The original Hummers were first designed by AM General Corporation, a wholly owned subsidiary American Motors Corporation (AMC), and built in its Mishawaka, Indiana, assembly plant. In 1979, the United States Army was seeking contractors for a new "High Mobility Multi-Purpose Wheeled Vehicle" which could follow the tracks and ruts of full size army trucks (HMMWV). Among the four competitors for the contract, AM General designed an entirely new vehicle to meet the Army's requirements. In less than one year, it was the first to deliver a prototype vehicle. Initial production versions were delivered to the Army's proving grounds in April 1982.After testing was completed AM General was awarded the contract to supply its HMMWV to the United States armed forces. The first models were built in a variety of military-based equipment and versions. The first contract was in 1983, worth US$1.2 billion to produce 55,000 "Humvees" by 1985. The first production vehicle was assembled by AM General on January 2, 1985. The contract was later increased for an additional 15,000 units.AM General had planned to sell a civilian version of the Humvee as far back as the late 1980s. Having the same structure and most mechanical components, the civilian Hummers were finished in automotive gloss paint, adding passenger car enhancements such as air conditioning, sound insulation, upgraded upholstery, stereo systems, wood trim, and convenience packages. The civilian model began in part because of the persistence of Arnold Schwarzenegger, who saw an Army convoy while filming a movie.In 1992, AM General began selling a civilian version of the M998 Humvee vehicle to the public under the brand name "Hummer". In December 1999, AM General sold the brand name to General Motors, but continued to manufacture the vehicles. GM was responsible for the marketing and distribution of all Hummers produced by AM General. Shortly thereafter, GM introduced two of its own design models, the H2 and H3, and renamed the original vehicle H1. AM General continued to build the H1 until it was discontinued in 2006.