The potential investigations have been welcomed by some consumer advocates, who say big technology companies stifle competition and hold too much sway over speech and commerce.
But some legal experts said the investigations may not lead to major reforms, noting that U.S. law makes it difficult to prove an antitrust violation.
The following answers some questions about the basics of U.S. antitrust law and what regulators will focus on:
What are antitrust laws for?
Antitrust laws seek to promote fair competition.