VW will share its MEB electric vehicle platform with Ford, the source said.
Volkswagen's supervisory board is due to discuss deepening the alliance at a meeting on July 11, 2019, a second source told Reuters.
A VW spokesman declined to comment on the details of a potential alliance but said that talks with Ford are progressing well.
A Ford spokeswoman said, "Our talks with Volkswagen continue. Discussions have been productive across a number of areas. We'll share updates as details become more firm."