There are multiple ways to define the popularity of companies. Market capitalization measures the market value of a publicly traded company and is a proxy for popularity. Major auto manufacturers can be ranked by revenue or unit sales, both of which are published in quarterly and annual reports.

Volkswagen

Volkswagen AG, founded in 1937, is headquartered in Wolfsburg, Germany. Volkswagen sells passenger cars, motorcycles and commercial vehicles under popular brands including Audi, Bentley, Bugatti, Lamborghini, Porsche and Ducati. As of March 2015, Volkswagen had a market cap of $123 billion. The company reported fiscal year 2014 revenue of $75 billion and 10.2 million units sold.

Toyota

Toyota Motor Corporation (TM), founded in 1937, is headquartered in Aichi, Japan. Toyota sells automobiles under brands including Lexus, Scion and Hino. As of March 2015, the company's market capitalization was $239 billion. Toyota reported fiscal year 2014 total sales of $214 billion and 9.1 million units sold.

General Motors

General Motors (GM), founded in 1908, is headquartered in Detroit. GM sells automobiles, parts and financial services under brands including Chevrolet, Buick, GMC, Cadillac and Opel. As of March 2015, GM's market capitalization was $62 billion. The company reported fiscal year 2014 revenue of $156 billion and wholesale volume of 6.0 million. Wholesale volume does not include vehicle sales of unconsolidated subsidiaries. In 2014, unconsolidated subsidiaries sold an additional 3.9 million vehicles.

Ford

Ford Motor Company (F), founded in 1903, is headquartered in Dearborn, Michigan. Ford sells consumer autos and commercial vehicles under the Ford and Lincoln brands. Ford also offers financing services to customers. The company holds minority interest in a number of unconsolidated subsidiaries and is engaged in numerous joint ventures. As of March 2015, Ford's market capitalization totaled $65 billion. The company reported fiscal year 2014 revenues of $144 billion and 6.3 million wholesale units sold.

Honda

Honda Motor Company (HMC), founded in 1948, has headquarters in Tokyo, Japan. Honda manufactures automobiles, motorcycles and power equipment. As of March 2015, Honda's market capitalization was $62 billion. The company reported fiscal year 2014 revenue of $62 billion with 4.3 million units sold.

Nissan

Nissan Motor Company, founded in 1933, has headquarters in Yokohama, Japan. Nissan sells consumer and commercial vehicles under brand names including Infiniti and Datsun. As of March 2015, the company's market cap was $48 billion. Nissan reported fiscal year 2014 revenues of $93 billion with 5.3 million units sold.

Hyundai

Hyundai has headquarters in Seoul, South Korea. As of March 2015, Hyundai's market cap was $43 billion. Hyundai owns 33% of Kia Motors. Hyundai reported fiscal year 2013 revenue of $78 billion with 4.7 million units sold.

Other Manufacturers

Tata Motors (TTM), BMW, Daimler, Tesla (Nasdaq: TSLA), PSA Peugeot Citroen and Fiat Chrysler Auto (FCAU) are other multi billion-dollar auto manufacturers.

Another way to measure popularity is to quantify brand strength. According to Forbes, the most powerful brands among automakers in 2015 were Toyota, BMW, Mercedes Benz, Honda, Audi, Ford, Volkswagen, Chevrolet, Nissan, Hyundai, Lexus, Kia and Porsche, in that order. These brands are all within the top 100 global brands across all industries. Large auto parts companies include Johnson Controls, Delphi and Borg Warner.