Micron Technology, Inc. (MU)

The company produces DRAM and NAND flash. The product is close to a commodity: buyers choose on price and availability rather than on the maker's name. Profit therefore swings by multiples — from losses in years of oversupply to records during shortages — and cannot be extrapolated from last quarter's revenue.

The line the market watches most closely is high-bandwidth memory, HBM, which sits alongside accelerators used to train models. Output is constrained and contracted in advance, margins exceed ordinary DRAM, and the HBM share of sales currently governs how investors view the company.

Manufacturing is in-house and capital-intensive: fabs take years to build, and expansion decisions are made years ahead of knowing the future price. That is the sector's central risk — every player adding capacity at once and prices collapsing. Micron pays a small dividend.