On July 28, 2026, Seagate Technology announced that revenue for fiscal Q4 2026 rose 48% year-over-year to $3.629 billion, with non-GAAP gross margin reaching a record 52.7%. This level of profitability is unusual for an HDD maker, and the company expects non-GAAP operating margin to climb to roughly 50% in the coming quarter. According to Seagate, AI-embedded applications are expanding both data generation and retention periods, while cloud providers are locking in HDD supply over the long term. By combining HAMR—which increases areal density—with pricing and supply discipline, the company has begun changing how HDDs generate profit.
What a 52.7% Gross Margin Reveals Beyond Revenue Growth
GAAP gross margin for Q4 came in at 52.3%, up 14.9 percentage points from 37.4% a year earlier. On a non-GAAP basis, margin rose 14.8 points from 37.9% to 52.7%, up 5.7 points sequentially. While revenue grew 17% quarter-over-quarter, non-GAAP operating expenses actually declined 1%, from $296 million to $293 million. Having absorbed revenue growth with almost no increase in operating expenses, the company achieved a non-GAAP operating margin of 44.6% and net income of $1.319 billion.
This growth cannot be explained away by differences in the number of days in the quarter. Seagate's fiscal 2026 spanned 53 weeks, but the extra week fell within Q1, meaning Q4 was 13 weeks long—the same length as the year-ago quarter. While the calendar difference contributes slightly to the 34% full-year revenue growth, the 48% growth in Q4 compares periods of identical length.
The revenue breakdown narrows down the reasons behind the improved profitability even further. Data center revenue rose 57% year-over-year to $2.933 billion, accounting for 81% of total revenue. Data center exabyte shipments grew 43% to 195EB—meaning revenue grew faster than shipped capacity. Because this figure includes product mix and system sales, the ratio between the two cannot be directly interpreted as the average selling price per HDD. Even so, revenue clearly outpaced exabyte growth.
In the prior quarter's earnings call, Seagate had explained that long-term pricing strategy and product mix were driving gross margin improvement, with data center revenue per terabyte rising in the mid-single digits year-over-year. This quarter again saw revenue outgrow shipped capacity, pushing non-GAAP gross margin even higher. The data disclosed so far is most consistent with the idea that three forces—pricing, product mix, and falling costs for high-capacity products—have continued to work together.
Nearline HDD Supply Allocated Through 2028
In Q4, Seagate shipped 218EB of HDD capacity in total, roughly 90% of which went to data centers. Nearline HDDs—used by cloud providers and large enterprises for massive data storage—reached 195EB, up 43% year-over-year. In contrast, non-nearline products declined 10% to 23EB. Seagate explains that AI-embedded applications are accelerating data generation, extending retention periods, and increasing the use of historical datasets in advanced inference workloads. The center of growth has clearly shifted toward high-capacity drives.
The supply-demand timeline stretches even further out. According to Seagate, nearline HDD supply allocations are largely filled through 2028, and customers are already beginning discussions about procurement plans for 2029 and beyond. This is not an audited backlog, nor does it mean all volumes and prices have been finalized. Still, it indicates that cloud providers are seeking to secure capacity over multiple years rather than through spot purchases a few quarters out. This gives manufacturers clearer visibility into demand and reduces the need to cut prices to protect factory utilization.
Rival Western Digital faces the same pressures. In its fiscal Q3 2026, revenue rose 45% and non-GAAP gross margin reached 50.5%. The company expects Q4 margin to reach 51–52%. While Seagate's proprietary HAMR technology creates a differentiator, the fact that both companies have crossed into the 50% range suggests that pricing discipline and tight supply are lifting the entire HDD industry.
That said, even as nearline supply fills up, retail external HDDs won't disappear overnight. Seagate's Edge & IoT revenue rose 20% to $697 million, showing that the non-nearline market operates under different supply-demand dynamics. For now, the impact is showing up primarily as manufacturing resources and new technology get prioritized for cloud customers, where they generate the highest value.
Why the 44TB Mozaic 4+ Boosts Profitability
The Mozaic 4+ uses Heat-Assisted Magnetic Recording (HAMR) to increase areal density, packing in up to 44TB. Seagate completed qualification with two major global cloud providers by March 2026 and began mass shipments. According to Q4 materials, both customers are now ramping production, and qualification work continues with other customers as well.
For manufacturers, the advantage lies in increasing capacity without adding more components to each drive. Seagate explains that Mozaic 4+ delivers more than 30% more capacity than the first-generation Mozaic using the same number of disks and heads, with minimal changes to components. Even with flat unit shipments, the number of exabytes shipped from the factory increases. This is precisely why, in the prior quarter's earnings call, management cited falling costs for 40TB products, pricing, and product mix as factors behind margin improvement.
There are economic benefits for customers as well. According to Seagate's internal estimates, compared to building 1EB using 30TB products, Mozaic 4+ improves infrastructure efficiency by approximately 47%, reducing floor space by about 100 square feet and annual power consumption by roughly 800,000 kWh. Fewer drives mean less enclosure, rack, cooling, and replacement work. If manufacturers can reflect the value of higher density in pricing while also lowering customers' total cost of ownership, both sides can share in the benefits of increased density.
That said, HAMR is not a technology that generates profit unconditionally. Seagate notes that its manufacturing cycle is somewhat longer than that of conventional perpendicular magnetic recording, meaning yield improvements and customer qualification will determine the pace of production ramp-up. Capital expenditure for fiscal 2026 doubled to $569 million from $265 million the previous year. While this remains within about 4.7% of revenue, achieving higher density requires upfront investment. Qualification shipments for the next-generation Mozaic 5+ are also scheduled for late 2027, meaning the transition to 50TB-class drives is still some time away.
Western Digital has chosen a different path. Its 40TB UltraSMR ePMR product is currently undergoing qualification with two cloud providers, with mass production planned for the second half of 2026, while full-scale HAMR production is slated to begin in 2027. Seagate moved first into mass production with its 44TB HAMR drive, but its rival intends to narrow the capacity gap by extending existing technology. To keep converting technological advantage into profit, Seagate will need to advance Mozaic 4+ production ramp-up and yield improvements faster than the pace of mass production from the ePMR camp.
Three Numbers That Confirm the 50% Operating Margin
The rise in profitability has also translated into cash. Q4 operating cash flow was $1.305 billion, and free cash flow—after subtracting capital expenditure—was $1.118 billion. Over the course of fiscal 2026, the company reduced total debt by $1.4 billion, bringing net debt at fiscal year-end down to $1.899 billion and net leverage ratio down to 0.4x. The fact that Seagate managed to reduce financial burden while increasing capital investment in HAMR supports the view that this quarter's profits are more than just an accounting figure.
For fiscal Q1 2027, Seagate expects revenue of $4.1 billion, plus or minus $100 million, non-GAAP operating margin of approximately 50%, and non-GAAP diluted EPS of $7.30, plus or minus $0.20. The midpoint of the revenue guidance represents a 13% increase from this quarter, while non-GAAP operating expenses are expected to remain roughly flat at about $300 million. The setup is designed so that, as long as supply allocation, pricing, and increased density all align, most of the revenue growth flows straight into operating profit.
Three numbers will determine whether this is sustainable: how much further nearline exabyte shipments grow beyond 195EB, whether Mozaic 4+ becomes the core of HAMR shipments, and whether the company can actually sustain a 50% operating margin. The strength of demand is already visible in the 2028 allocation status. What Seagate must now prove is whether it can meet that demand through areal density rather than unit volume growth—and carry its current profitability forward into the next generation of products.