Private regulation by dominant firms and the digital infrastructure of democracy controlled by some firms constitute the areas where the separation of powers principle, envisaged in a broad sense, and antitrust may share much common ground. A single dominant digital firm may adopt private regulation affecting an entire industry and even society at large, be an important part of the digital infrastructure of democracy and, through many means including lobbying, exercise a significant influence on public decision-makers. Such a firm concentrates an immense amount of politico-economic powers. At the same time, it is subject to antitrust laws and relevant from a contemporary and prospective separation of powers’ viewpoint. Antitrust could, in the end, contribute to the separation of powers in the digital era and, ultimately, to trust. Antitrust for trust, or the ultimate apparent antitrust paradox.