Celestica, Inc. (CLS)

Celestica assembles electronics to other people's designs, and data-centre hardware lifted it.

A contract manufacturer does not own the product: it buys components, assembles and tests the device for the customer. Margins are thin by nature, and the result is decided by purchasing discipline, capacity utilisation and the ability not to be left holding unsold component inventory.

The turning point was networking hardware for large cloud operators: switches and racks for model training are ordered in big lots and require engineering involvement, not assembly alone. That lifted both volume and margin. The risk is concentration — a few customers supply most of the revenue, and a shift in their programme shows immediately. The company pays no dividend but buys back stock.