Tower Semiconductor is a pure-play specialty semiconductor foundry — it manufactures wafers exclusively for fabless chip companies and integrated device manufacturers (IDMs) based on their customers' designs, rather than designing or selling its own chips. Tower's core value proposition is its portfolio of specialty analog and mixed-signal process technologies, the most important of which is Silicon Photonics (SiPho). Tower manufactures photonic integrated circuits used in optical transceivers for data center interconnects, and claims roughly 80% market share in SiPho IC manufacturing. SiPho and Silicon Germanium (SiGe) BiCMOS — used for complementary optical transceiver components — together represented about 27% of FY25 revenue, and are the fastest-growing and highest-margin products. Tower's other key platforms include RF SOI antenna switches for smartphones (~23% of revenue), power management ICs (~16%), and CMOS image sensors and displays (~16%). Tower charges customers on a per-wafer basis, and its cost structure is largely fixed, meaning incremental revenue at higher utilization drops through at high incremental margins. SiPho customers face high switching costs because analog designs are tightly tied to Tower's specific process, and Tower deepens these relationships through proprietary process design kits and engineering support. Tower operates six fabs across Israel, the U.S., Japan, and Italy, and is executing a $920M capex program to expand SiPho and SiGe capacity to meet AI data center demand, targeting over 5x its current monthly SiPho wafer output by end of 2026.