A group of U.S. states led by New York is investigating Facebook for possible antitrust violations and plans to file a lawsuit against the social media giant next week, four sources familiar with the matter said on Wednesday.

The complaint would be the second major lawsuit filed against a Big Tech company this year. The Justice Department sued Alphabet Inc's Google in October.

More than 40 states plan to sign on to the lawsuit, one source said, without naming them.

Facebook declined to comment.