HC

Hanover Compressor Company

A maker of natural gas compression equipment and services, Hanover helped keep the pressure up so gas could flow from wells through pipelines to processing plants. Born in 1990 as an "afterthought" of Houston-based Hanover Energy, it grew by buying up compressor rental companies across Texas and Louisiana. In 2007 it merged with rival Universal Compression to form Exterran Holdings, carrying its name into a new era.