Using a monopoly in one area (and how could it not be effectively a monopoly if it prints money) to gain marketshare in another is textbook anti-competitive pra

Using a monopoly in one area (and how could it not be effectively a monopoly if it prints money) to gain marketshare in another is textbook anti-competitive practice though, isn't it? I recognize that I'm using the European legal definition, but that doesn't make it incorrect, just inapplicable in American courts.