incoming NAND and hard-disk drive pricing data will be the key signal for whether the rally is sustainable.