서부 데이터(Western Digital)는 1분기에 31억 9500만 달러를 벌어들였지만, 하드디스크 사업이 실제로 얼마를 벌었을까?

The profit margin on a hard drive has suddenly come to resemble that of an AI chip.

Western Digital, the U.S. storage company, reported revenue of $3.747 billion in its latest FY2026 Q4 earnings release. On a GAAP basis, earnings per share came in at $8.21. According to the company's announcement, the mark-to-market gain on its SanDisk stake was also included in the income statement.

This gives Western Digital's results two layers of interpretation. The first is the core HDD hard drive business after the flash memory spinoff, which sold more and became more profitable. The second is that its retained SanDisk stake fluctuated with market value, pushing GAAP profit to a level that isn't suitable for directly measuring the hard drive business.

This is not a one-quarter jump

Let's start with the most basic question. Is this growth confined to a single quarter?

According to Western Digital's FY2026 Q4 earnings release and its earlier Form 10-Q, the revenue trajectory from FY2025 Q4 to FY2026 Q4 shows no downward inflection point. It climbed steadily from $2.605 billion to $3.747 billion, with five actual quarters forming a continuous upward line.

The reason this line is worth viewing as a whole is that the accounting basis has changed. Western Digital completed the spinoff of its flash memory business in February 2025, and the independent SanDisk is no longer included in continuing operations. The latest earnings release also restated prior comparable periods on an HDD continuing operations basis. The growth in the chart is not the result of adding the SSD business back in, but rather a purer hard drive business expanding.

According to the company's earnings presentation on the same day, the cloud market accounted for 89% of Q4 revenue. This end-market label does not equate to AI revenue, but it shows that Western Digital's main revenue source is now hyperscale cloud providers and cloud service providers. Hard drives' role in this chain is not to provide computing power, but to provide large-capacity data storage.

According to the company's FY2026 Q4 earnings release, the midpoint of the FY2027 Q1 revenue guidance is $4.1 billion. For readers, the more important reminder than the solid line versus the dashed line is that guidance should only be treated as the company's current judgment, not as an established fact for the next quarter.

Selling more, and keeping more profit

Revenue growth does not automatically mean a better business. This is especially true in the hard drive industry—during an upcycle, shipments, pricing, inventory, and capacity utilization all squeeze into the income statement at once. What really matters is how much is left for every $100 of revenue.

According to the company's financials, GAAP gross margin reached 54.1% in FY2026 Q4. To put it more intuitively, for every $100 of storage products sold, more than half remains after deducting direct manufacturing costs.

Compared to a year ago, gross profit retained per $100 of revenue is roughly $13 higher. The other operating margin curve in the chart is also rising at a similar slope, indicating that R&D, selling, and administrative expenses have not swallowed up the incremental gross profit.

Here, the two lines cannot simply be attributed to one product or one customer. The earnings release itself only tells the market that cloud and other data-intensive workloads are expanding, and demand for Western Digital's products is increasing accordingly. It does not break out "AI" into an auditable revenue line item. What can be confirmed is that revenue growth and margin expansion occurred simultaneously over five quarters, and the incremental revenue clearly flowed through to operating margin.

Cash flow adds another layer of validation to this improvement. FY2026 Q4 free cash flow was $1.281 billion, and according to the company's earnings release, cash flow from operations was $1.389 billion. Hard drives remain a manufacturing business that requires equipment, materials, and inventory turnover. The fact that cash kept pace with profit provides another check on this quarter's operating results. It cannot by itself prove the trend will last forever, but it is closer to the money the enterprise can actually deploy than looking at the income statement alone.

Where does EPS actually come from

So why does GAAP earnings per share look more exaggerated than the improvement in the core business? The answer is in the last chart.

GAAP net income attributable to continuing operations for FY2026 Q4 was $3.195 billion. Under the company's defined Non-GAAP basis, that figure is $1.382 billion. The difference is not a miscalculation, but rather the company excluding certain items it does not intend to use for comparing routine operating performance from the latter.

The largest item is a $2.050 billion gain on the retained SanDisk stake. It comes from the mark-to-market revaluation of Western Digital's shares in SanDisk, not from revenue directly generated by selling more hard drives this quarter. The company also added back costs related to debt and equity transactions in the same reconciliation table, and made adjustments for taxes, stock-based compensation, and restructuring items.

This does not mean Non-GAAP is the only "real profit." It is still a comparable measure defined by the company and should be read alongside GAAP. Its value lies in separating changes in equity market value from the operating results generated by hard drive manufacturing and sales. If you only focus on the $8.21 figure, it is easy to treat two different types of gains as the same thing.

The most interesting part of Western Digital's earnings report is not that a hard drive suddenly has a chip-like valuation narrative, but that after the flash memory spinoff, both revenue and margins in the HDD core business have genuinely thickened together. The SanDisk stake makes GAAP profit look brighter, but once you peel it away, the remaining hard drive business is no longer what it was in the previous cycle.