WDC’s better-than-expected results reinforce the positive HDD cycle view, with TDK as the top pick

Overview

The report evaluates the impact on Japan’s electronic components and HDD components supply chain based on Western Digital’s fiscal 4Q26 results and management outlook. WDC’s revenue, gross margin, and next-quarter guidance all exceeded market expectations, reflecting strong nearline HDD demand, higher selling prices per TB, an increased mix of high-capacity products, and improved manufacturing efficiency. JPMorgan believes industry capacity growth is coming more from increases in capacity per drive rather than expansion in the number of HDD units, meaning general HDD component makers may not necessarily benefit from unit growth; however, TDK may gain market share due to changes in the magnetic head supply structure during the HAMR migration.

Core views

First, cloud nearline HDD remains the core growth driver, with AI demand expanding from training to inference, agentic AI, and physical AI, providing potential incremental demand in 2027 and beyond. Second, stable pricing, an optimized mix of high-capacity HDDs, and lower unit costs are jointly driving margins higher. Third, WDC can expand shipped capacity without increasing HDD unit capacity, implying that supply-chain opportunities are more tilted toward technology upgrades and share shifts rather than traditional unit expansion. Fourth, HDD manufacturers’ constraints on magnetic head capacity expansion and the shift of existing capacity toward HAMR are favorable for TDK to gain magnetic head market share, making TDK the report’s top HDD-related pick.

Analysis framework

The report uses methods including comparison of results and guidance versus expectations, volume-price-cost decomposition, end-market structure analysis, product technology roadmap tracking, and supply-chain mapping. Specifically, it compares WDC’s actual data with company guidance and Bloomberg consensus, and derives the potential impact on Japanese HDD component suppliers from dimensions such as shipped capacity, price per GB, cost per TB, long-term customer agreements, and the pace of ePMR and HAMR adoption.

Methodology notes

• Earnings analysisComparison of actual results with guidance and consensus expectations

  Beat analysis

  Compares WDC’s quarterly revenue and gross margin with the midpoint of company guidance and Bloomberg consensus, and combines next-quarter guidance to assess the sustainability of the cycle.

• Operating decompositionVolume-price-cost analysis

  Shipped capacity, pricing, product mix, and unit cost

  Breaks down profitability improvement into nearline HDD shipped capacity growth, higher price per GB, increased mix of high-capacity products, improved manufacturing efficiency, and lower cost per TB.

• Industry researchSupply-chain mapping

  Transmission from HDD manufacturer performance to component suppliers

  Uses WDC’s demand, capital expenditure, and technology migration information to assess the impact on volumes, share, and profitability for Japanese HDD magnetic head and related electronic component companies.

• Technology roadmapTracking of ePMR and HAMR adoption

  Storage density upgrade

  Tracks the mass production, qualification, and customer adoption pace of next-generation 40TB ePMR, 44TB HAMR, Ultra SMR, and high-bandwidth HDDs, assessing the cost and supply-chain changes brought by product upgrades.

Asset mapping & comparison

Structured mapping from thesis to named assets (strengths, weaknesses, peers, risks).

• TDK (6762.T)

  Japanese HDD magnetic head supplier and the report’s top HDD-related stock pick

  Strengths

  Expected to benefit from HDD manufacturers limiting new magnetic head capacity, the migration of existing capacity toward HAMR, and increased share for external suppliers; OW rating maintained.

  Weaknesses

  Industry capacity growth is mainly driven by increases in capacity per drive, with limited growth in HDD units, so traditional shipment volume elasticity may be weaker than headline data suggest.

  Comparison

  Compared with general HDD component makers, TDK’s investment thesis relies more on changes in magnetic head market share and the HAMR technology migration rather than HDD unit growth.

  Risks

  Delays in HAMR adoption, weaker-than-expected customer qualification, changes in HDD manufacturers’ in-house magnetic head strategies, or weakening HDD demand could all undermine the share-gain thesis.

• Western Digital Corp (WDC)

  Global HDD manufacturer whose results and outlook are a key leading indicator for assessing the cycle of Japan’s electronic components supply chain

  Strengths

  Strong nearline HDD demand, favorable pricing environment, improved high-capacity product mix, lower cost per TB, and long-term agreement discussions extending to 2029–2031.

  Weaknesses

  The cloud business accounts for 89% of revenue, indicating concentrated customer and end-market exposure; inventory value and days of inventory increased QoQ.

