SK hynix was first to announce HBM4 development completion and production readiness, but it was not the only supplier to reach the market. Samsung later claimed the first commercial HBM4 shipment, Micron reported volume shipments, and all three companies were publicly reported as qualified to supply NVIDIA’s Vera Rubin platform. SK hynix still has a strong HBM leadership case based on its overall market position and customer relationships, but “first HBM4” no longer describes an uncontested win.
What HBM4 is—and why AI companies need it
High Bandwidth Memory (HBM) is stacked DRAM designed to sit close to a processor, such as an AI accelerator. That placement and the memory’s wide interface let the processor move large amounts of data quickly. For AI training and inference, HBM helps keep data-intensive workloads supplied; memory capacity and bandwidth can otherwise constrain how effectively an accelerator is used.
HBM4 doubles the interface width to 2,048 I/O terminals, compared with 1,024 in the prior generation. A wider interface can raise aggregate bandwidth without relying solely on higher signaling speed per pin. SK hynix says its HBM4 exceeds 10Gbps per pin and delivers about twice the prior generation’s bandwidth. It also claims more than 40% better power efficiency than the previous generation. These are supplier-reported specifications and comparisons, not a common independent benchmark across vendors. SK hynix’s HBM4 announcement
HBM is difficult to scale because the product is more than a DRAM chip. Stacking, thermal management, integration with a logic base die, packaging, manufacturing yield and customer qualification all matter. Taller stacks can provide greater capacity, but add manufacturing and cooling challenges. Products from different suppliers may also vary in stack height, pin speed, base-die design and power characteristics, so “HBM4” does not mean every configuration is interchangeable.
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What SK hynix was first to do
In September 2025, SK hynix announced that it had completed HBM4 development and was readying what it described as the world’s first HBM4 mass production. That was a significant readiness milestone: it indicated the company had moved beyond an early concept or sample. It did not, by itself, establish that SK hynix shipped the first commercial product, won every customer qualification or held the largest share of HBM4 sales.
The milestones that followed show why “first” needs a qualifier:
- Development completion and production readiness: SK hynix announced these in September 2025.
- First commercial HBM4 shipment: Samsung claims this milestone in early 2026. Samsung’s announcement
- Volume shipments: Micron says its 36GB, 12-high HBM4 entered volume shipments in Q1 2026, designed for NVIDIA Vera Rubin. The statement does not establish that Micron shipped before Samsung under the same definition of “commercial shipment.” Micron’s investor materials
- NVIDIA platform qualification: In June 2026, NVIDIA CEO Jensen Huang was reported as confirming that Samsung, SK hynix and Micron had all passed HBM4 qualification for Vera Rubin. NVIDIA has not disclosed supplier allocations in the cited reporting. The qualification report
Qualification, commercial shipment and production readiness answer different questions. A sample can demonstrate technical progress; qualification indicates a customer has approved a product for a platform; and shipment or volume shipment concerns commercial supply. None alone reveals a supplier’s yield, total output, revenue share or customer allocation.
How the three suppliers compare
| Supplier | HBM4 status reported | Next-generation sampling | What the public evidence does not establish |
|---|---|---|---|
| SK hynix | Announced HBM4 development completion and mass-production readiness in September 2025; HBM4 performance and cost competitiveness meeting customer requirements were reported in its Q2 2026 results. | Announced 12-layer HBM4E samples on June 18, 2026, with speeds up to 16Gbps per pin. | Its HBM4 customer-by-customer allocations and comparable supplier yield figures are not stated in the cited sources. |
| Samsung | Claims the industry’s first commercial HBM4 shipment in early 2026. | Announced 12-layer HBM4E samples on May 29, 2026, with speeds up to 16Gbps per pin. | The shipment announcement does not establish that Samsung leads HBM4 volume, revenue, yield or NVIDIA allocation. |
| Micron | Reports Q1 2026 volume shipments of 36GB, 12-high HBM4 designed for NVIDIA Vera Rubin. | Reports sampling a 48GB, 16-high HBM4 product; this is a higher-capacity HBM4 configuration, not an HBM4E sample. | The cited materials do not provide a directly comparable supplier market share or NVIDIA allocation. |
Samsung’s HBM4E announcement also highlights its vertically integrated capabilities: advanced 10-nanometer-class DRAM, a Samsung Foundry 4nm logic base die, and memory, foundry and packaging operations within one corporate group. That may be strategically useful, but a sampling milestone does not prove it has overtaken SK hynix in HBM4 sales or production. Samsung’s HBM4E announcement
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Why SK hynix can still be the HBM leader
“Leadership” depends on the metric. A market-share estimate, first-shipment claim, platform qualification and technical specification measure different things. SK hynix has a strong case on overall HBM position and customer relationships, even though it does not own every HBM4 milestone.
