Automobile manufacturers are among the largest companies in the world. These corporations are often multinational, meaning they are partially owned by several foreign companies. These companies often share parts, or use parts made in foreign factories. The U.S. automobile industry produced 12.8 million vehicles in 2000. The three major automobile manufacturers in the United States—General Motors Corporation, Ford Motor Company, and DaimlerChrysler AG—provide three-fourths of the industry's total direct employment in the United States.
Automotive parts manufacturers are another large section of the U.S. auto industry, comprising about 5,000 firms, including Japanese, European, and Canadian companies. These firms supply the original equipment market (for manufacture) and the replacement parts market (for maintenance and repair). Numerous other industries support the automobile industry. These include the insurance, security, petroleum, and roadway design and construction industries. Still other industries, such as motels, drive-in theaters, and fast-food restaurants, owe their existence to the mobility provided by the automobile.