Ecosystem market caps listed

A fresh market-cap snapshot shows investors are pricing more of the artificial-intelligence hardware stack than just chip designers and cloud giants. (companiesmarketcap.com) As of April 2026, SanDisk was valued at about $126.8 billion, Western Digital at about $115.8 billion, Seagate at roughly $105 billion to $111 billion depending on the data source, Lumentum at about $63.8 billion, Coherent at about $57.7 billion, and ASE Technology at about $54.1 billion. (companiesmarketcap.com, companiesmarketcap.com, stockanalysis.com, companiesmarketcap.com, companiesmarketcap.com, stockanalysis.com) Those companies sit in different parts of the same supply chain. SanDisk, Western Digital and Seagate sell storage; Lumentum and Coherent make optical and photonic parts that move data with light; ASE packages and tests chips after wafers come out of fabs. (sandisk.com, lumentum.com, coherent.com, aseglobal.com) The storage names look different than they did a year ago because SanDisk and Western Digital split on February 24, 2025. SanDisk became a standalone Nasdaq-listed flash-memory company under the ticker SNDK, while Western Digital kept the hard-disk-drive and platform business. (sandisk.com, westerndigital.com) Photonics is the business of sending information as light instead of electrical signals over copper. Lumentum said in March 2026 that it was demonstrating products for “scale-out, scale-up and scale-across” artificial-intelligence infrastructure and opening a United States factory for advanced lasers for large AI data centers. (lumentum.com) Coherent made the same pitch at the Optical Fiber Communication Conference in March 2026, highlighting 3.2-terabit transceivers, co-packaged optics and other optical links aimed at bandwidth and energy-efficiency limits inside AI systems. (coherent.com) Packaging is the less visible step that turns finished silicon into something a server maker can mount and cool. ASE describes itself as an assembly-and-test provider, handling packaging, wafer probing and final test work that has become more important as artificial-intelligence chips use more complex multi-chip designs. (aseglobal.com, photonics.com) The market-cap list is not a bill of materials for one server, and it does not mean these companies are equal beneficiaries of artificial-intelligence spending. It does show that public markets are assigning large equity values to storage, optics and packaging businesses that sit behind the better-known graphics-processing-unit trade. (companiesmarketcap.com, companiesmarketcap.com, stockanalysis.com) That is the shift in the latest snapshot: the artificial-intelligence buildout is being valued not only in processors, but in the companies that store the data, move it, and turn bare chips into deployable hardware. (companiesmarketcap.com, companiesmarketcap.com, aseglobal.com)