The Department of Justice's assistant attorney general brought the case against big tech into focus in a new speech delivered at the Antitrust New Frontiers Conference in Tel Aviv on Tuesday.
Makan Delrahim laid out some possible arguments against the tech giants as his office is reportedly taking the lead on investigating Google parent company Alphabet and a potential probe into Apple. The Federal Trade Commission, meanwhile, reportedly has taken jurisdiction over Facebook and Amazon.
Shares of these companies dropped on last week's reports that U.S. antitrust officials were beginning to take action on long-anticipated investigations. But the case against the companies has remained unclear as some tech advocates have argued that old school antitrust laws don't have a place in the digital economy.
Delrahim's speech, as transcribed on the DOJ's website, argues existing antitrust laws are strong enough to regulate tech.
"We already have in our possession the tools we need to enforce the antitrust laws in cases involving digital technologies," Delrahim said. "U.S. antitrust law is flexible enough to be applied to markets old and new."
Google declined to comment on the speech. Apple, Facebook and Amazon did not immediately respond to requests for comment.
Here are some of the possible arguments antitrust regulators could use against Big Tech based on Delrahim's speech: