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Memory is the most cyclical business in semiconductors. SK Hynix has risen ~500% from its 52-week low on the most powerful HBM supercycle in history — 49% operating margins, sold-out production, NVIDIA as anchor customer. But every memory supercycle ends. Samsung is investing tens of billions to close the HBM yield gap. Micron's share is growing from 13% to 24%. When the cycle turns — whether from AI capex slowdown, inventory builds, or competitive yield convergence — SK Hynix's margins compress from 49% to 25-30% within 3-4 quarters, earnings collapse, and the stock gives back a significant portion of its gains. The 500% move means the absolute dollar downside is enormous. The HBM content multiplier (8→12 stacks per GPU) provides a structural floor that previous memory cycles lacked, but it delays the peak rather than eliminating cyclicality.

If SK Hynix maintains its HBM yield lead through HBM4, HBM5, and beyond — if each new generation widens rather than narrows the competitive gap — SK Hynix becomes the TSMC of memory: the company that controls the most critical component in AI infrastructure with near-monopoly positioning. HBM TAM reaches $100B+ by 2028. SK Hynix captures 55%+ with 45-50% operating margins sustained across the cycle. Revenue exceeds KRW 200T. Market cap approaches $1T. The memory cyclicality that has defined the industry for decades is partially broken because HBM supply remains structurally short as AI compute demand compounds faster than fab capacity can be built. SK Hynix becomes the second most important company in the AI hardware supply chain after TSMC — the memory monopolist whose production schedule determines when the world's AI infrastructure gets built.