Mayville Engineering Company (MEC) is a U.S.-based contract manufacturer that makes highly engineered metal components and assemblies for large OEM customers across several industrial end markets. MEC is not a product company — it makes the parts that go inside its customers' products, handling laser cutting, stamping, tube bending, welding, brake press forming, aluminum extrusion, coating, and assembly. MEC claims to be the largest metal fabricator in the U.S. by revenue. MEC sells directly to OEMs through a technical, consultative sales process, engaging early in the customer's product development cycle to design parts for manufacturability — a model that deepens integration and raises switching costs. Key end markets include heavy- and medium-duty commercial vehicles (~32% of net sales), powersports (~16%), construction and access equipment (~15%), agriculture (~5-8%), and military. MEC's fastest-growing end market is data center and critical power, which MEC entered via the mid-2025 acquisition of Accu-Fab for roughly $100M in pro forma revenue. MEC targets data center and critical power to exceed 20% of revenue in 2026. Because roughly 55% of MEC's cost structure is fixed, revenue volume is the dominant driver of profitability, making the business meaningfully cyclical. A key feature of MEC's contracts is commodity pass-through, where changes in steel and aluminum prices are passed directly to customers. MEC also points to reshoring trends and OEM outsourcing as structural tailwinds for its 100% domestic manufacturing footprint.