Plexus

Founded in 1979 in Neenah, Wisconsin. Where the big EMS firms chase million-unit volumes, Plexus lives on the opposite — high-mix, low-volume: hundreds of different products in small batches, often in tightly regulated fields like healthcare, aerospace, and industrial.

The company sells not just assembly but design and product development, which blurs the line toward an ODM. The business runs on certifications and traceability rather than lowest unit price — few customers, but long contracts.