Why is SK Hynix’s stock price setting new highs again?
HBM4E delivered to major customers, leading the AI memory chip competition

June 18, 2026, South Korean memory chip giant SK Hynix announced it had delivered 12-layer HBM4E samples to major customers, with the stock price rising intraday by 5.6% to 2.64M won, hitting a new all-time high. The closing increase further expanded to over 7%, at 2.71M won. As a result, SK Hynix's year-to-date increase has exceeded 300%.

This is not an ordinary sample delivery. Against the backdrop of exponential growth in AI computing power demand, HBM (High Bandwidth Memory) has leapt from a segment of DRAM to a "strategic resource" that determines the performance ceiling of AI chips. The delivery of HBM4E samples marks the full-scale launch of customer validation and mass production competition for the next-generation AI memory.

Why HBM4E Sample Delivery Can Drive Stock Prices to Record Highs

The capital market's reaction to HBM4E sample delivery was extremely swift and intense. After SK Hynix's stock price surged 24.2% over five consecutive days, it again jumped 5.6% in the early trading session on June 18, setting a new intraday record high. The Korea Composite Stock Price Index (KOSPI) broke through 9,000 points for the first time on the same day, with SK Hynix becoming the most important driver of this rally.

The significantly earlier-than-expected sample delivery was the direct catalyst for the stock price explosion. Industry insiders previously expected SK Hynix might not send HBM4E samples to customers until July, but the actual progress was about a month ahead. In the AI computing arms race, the "time gap" itself is a competitive advantage—being first to deliver samples means entering customer validation processes first and locking in memory supply shares for the next-generation AI accelerators.

Deeper driving forces lie in the structural imbalance of supply and demand in the HBM market. According to SEMI China data, the HBM market size is expected to grow 58% in 2026 to $54.6 billion, accounting for nearly 40% of the DRAM market. However, even with the three major manufacturers—Samsung, SK Hynix, and Micron—shifting 70% of their new capacity to HBM, the capacity gap still reaches 50% to 60%. Goldman Sachs and other institutions estimate that the structural shortage of HBM supply will persist at least until 2028. All of the HBM capacity for the three memory giants in 2026 has been sold out to customers, with core clients even locking in capacity through 2028.

In such a tight supply landscape, any positive signals regarding the advancement of next-generation products are amplified and interpreted by the market. Daiwa Securities sharply raised SK Hynix's target price to 3.6 million won in mid-June, reaffirming a "Buy" rating.

How AI Computing Expansion Reshapes the Supply-Demand Logic of High-End Storage Chips

To understand the industry significance of HBM4E sample delivery, one must first understand HBM's position in the AI computing chain. HBM uses 3D stacking technology to vertically integrate multiple DRAM chips, providing high-bandwidth data channels for AI accelerators. The exponential growth in memory bandwidth and capacity demands from large model training and generative AI inference directly determines the efficiency of AI training and inference.

The tight supply and demand of HBM are not simply due to "demand exceeding supply," but result from a series of structural factors. First, HBM production involves complex TSV (Through Silicon Via) and advanced packaging processes, with capacity expansion inherently delayed. Second, the three major manufacturers have shifted large portions of their DRAM capacity to HBM, which exacerbates the contraction of traditional DRAM supply, creating a chain reaction of "HBM overexpansion and overall DRAM shortage."

TrendForce estimates that by the end of 2027, the silicon wafer input for HBM from the three suppliers will account for 30% of total DRAM wafer input, further intensifying the squeeze on total DRAM capacity. UBS believes the recovery cycle for DRAM products will last until Q2 2028.

In this context, the advancement of HBM4E is not just a technological iteration but also crucial to the supply capacity of the entire AI infrastructure. HBM4E is expected to be integrated into NVIDIA's Rubin Ultra platform planned for 2027, with its mass production schedule directly impacting the shipment pace of next-generation AI accelerators.

From HBM3 to HBM4E: The Technical Logic of Memory Generation Leap

HBM4E is the seventh-generation high-bandwidth memory product, with a comprehensive upgrade over HBM4. According to technical parameters, the 12-layer stacked HBM4E sample achieves several key breakthroughs:

Bandwidth and Speed: The pin rate can reach up to 16 Gbps, with per-stack bandwidth up to 4.0 TB/s. Compared to HBM4, HBM4E offers approximately 38% higher bandwidth and a 33% increase in single Die capacity.

Capacity: Achieved through 12-layer stacking, reaching 48 GB of storage.

Power Efficiency: Improved by over 20%, significantly enhancing data processing capabilities needed for AI training and inference.

Thermal Management: Uses advanced MR-MUF (Mass Reflow Molded Bottom Fill) process, reducing thermal resistance by about 17% compared to HBM4, ensuring stable operation in high-performance computing environments.

From HBM3 to HBM3E, then HBM4 and HBM4E, each generation's iteration cycle shortens, while performance improvements accelerate. This trend reflects the "push" of AI computing power demands on memory performance—when GPU computing power doubles every two years, memory bandwidth must also increase in tandem to avoid becoming system bottlenecks.

After Samsung's Lead Sample Delivery: The "Three Kingdoms" Stage in the HBM Race Enters a New Phase

The high attention to HBM4E sample delivery is also due to its direct impact on the competitive landscape of the HBM market. SK Hynix's sample delivery was only about three weeks after Samsung Electronics announced the delivery of its first HBM4E samples. On May 29, Samsung began delivering its first HBM4E samples globally, claiming to be the world's first shipment.

