On July 22, 2026 (UTC+8), the US stock market staged a robust rebound. All three major indexes closed higher, with the Nasdaq up 1.29%, the S&P 500 up 0.89%, and the Dow Jones up 0.74%. The Philadelphia Semiconductor Index stood out, surging 5.21% in a single day—its largest daily gain since June 22.
Within this rally, the storage chip sector led the charge. SanDisk jumped over 14%, SK Hynix rose more than 13%, Western Digital and Micron Technology both climbed over 12%, Seagate Technology gained more than 11%, and Kioxia ADR soared over 17%. Meanwhile, SpaceX ended a seven-day losing streak with a gain of more than 3%.
Why did the storage sector move in unison? The underlying driver is the systemic boost to the storage supply chain from expanding AI computing power. This article explores the layered structure of the AI industry and analyzes the investment logic behind the storage sector at this pivotal moment.
The Four-Tier Architecture of the AI Industry Chain and Storage’s Strategic Role
To understand the investment value of the storage sector, it’s essential to clarify its position within the AI industry chain.
Layer One: AI Chips. Nvidia and AMD are the core players at this level. AI model training and inference rely heavily on the parallel computing capabilities of GPUs, making chip performance the fundamental driver of AI application efficiency.
Layer Two: High-Speed Storage. This is the focal point of our analysis. AI chips require high-bandwidth, low-latency storage solutions to support rapid read/write operations for massive datasets. SK Hynix, Micron, and Samsung are the three global leaders in the HBM (High Bandwidth Memory) market.
Layer Three: Storage Devices. Beyond high-speed storage, AI data centers need large volumes of enterprise-grade SSDs and traditional hard drives to meet the demands for cold and warm data storage. Western Digital and Seagate are the key players in this segment.
Layer Four: Data Center Infrastructure. This includes server assembly, cooling systems, rack configurations, and power supply—essential components that provide the physical foundation for upper-layer hardware operations.
The storage sector spans both the second and third layers: HBM falls under high-speed storage, while enterprise SSDs and high-capacity mechanical hard drives are classified as storage devices. This "dual positioning" enables the storage industry to benefit from multiple facets of AI computing expansion.
HBM Market Dynamics: Competitive and Cooperative Strategies Among the Big Three
HBM is currently the fastest-growing segment in the storage chip industry. Compared to traditional DDR memory, HBM leverages 3D stacking technology to deliver higher bandwidth and lower power consumption, making it an indispensable component for AI accelerators like Nvidia’s H100 and B100 series.
In terms of market share, SK Hynix leads the HBM sector. The company was first to achieve mass production of HBM3 and maintains stable supply to key clients (notably Nvidia) with its HBM3E process. According to TrendForce, SK Hynix will hold about 48% of the global HBM market in 2025, followed by Samsung and Micron.
Samsung has adopted an aggressive approach to expanding HBM production capacity. In 2025, it announced plans to more than triple its packaging capacity compared to the previous year and accelerate HBM4 development. Samsung’s strength lies in vertical integration—controlling DRAM manufacturing, logic chip design, and advanced packaging—which gives it a unique edge in cost management.
Micron, the only US-based DRAM manufacturer, holds strategic value in supply chain security. Though its HBM production scale currently trails the two Korean giants, Micron began ramping up HBM3E shipments in the second half of 2025 and has entered Nvidia’s supply chain. From a valuation perspective, Micron is transitioning from a traditional DRAM/NAND cyclical stock to an AI growth stock, a process that is still underway.
Storage Devices: Structural Opportunities for Western Digital and Seagate
Beyond high-speed storage, the expansion of AI data centers is also fueling demand for enterprise storage devices.
Western Digital operates both HDD (hard disk drive) and NAND Flash product lines. In the HDD space, Western Digital and Seagate form a duopoly. As AI model parameters scale from hundreds of billions to trillions, total data volumes are rising exponentially. Ultra-high-capacity HDDs, with their cost advantage per unit of storage, remain irreplaceable for cold data storage.
Western Digital’s enterprise SSDs are also benefiting from increased AI workloads. Frequent checkpoint saving, data loading, and intermediate result caching during AI training require high-performance SSDs. In Q4 of fiscal year 2025, Western Digital’s enterprise SSD revenue grew over 70% year-over-year, outpacing its consumer business.
