Western Digital's Guidance Gap: How a Beat-and-Raise Quarter Became a 20% Rout

Western Digital beats Q4 estimates but stock drops 20% on soft guidance and HAMR transition risks, highlighting AI-driven market expectations.

There's a peculiar arithmetic at work in markets right now: a company can deliver 44 percent revenue growth, crush earnings estimates by a wide margin, and still watch its stock get carved up like a disappointing earnings miss. Western Digital just provided the latest — and perhaps starkest — example of that dynamic.

The hard disk drive maker reported fiscal fourth-quarter results that, on their face, look like the stuff of a celebratory press release. Revenue came in at $3.75 billion, up 44 percent year over year. Adjusted earnings per share of $3.56 sailed past the analyst consensus of $3.29. GAAP net income reached $3.195 billion, helped along by a $2.05 billion one-time gain tied to the revaluation of Western Digital's remaining 19.9 percent stake in SanDisk. For the full fiscal year 2026, the company booked $12.92 billion in revenue.

None of that stopped the sell-off. The stock tumbled roughly 15 percent in premarket trading immediately after the print, then kept sliding. By Friday's close, the shares had shed another 4.28 percent, bringing the weekly loss to 20.50 percent. The damage from the June peak is even more striking: the stock now sits 46.06 percent below its 52-week high, reached just last month.

The Problem Isn't the Quarter — It's the Quarter After

The disconnect comes down to guidance. Western Digital projected first-quarter fiscal 2027 revenue of $4.0 billion to $4.2 billion — objectively another growth quarter, but apparently not the kind of blowout number that a market drunk on AI-driven storage demand had priced in. Evercore's Amit Daryanani had flagged the risk ahead of the report, warning that investor expectations were "clearly exaggerated." That warning proved prophetic.

The setup was always going to be treacherous. The stock had already climbed 144.09 percent since the start of the year, a rally that left little room for anything short of perfection. When the company delivered merely excellent results rather than transcendent ones, the air came out quickly.

Analysts Split on the HAMR Transition

The Street's response has been anything but uniform, which itself tells a story about how unsettled the debate over Western Digital's future has become.

Citigroup trimmed its price target on Friday from $800 to $740 but maintained its buy rating — a signal that the firm views the sell-off as overdone rather than deserved. Summit Insights took the opposite tack, downgrading the stock from "Buy" to "Hold" on Thursday, citing the risks embedded in the company's shift to HAMR, or heat-assisted magnetic recording, technology. That transition is the crux of the bull-bear argument: HAMR promises significantly higher storage densities, but it also introduces production complexity and execution risk that the older ePMR technology never carried.

Other firms staked out positions across a wide band on Thursday, with price targets ranging from $615 to $720. One house lifted its target dramatically, from $530 to $650. TD Cowen set its target at $540, Morgan Stanley at $676, and Robert W. Baird at $630. A quantitative model from Wall Street Zen went so far as to upgrade the stock to "Strong Buy" on Saturday. The dispersion in targets — from the mid-$500s to $800 — suggests the market has yet to converge on a consensus view of how the HAMR transition plays out.

A Divergence of Behavior Among the Faithful

Institutional behavior tells a more nuanced story. The Czech central bank increased its position by 6.3 percent during the second quarter, and a Japanese securities firm grew its — admittedly small — stake by more than fortyfold. Those moves suggest that at least some long-term investors see the pullback as an opportunity rather than a warning.

Meanwhile, director Martin Cole sold several thousand shares on July 29 under a pre-arranged trading plan, at prices ranging from $423.42 to $465.21. The sale is notable mainly for what it illustrates about the different time horizons at play — insiders with scheduled exits, institutions adding on weakness, and momentum traders heading for the exits all at once.

The Roadmap Ahead

Management, for its part, is sticking to a concrete timeline. CEO Irving Tan confirmed that the first 44-terabyte hard drives using HAMR technology are slated for delivery in the first half of calendar year 2027, while mass production of 40-terabyte drives using the current ePMR technology has already begun. The board also declared a quarterly dividend of $0.15 per share, payable September 17 to shareholders of record as of September 8.

The company plans to file its annual report for the fiscal year ended July 3 with the SEC on August 14, a filing that should provide additional color on the balance sheet and forward guidance. Media reports have also suggested Western Digital has revived merger talks with Japanese memory maker Kioxia, a deal that would pair its hard drive business with Kioxia's NAND production — a prospect that adds another layer of speculation to an already volatile story.

Since spinning off its flash memory business into the standalone SanDisk Corporation in February 2025, Western Digital has been a pure-play hard drive maker. SanDisk, for its part, reported $8.97 billion in quarterly revenue and announced a $14 billion share buyback program — a reminder that the two former siblings are charting very different courses.

The relative strength index has fallen to 37.6, a level that typically signals oversold conditions. That technical indicator, combined with the operational milestones management continues to hit, suggests the recent slide may have more to do with positioning and inflated expectations than with any deterioration in the underlying business. The HAMR execution risk is real, but it was equally real when the stock was trading 46 percent higher. What changed wasn't the company's prospects — it was the price investors were willing to pay for them.