 A fourth approach to business ethics is called the “market failures approach” (MFA). It originates with McMahon (1981), but it has been developed in most detail by Heath (2014) (for discussion see Moriarty 2020 and Singer 2018). According to Heath, the justification of the market is that it produces efficient—in the sense of Pareto-optimal— outcomes. But this only happens when the conditions of perfect competition obtain, such as perfect information, no market power, and no barriers to entry or exit. (When they don’t, markets fail—hence the market failures approach.) On the MFA, these conditions are the source of ethical rules for market actors. The MFA says that market actors, including sellers and buyers, should not create or take advantage of market imperfections. So, for example, firms should not deceive consumers (creating information asymmetries) or lobby governments to levy tariffs on foreign competitors (erecting barriers to entry).