National Oilwell Varco Corporate Headquarters, Texas

Through a series of acquisitions and mergers, National Oilwell Varco, or NOV, has become one of the largest suppliers of onshore upstream equipment in the USA, and a major international oil equipment supplier worldwide. In addition to selling parts, the company designs and manufactures drilling and production equipment and systems, including drilling motors, pressure control equipment, fishing tools (used to extract components from the bottom of wells), and nearly every component needed on the business end of an oil rig.