The S&P 500 slipped on September 4 as a stronger jobs report revived rate concerns, yet four AI-linked memory and storage stocks moved sharply higher. Sandisk, Micron, Seagate and Western Digital all rallied as investors rotated toward the hardware feeding AI data demand.
The S&P 500 fell 0.4% on September 4 after a stronger-than-expected jobs report lifted rate concerns. Even so, Sandisk jumped 11.9%. Micron gained 6.1% the same day. Seagate rose 6.3%. Western Digital added 5.9%. The divergence was not a broad risk-on move; instead, it was consistent with investors rotating toward memory and storage suppliers that keep AI systems fed with data.
Memory stocks power the split
Sandisk's August results established data center demand as a growth pillar, and management said it had signed five more new-business-model agreements since April. Micron, which supplies high-bandwidth memory alongside conventional DRAM and NAND, posted fiscal third-quarter revenue of $41.46 billion. Within that, Cloud Memory revenue reached $13.77 billion and Core Data Center revenue reached $11.52 billion. Still, extraordinary margins invite capacity additions, and today's scarcity economics may normalize faster than investors expect.
Storage names catch the same bid
Seagate, the mass-capacity hard-drive specialist, attributed its performance to robust cloud data-center demand, arguing that AI-driven data creation should support durable demand for high-capacity storage. Western Digital's appeal is similar after the Sandisk separation simplified its structure, but a few cloud buyers can shift purchasing schedules quickly, which is the shared risk behind both stocks.
Hedge funds built positions ahead of the rally
Insider Monkey's filings database counted 128 hedge funds holding Sandisk at June 30, up from 114 at March 31. Hedge-fund breadth in Micron rose to 184 funds in Q2 from 154 in Q1. Seagate's holder count climbed to 131 funds at June 30 from 93 at March 31. Western Digital ownership rose to 98 funds in Q2 from 83 in Q1. Those filings are quarter-end snapshots and do not show what the funds did during the September move.
Short interest tells a mixed story
An August 14 settlement recorded 7,676,558 Sandisk shares sold short, about 8.24% of the estimated public float, equal to roughly half a day of average trading volume. Seagate's same-date settlement showed 8,161,824 shares sold short, about 3.6% of shares outstanding and 1.72 days to cover. That modest ratio offers little evidence Friday's gain was a short squeeze; the stronger interpretation is a rotation toward profitable infrastructure. The next proof points for all four stocks are pricing, data-center mix, and whether customer commitments survive the next supply response.
Sources: Insider Monkey via Yahoo Finance, Insider Monkey via Yahoo Finance
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