The timing gap between the two Korean giants is very close—Samsung is about three weeks ahead, but SK Hynix's actual sample delivery was also earlier than market expectations. This "chase" rhythm means the customer certification window for HBM4E has fully opened. Whoever can be the first to pass validation with major clients and lock in mass production orders will gain a competitive advantage in the next round of AI memory supply.

In terms of market share, SK Hynix remains the leader. According to Counterpoint Research, in Q1 2026, SK Hynix held about 58% of the global HBM market, with Samsung and Micron each holding around 21%. Visible Alpha's data shows SK Hynix's share at approximately 55.5%, Samsung at 23.3%, and Micron at 21.2%. Despite differences in data sources, SK Hynix's leading position is clear.

However, competition is accelerating. TrendForce projects SK Hynix's HBM market share could shrink from 59% to about 50% in 2026, with Samsung's share rising. Micron plans to start mass production of HBM4E standard products next year, adopting the first EUV lithography process with 1γ technology. The three companies' HBM4E products are gradually entering customer validation windows.

SK Hynix's main clients include NVIDIA, AMD, and Google—major global AI giants. Its deep cooperation with NVIDIA is a core competitive advantage—NVIDIA's Rubin and Rubin Ultra platforms are expected to widely adopt HBM4E. Samsung is accelerating the scale deployment of 1c DRAM process and plans to triple HBM output in 2026 compared to 2025.

Capacity Bottlenecks and Price Increase Expectations: The Sustainability of the HBM Boom Cycle

The stock price surge triggered by the HBM4E sample event essentially reflects the market's strong expectation that the high-growth cycle of HBM will continue. But whether this expectation can be realized depends on multiple variables.

Supply Side: Capacity expansion for HBM faces technological and capital constraints. Improving yields for advanced packaging takes time, and new production lines typically take 18 to 24 months to ramp up. Even with aggressive capacity expansion by the three giants, the capacity gap in the short term remains difficult to close.

Demand Side: AI computing investments continue to accelerate. TrendForce indicates that in 2026, demand growth for HBM will be mainly driven by capacity upgrades in AI ASICs, with per-chip HBM capacity increasing from 96/192 GB to 216/288 GB. In 2027, NVIDIA's Rubin Ultra platform will further push GPU HBM capacity to 384 GB per unit.

Pricing: HBM contract prices experienced structural declines in 2026, somewhat suppressing SK Hynix's overall product prices. However, institutions expect HBM contract prices to increase several times in 2027. The persistent supply-demand gap provides fundamental support for price hikes.

Nevertheless, risks exist. SK Hynix's stock has already risen over 300% this year, with the market pricing in high growth expectations for AI memory. The continuation of the rally will depend on the mass production schedule of HBM4E, yield improvements, customer adoption speed, and price trends. If AI capital expenditure remains high, SK Hynix could benefit from shortages of high-end memory and product mix upgrades; but if supply expands faster than demand, the market's valuation of the high-margin HBM cycle could be revised downward.

Summary

SK Hynix's HBM4E sample delivery is not an isolated corporate event but a concentrated reflection of the AI computing arms race in the storage chip sector. From the dramatic stock price reactions to accelerated technological iterations, from the reshuffling of the "Three Kingdoms" pattern to the ongoing capacity shortages, this event reveals the ongoing structural transformation in the semiconductor industry.

HBM has evolved from a segment of DRAM into a strategic resource for the AI era. The customer validation and mass production race for HBM4E will directly determine the supply capacity and cost structure of AI accelerators in 2027 and beyond. For investors, the high-growth cycle of HBM is supported by solid supply-demand fundamentals, but the market's early pricing also entails risks of volatility. Tracking the progress of HBM4E mass production, customer adoption, and price trends will be key to assessing the future trajectory of this sector.

Frequently Asked Questions (FAQ)

Q1: What are the main differences between HBM4E and HBM4?

HBM4E is an enhanced version of HBM4, with significant improvements in bandwidth, capacity, and power efficiency. HBM4E's pin rate can reach up to 16 Gbps, with per-stack bandwidth up to 4.0 TB/s, about 38% higher than HBM4; it achieves 48 GB capacity through 12-layer stacking; power efficiency is improved by over 20%, and thermal resistance is reduced by about 17%.

Q2: How is SK Hynix's competitive position in the HBM market?

SK Hynix is currently the global leader in HBM. In Q1 2026, its market share was approximately 55.5% to 58%, ahead of Samsung (~21-23%) and Micron (~21%). Major clients include NVIDIA, AMD, and Google.

Q3: When is HBM4E expected to mass produce?

HBM4E plans to begin mass production in 2027. Customer testing and validation are expected to be completed in the second half of 2026. SK Hynix states it will work closely with partners to ensure timely mass production.

Q4: What is the supply-demand situation in the HBM market?

The HBM market is currently in a severe supply shortage. In 2026, the market size is expected to grow 58% to $54.6 billion, but even with 70% of new capacity allocated to HBM, the capacity gap remains 50-60%. Institutions project this structural shortage will last at least until 2028.

Q5: Which AI chips will HBM4E be used in?

HBM4E is expected to be used in NVIDIA's Rubin Ultra platform planned for 2027, AMD's Instinct MI500 series, and other next-generation AI accelerators.