National Oilwell Varco (NYSE：NOV) is a multinational corporation based in Houston, Texas, which manufactures land-based and offshore oil drilling rigs as well as all the major mechanical components for such rigs. The company also performs a number of services for the oil industry such as well and pipeline inspections and is one of the market leaders in supply chain management through their distribution network of over 150 locations.
Products include all the heavy hardware for oil well drilling as well as drilling instrumentation and controls and drilling power generation and control. Partial list of heavy hardware includes topdrives, rotarys, drawworks, derricks, BOP's (blowout preventers), mud pumps, riser equipment, and complete drilling rigs. Products also include instruments and controls required on the rig floor for the drilling operation. This includes sophisticated electronics for precise control. Further, NOV produces control electronics for power generation and control of drilling motors, and MCC's (motor control centers) for AC motor control. It also manufactures other equipment used in oil production, including reciprocating multiplex
In 2008 National Oilwell Varco was ranked the number one company in Houston, Texas by the Houston Chronicle, having ranked number fifteen the year before.
NOV's two main predecessors, Oilwell Supply and National Supply, were founded in 1862 and 1894, respectively. These two companies manufactured and distributed a number of components for the oil drilling industry including drawworks, mud pumps and derricks.
In 2005, National Oilwell and Varco merged to become National Oilwell Varco.
In December 2007, NOV announced a buyout of Grant Prideco Inc.
The company now employes over 25,000 people and has over 600 facilities worldwide. As of 2008, it is the largest oil well drilling services company ahead of Schlumberger, Halliburton and Baker Hughes.