MILAN (Reuters) – Fiat Chrysler (FCHA.MI) and Peugeot owner PSA (PEUP.PA) aim to sign a final merger agreement as early as the beginning of next month, a source familiar with the matter said on Saturday.

The two automakers said earlier this week they planned to join forces in a 50-50 share merger to create the world’s fourth-largest automaker, seeking scale to cope with costly new technologies and slowing global demand.

They said they aimed to reach a binding deal on the $50 billion merger “in the coming weeks”.

The source said the two groups were at work to finalise all the merger details and they hoped to sign a binding memorandum of understanding in “three-four weeks”.

“This means the final agreement should be signed by early December, or by Christmas at the latest,” the source said, confirming a report published earlier on Saturday in La Stampa daily newspaper.