On Tuesday, the Justice Department announced that it is opening an antitrust probe into America’s biggest tech companies. Assistant Attorney General Makan Delrahim, who heads the DOJ’s Antitrust Division, explained that the broad and sweeping investigation would seek to determine whether tech giants have engaged in monopolistic practices that have “reduced competition, stifled innovation, or otherwise harmed consumers.” This latest DOJ probe is now the second investigation launched by the government into Big Tech, as the Federal Trade Commission is currently conducting a smaller investigation into potential abuses by Facebook and Amazon.

Back in January, Attorney General William Barr expressed concerns over Big Tech’s rapid growth when he told lawmakers, “I don’t think big is necessarily bad, but I think a lot of people wonder how such huge behemoths that now exist in Silicon Valley have taken shape under the nose of the antitrust enforcers. You can win that place in the marketplace without violating the antitrust laws, but I want to find out more about that dynamic.” It now appears that Barr is seeking to answer these questions.

Criticism of Big Tech has become a uniquely bipartisan issue in this era of heightened partisanship. However, the reasoning behind that criticism is not uniform. Conservatives accuse Big Tech of free-speech infringement specifically related to the censorship practices against conservative social-media figures. Leftists like anti-corporate socialist Sen. Elizabeth Warren (D-MA), on the other hand, call for tech giants like Facebook, Amazon, and Google to be broken up simply for being too big.

News of the DOJ’s new antitrust probe sent shares of the four top tech companies down, as Apple, Alphabet Inc. (Google’s and YouTube’s parent company), Amazon, and Facebook combined to lose an estimated $33 billion in premarket trading Wednesday morning. As Wedbush Securities analyst Dan Ives observed, this investigation is a “shot across the bow.”