Seagate focuses exclusively on the HDD segment. Its heat-assisted magnetic recording (HAMR) platform has pushed single-drive capacity above 30TB, providing data center customers with a clear path for large-scale upgrades. In AI data lake architectures, high-capacity HDDs remain the most cost-effective choice for long-term storage of massive training datasets.
However, it’s important to note that the storage device sector is subject to the supply-demand cycles of NAND Flash and HDD. Since the second half of 2025, the NAND Flash market has experienced oversupply, with contract prices trending downward, which has put short-term pressure on Western Digital’s NAND margins.
Data Center Infrastructure: The Overlooked Source of Incremental Demand
AI data center construction drives not only chip and storage demand but also comprehensive expansion at the infrastructure level. Segments such as server PCBs (printed circuit boards), cooling modules, power management chips, and high-speed connectors are all benefiting from the AI capital expenditure cycle.
While this is not the main focus of our analysis, investors should closely monitor the capital expenditure guidance from major global cloud service providers (AWS, Microsoft Azure, Google Cloud, etc.) when assessing storage companies’ demand outlook. These giants’ procurement plans are the most important leading indicators for storage demand.
Risk Factors: Cyclical Concerns That Can’t Be Ignored
Despite the optimistic market sentiment, risks in the storage sector warrant careful attention.
First is inventory cycle risk. From the second half of 2025 through early 2026, certain storage chip categories (especially consumer-grade NAND) have shown rising inventory levels. If actual shipments of AI servers fall short of expectations, HBM could face similar oversupply pressures.
Second is geopolitical risk. Storage chip manufacturing is highly concentrated in East Asia (Korea, Japan, Taiwan). Any regional supply chain disruptions could impact global supply. The ongoing escalation of US export controls on semiconductors to China is also affecting storage companies’ market expansion.
Third is technology roadmap risk. HBM is not a static solution. With the development of in-memory computing and near-memory computing architectures, the boundary between storage and computation is blurring. If disruptive storage technologies emerge, current HBM capacity layouts may require revaluation.
Fourth is exchange rate risk. SK Hynix and Samsung incur costs in Korean won but earn revenue in US dollars, making their reported profits highly sensitive to currency fluctuations.
Conclusion: Clear Trend, Timing Is Key
The strong performance of the storage sector on July 22, 2026, essentially reaffirms the market’s confidence in the logic of expanding AI computing power. HBM, as a critical component for AI chips, has highly certain demand growth; enterprise storage devices are benefiting from ongoing data center expansion.
However, the cyclical nature of the storage industry means that short-term stock price fluctuations often exceed changes in fundamentals. Investors focused on the long-term growth prospects of Micron, SK Hynix, Western Digital, and similar companies must remain alert to NAND price cycles, inventory levels, and geopolitical factors.
Storage demand in the AI era is a long-term upward trend, but supply-demand mismatches will inevitably cause periodic volatility along the way.
FAQ
Q1: What is Micron’s position in the HBM market?
Micron is one of the world’s three major HBM suppliers. Its market share currently trails SK Hynix and Samsung, but it has entered Nvidia’s supply chain and achieved HBM3E shipments. As the only US-based DRAM manufacturer, Micron offers unique strategic value in supply chain security.
Q2: What is the main investment thesis for Western Digital?
Western Digital’s dual focus on enterprise SSDs and high-capacity HDDs enables it to meet both high-speed cache and cold storage needs in AI data centers. Additionally, merger talks with Kioxia regarding its NAND business present a potential catalyst.
Q3: How does the cyclical nature of storage chip prices affect investment?
Storage chip prices are highly cyclical, driven by supply and demand dynamics. When supply exceeds demand, average selling prices fall, squeezing profit margins; the reverse brings earnings flexibility. Currently, consumer-grade NAND is in oversupply, but HBM and enterprise products maintain strong demand.
Q4: What are SK Hynix’s core advantages over competitors?
SK Hynix was first to achieve large-scale HBM production and has established deep partnerships with Nvidia, giving it a lead in capacity and yield. The company is also expanding packaging capacity to strengthen its market position.
Q5: How large is the long-term growth potential for the AI storage sector?
Industry analysts project the global HBM market will reach tens of billions of dollars by 2027. Enterprise SSDs and high-capacity HDDs will also benefit from rising data volumes. In the long run, expanding AI workloads will continue to drive upgrades in storage hardware.
