Can a $25B Investment Surge Sustain Micron’s 20% AI Memory Grab?

Behind every cutting-edge AI chip is a critical bottleneck: the memory required to feed it data. High-bandwidth memory (HBM) is now so highly sought after that the entire industry, including SK Hynix, Samsung, and Micron (MU), is completely sold out through 2026.

But the real story of this supply squeeze is the sudden shift in who is actually capturing that demand. In just one product generation, Micron has transformed from a relatively minor player into a serious challenger, aggressively capturing a roughly 20% slice of the global HBM market. Now, the company is doubling down by committing to a massive $25 billion capital expenditure plan for FY2026.

The question for investors? Is this historic investment surge enough to break Micron out of the memory sector’s notorious boom-and-bust cycle, and does it finally set the stock up for a long-overdue re-rating?

The Numbers That Tell Micron’s Story

Micron is expanding faster than the market. In Q4 2024, it held 9% of the global HBM market by revenue.  By Q4 2025, it reached 21%. The market itself roughly doubled over that period.

SK Hynix remains the leader with about a 57% share as of Q4 2025, while Samsung has seen some headwinds after issues with its HBM3 packaging and delays in securing qualification from Nvidia.

Micron stepped in and captured that demand and, by all accounts, looks set to expand its market share further.

Why Is HBM So Important For Memory Manufacturers? 

HBM is tightly integrated into AI accelerators and data center systems. The qualification cycles of customers are long, and customers commit to supply years in advance often with prepayments.

HBM also requires approximately three times the wafer capacity of standard DRAM. This pulls supply out of the broader memory market and creates a structural undersupply that supports pricing even beyond AI demand.

How Has Micron Been Winning Share?

SK Hynix remains the leader in the HBM market. It mastered its packaging process earlier than anyone else, secured preferred supplier status with Nvidia (NVDA), and locked in the volume contracts that defined that era.

Micron, on the other hand, spent the period repositioning its product roadmap around the problem that HBM3 exposed but did not fully solve: “heating”.

Stacking memory layers creates a thermal problem that compounds with each generation. The latest HBM4 generation targets sixteen layers. Micron’s answer is hybrid bonding, replacing the solder bumps between layers with direct copper-to-copper fusion, which removes thermal resistance at each junction.

Micron invested and built a large patent position: 621 HBM-related patents vs 315 for SK Hynix. The result? Micron’s HBM3E product, which claims approximately 30% lower power draw than competing designs.

Is The Valuation Still Reasonable?

While trailing PE may be at 15+ for Micron, the forward multiple is very low. It trades at about 6.5x FY2026 consensus earnings and a mere 4x FY 2027 earnings. (See Micron Valuation metrics)

The market continues to treat memory as cyclical, with earnings expected to decline after peaks. There is a possibility that HBM softens part of that pattern.

It is tightly integrated, supply constrained, and sold through long qualification cycles with multi-year contracts and prepayments. Micron’s share gains, product positioning, and contract structure suggest a more durable earnings profile.

The key question is whether this holds as HBM4 scales. The capex trajectory and nature of some recent contracts suggest things could hold up which would mean a re-rating of stock could happen.

How Can A Re-Rating Happen?

For Micron to re-rate, the market needs evidence that earnings are not just peaking higher but sustaining longer.

Early signals are forming. The company plans to spend about $25 billion in FY2026, nearly double the prior year, with a likely focus on HBM capacity. This signals confidence in the outlook. More importantly, it has already begun locking in demand ahead of supply. Its first five-year HBM supply agreement, covering both volume and pricing, marks a structural shift away from short-term pricing cycles toward more visible, contracted revenue.

However, the counterforces are just as important. SK Hynix is spending KRW 40 trillion, roughly $29 billion, on capex in 2026 per S&P. That’s over $54 billion in capex between the two companies. Samsung is also scaling aggressively. If this pace continues, the risk of eventual oversupply remains. At the same time, the cycle still depends on sustained AI investment by hyperscalers such as Alphabet (GOOG) and Amazon (AMZN). If hyperscalers face pressure to deliver stronger returns, spending could slow, feeding directly back into memory demand. (See How low can MU stock go)

Is Micron Stock The Right Investment For You?

While Micron’s HBM momentum makes the story compelling, the risks are real. Execution, supply expansion, and dependence on sustained AI spending all need to hold for the thesis to play out.

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