In a series of transactions between 1929 and 1931, the Opel family sold their business, Adam Opel AG, to General Motors Corporation, of which it became a subsidiary. In 1936, Opel sold its bicycle plant to NSU in Neckarsulm (which had started making bicycles at about the same time as Opel). Under the company's many different names, 2.5 million bikes had been produced in all.