SanDisk RSI Tops 99 Amid Debate Over AI-Driven Rally

SanDisk’s monthly Relative Strength Index rose above 99, a level analyst Lark Davis described as unprecedented for a publicly traded stock. The shares have gained roughly 780% year-to-date in 2026 and more than 5,400% since the company separated from Western Digital in February 2025. The stock traded near $2,138, up from an IPO price of about $38.50.

SanDisk became a pure-play maker of NAND flash memory and solid-state drives after the spinoff. Demand from hyperscalers investing in artificial intelligence infrastructure has supported multi-quarter growth in enterprise SSD orders. The company reported revenue growth of 251% year-over-year in its most recent quarter.

The Relative Strength Index is a momentum indicator that runs on a 0-to-100 scale. Readings above 70 commonly indicate overbought conditions; a monthly reading above 99 places SanDisk well beyond typical technical thresholds and signals sustained buying pressure that many models do not reliably interpret.

Market participants are divided over the rally’s cause. Some investors draw parallels with past episodes where rapid price gains preceded sharp pullbacks. Investor Ray Dalio has warned that strains on liquidity tied to AI investment could prompt some holders to sell positions to meet funding needs. Other investors point to ongoing demand for high-density, fast-access storage used in AI training and inference workloads as the driver of sales.

Analysts and traders note precedents earlier in 2026 when other technology names exceeded standard overbought readings before momentum cooled. One stock that rose more than 5,100% later gave back about 35% of its gains, a development market watchers cite when assessing potential volatility after large rallies.

Whether SanDisk’s advance continues will depend on hyperscaler capital expenditure plans through the second half of 2026 and on enterprise adoption of higher-density storage for AI applications. The record RSI has prompted some technical traders to consider profit-taking and has increased scrutiny from analysts tracking the durability of hyperscaler commitments.

SanDisk’s shift from a diversified unit inside Western Digital to a focused NAND and SSD company has coincided with stronger industry spending on AI infrastructure. The company’s recent financial results show rapid top-line growth tied to that shift, and the extreme technical reading has placed SNDK under close observation by both momentum traders and fundamental analysts.