London (CNN Business) Fiat Chrysler and Peugeot owner PSA Group have signed a binding merger agreement, solidifying a nearly $50 billion deal that will create the world's third largest automaker.

The companies said in a joint statement Wednesday that they expect the 50-50 merger to be completed within 12 to 15 months, pending approval from shareholders and regulators.

The deal, which was first announced in October , should help spread the huge cost of developing electric and autonomous vehicles and help the mid-sized carmaker compete with larger rivals. The combined company would have roughly 410,000 employees and annual revenues of $190 billion.

Fiat Chrysler FCAU PSA PUGOY General Motors GM Toyota TM andsold a combined 8.7 million vehicles last year, just ahead of, which sold 8.3 million, and not far behind Volkswagen and, which each sold over 10 million. Renault, Nissan and Mitsubishi Motors, which share some resources as part of an alliance, sold a combined 10.8 million cars last year.

In a statement on Wednesday, the companies said that Chinese carmaker Dongfeng Group had agreed to sell part of its stake in PSA back to the French automaker, a move that could appease US regulators.

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