- Established market position: A report citing market data put SK hynix at 61% of the overall global HBM market in 2025, compared with 21% for Micron and 17% for Samsung. These figures concern HBM overall, not HBM4 alone. Market-share report
- Forecast HBM4 share: Counterpoint estimates reported by Yonhap forecast SK hynix at about 54% of the global HBM4 market in 2026, Samsung at 28% and Micron at 18%. These are forecasts, not finalized audited results. Yonhap’s report
- Customer relationships: SK hynix said in its July 28, 2026 results that it had long-term agreements with approximately 10 key customers. The company did not publish customer-by-customer HBM4 allocations.
- Production and packaging experience: HBM requires repeatable stacking and packaging at scale, not just fast memory dies. SK hynix’s experience is a potential advantage, while its HBM4E packaging claims should not be mistaken for HBM4 specifications.
The market-share figures should not be combined into one ranking: one describes the reported 2025 overall HBM market, while the other is a 2026 HBM4 forecast. Neither discloses exact NVIDIA allocations. SK hynix and NVIDIA also announced a multiyear technology partnership to develop memory for AI factories. That is evidence of strategic cooperation, not an exclusive supply agreement or guaranteed share. NVIDIA and SK hynix partnership announcement
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why the HBM4 lead is not secure
Vera Rubin gives the supplier race immediate commercial importance: the platform needs high-performance HBM, and a three-supplier ecosystem can help NVIDIA reduce dependence on a single source. TrendForce expected Samsung, SK hynix and Micron to supply the platform, citing strong demand, constrained capacity and single-supplier risk. It also expected SK hynix to retain an allocation edge because of its established NVIDIA relationship, but that is an analyst view rather than a public NVIDIA allocation. TrendForce’s analysis
For suppliers, the challenge is to deliver qualified memory reliably in enough volume, at a workable cost and within a system’s power and thermal limits. A supplier can be ahead in development but lose commercial ground if it cannot scale yields or secure customer approval. Conversely, a first shipment does not show that the vendor has the largest output or best economics.
- Bandwidth versus power and heat: More data throughput is valuable only if the package can operate within the accelerator’s power and thermal limits.
- Capacity versus manufacturing difficulty: A 16-high stack can offer more memory per package than a 12-high stack, but greater stack height makes manufacturing and cooling harder.
- Early readiness versus mature production: Announcing readiness is not the same as proving sustained volume, yield and cost performance.
- Multiple suppliers versus uniformity: Diversification improves supply resilience, but different products and package characteristics can require system-level evaluation.
SK hynix’s Q2 2026 results reported revenue of 79.3187 trillion won and operating profit of 60.5426 trillion won, with a 76% operating margin, according to the company. Those results show the scale of the memory boom at that point; they do not guarantee future profitability. HBM capacity expansion demands investment, and memory economics remain exposed to supply, demand and pricing cycles. SK hynix’s Q2 2026 results
What HBM4E changes—and what it does not
HBM4E is a later generation, so its sampling milestones should be kept separate from HBM4 shipments. Samsung announced 12-layer HBM4E samples on May 29, 2026, and SK hynix announced its 12-layer samples on June 18. Both companies reported speeds up to 16Gbps per pin. Neither announcement establishes HBM4E mass production or commercial shipment.
SK hynix says its Advanced MR-MUF process reduced thermal resistance by 17% in its 12-layer HBM4E sample. That is a company claim about the HBM4E sample; it should not be applied to SK hynix HBM4 generally or treated as a head-to-head result. The close sampling dates show both companies advancing their roadmaps, not which will ultimately lead in production. SK hynix’s HBM4E announcement
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When a company or headline says it is first or leading, check what the statement actually measures:
- Development: Has the supplier completed its design, or is it showing an engineering sample?
- Production: Is it preparing for mass production, manufacturing at volume, or reporting stable output?
- Shipment: Does “shipment” mean a commercial shipment, volume shipments or samples sent for evaluation?
- Qualification: Which customer and platform has approved the product? Qualification for Vera Rubin does not establish qualification for every accelerator.
- Market position: Is the figure an audited result or a forecast, and does it refer to overall HBM, HBM4, volume, revenue or a particular customer?
- Performance: Are speed, bandwidth, power and thermal figures measured under comparable conditions and configurations?
HBM4 is not a retail memory upgrade for a desktop PC. It is supplied through semiconductor and platform qualification and enterprise procurement, typically as part of an accelerator package or AI system. Public unit pricing and supplier allocations are not stated in the cited sources.
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