A group of U.S. states is investigating Facebook over concerns it wields too much power. Reuters sources say the states, led by New York, plan to file a lawsuit against the social media giant next week over potential antitrust violations. It's not clear what will be in the lawsuit, but Facebook has previously been accused of stifling competition by buying small potential rivals at a premium. These include Instagram in 2012 and WhatsApp in 2014. Facebook's CEO Mark Zuckerberg did not respond to requests for comment, but he has previously argued that the company has a range of competitors. He's also defended the acquisitions, saying he helped smaller tech firms grow into powerhouses. According to a source, more than 40 states are planning to sign onto the lawsuit against Facebook. U.S. tech firms have faced increasing scrutiny over their size and power in recent years. If confirmed, this complaint would be the second major lawsuit filed against a Big Tech company this year. The Justice Department sued Alphabet's Google in October for antitrust violations, accusing it of illegally using its market muscle to hobble rivals.