  Comparison

  WDC directly benefits from improvements in capacity, pricing, and costs, while the degree of benefit for Japanese component suppliers depends on component value content, technology upgrades, and market share changes.

  Risks

  A slowdown in cloud capital expenditure, price declines, delays in technology mass production or customer qualification, and weaker-than-expected ramp-up of high-capacity products.

Key data

• WDC fiscal 4Q26 revenueUS$3.75 billionUp 44% YoY and 12% QoQ; above the company guidance midpoint of US$3.65 billion and consensus expectation of US$3.68 billion.
• WDC fiscal 4Q26 non-GAAP gross margin54.4%Up 13.0 percentage points YoY and 3.9 percentage points QoQ; above the guidance midpoint of 51.5% and consensus expectation of 51.9%.
• WDC fiscal 1Q27 revenue guidanceUS$4.10 billionGuidance midpoint, up 46% YoY and 9% QoQ; above consensus expectation of US$4.03 billion.
• WDC fiscal 1Q27 gross margin guidance55.5%Guidance midpoint, up 1.1 percentage points QoQ; above consensus expectation of 54.2%.
• Total HDD shipped capacity231EBUp 22% YoY and 4% QoQ.
• Nearline HDD shipped capacity209EBUp 23% YoY and 5% QoQ, the main source of capacity growth.
• Cloud business revenueUS$3.34 billionUp 43% YoY and 12% QoQ, accounting for 89% of total revenue.
• Price per GB1.6 centsUp 18% YoY and 8% QoQ, with pricing improvement having expanded to the client and consumer markets.
• Change in cost per TBDown 8% YoYWDC expects cost per TB to decline by about 10% annually over the medium to long term, driven by high-capacity HDDs and areal density improvements.
• InventoryUS$1.51 billionUp US$150 million QoQ; days of inventory were approximately 77 days, up 2 days QoQ.
• TDK rating and share priceOW; ¥3,013Price as of the close on August 6, 2026; the report identifies TDK as the top pick among HDD-related stocks.
• TDK reference target price¥5,500The latest disclosed target price implies potential upside of approximately 82.5% relative to the current price.

Impact & implications

WDC’s data indicate that the growth driver for the HDD industry is shifting from HDD unit expansion to improvements in capacity per drive, product mix, and pricing. This structure provides limited volume pull for ordinary component makers but increases the value content and supply importance of key technology components. As HDD manufacturers shift existing magnetic head capacity toward HAMR while restraining new capacity additions, TDK may gain opportunities to increase its magnetic head share. Meanwhile, the adoption of ePMR, HAMR, Ultra SMR, and high-bandwidth HDDs will become key catalysts for Japan’s electronic components supply chain over the coming quarters.

Risks

• HDD shipped capacity growth is mainly coming from increased capacity per drive rather than HDD unit growth, so volume elasticity for general component makers may be limited.
• The cloud business accounts for 89% of WDC’s revenue; if capital expenditure or nearline HDD orders from major cloud customers slow, results could come under significant pressure.
• If the favorable pricing environment reverses due to changes in supply-demand dynamics or a decline in NAND prices, gross margin improvement may be slower than expected.
• Mass production or customer qualification of 44TB HAMR, next-generation ePMR, Ultra SMR, and high-bandwidth HDDs may be delayed.
• TDK’s share gains depend on HDD manufacturers limiting in-house magnetic head capacity and advancing the HAMR migration; changes to these strategies would weaken the investment thesis.
• WDC’s inventory rose to US$1.51 billion and days of inventory increased QoQ, requiring attention to subsequent inventory digestion and demand matching.

What to watch

• Whether WDC’s fiscal 1Q27 revenue and gross margin can meet or exceed the guidance midpoint.
• Quarterly changes in nearline HDD shipped capacity, price per GB, and cost per TB.
• Negotiations for long-term agreements covering 2029–2031 and the scope of customer coverage.
• The full launch of next-generation 40TB ePMR over the coming quarters and its share of nearline HDD shipments.
• Progress in the start of 44TB HAMR shipments in the first half of 2027 and customer qualification results.
• Progress toward the target for Ultra SMR to account for approximately 60% of nearline HDD shipped capacity by the end of fiscal 2027.
• TDK’s share changes in the HDD magnetic head market and HAMR-related capacity allocation.
• The actual storage demand pull from AI demand expanding from training to inference, agentic AI, and physical AI.