Wirecard struck an alliance in April with SoftBank, whose Vision Fund is behind ride-hailing companies such as Uber, Didi Chuxing, Grab and Ola. As part of the pact, SoftBank is also buying $1 billion in convertible bonds from Wirecard.
The investment by the world's biggest private technology company marked a vote of confidence after Wirecard faced allegations of fraud in a series of investigative reports by the Financial Times.
AUTO1, the Berlin-based car trading platform, will offer individual financial services via Wirecard's boon smartphone payments and banking app, the companies said in a joint statement.
Wirecard has told shareholders it sees profit potential of between 209 million euros and 273 million euros ($235-$307 million) from its SoftBank alliance over five years. The Japanese conglomerate had invested $460 million in AUTO1 last year.
(Reporting by Douglas Busvine, Editing by Sherry Jacob-Phillips)