Most antitrust laws are binary "is it or isn't it a monopoly". They're usually concerned with abuse of market power. In the US, we have much more stringent ant

Most antitrust laws are binary "is it or isn't it a monopoly". They're usually concerned with abuse of market power. In the US, we have much more stringent antitrust laws than actually get enforced by the DOJ. So the answer is, yes they're subject to antitrust intervention, but only if the people responsible for antitrust intervention choose to intervene.