The Department of Justice is launching an antitrust probe into some of the world’s biggest and most influential tech companies, the agency announced Tuesday.

The department’s Antitrust Division, which is responsible for reviewing and enforcing issues relating to mergers, monopolies, competition, and price-fixing, said its review would “consider the widespread concerns that consumers, businesses, and entrepreneurs have expressed about search, social media, and some retail services online.”

“Without the discipline of meaningful market-based competition, digital platforms may act in ways that are not responsive to consumer demands,” Makan Delrahim, head of the Antitrust Division, said. “The Department’s antitrust review will explore these important issues.”