Prohibiting Anticompetitive Mergers Act of 2022 This bill prohibits certain business mergers, modifies the procedures for reviewing mergers, and establishes procedures for reversing certain mergers. Specifically, the bill prohibits mergers that (1) are valued at more than $5 billion in total assets, (2) result in the acquiring entity having a market share of greater than 33% (or a share of a labor market as an employer of greater than 25%), or (3) result in market concentration levels that exceed specified thresholds. The bill also expands the authority of the Federal Trade Commission (FTC) and the Antitrust Division of the Department of Justice (DOJ) to review pending mergers, including whether a merger is likely to harm the competitive process and the effect of a merger on relevant labor markets. Finally, the bill authorizes the FTC and the Antitrust Division of the DOJ to retroactively unwind mergers that are prohibited under the bill or that meet certain other anticompetitive criteria such as a merger that results in a greater than 50% share of a relevant market.