Business actors often act in ways that may harm other parties. While the law aims to restrict harmful behavior and to provide remedies, legal systems do not anticipate all contingencies and legal regulations are not always well-enforced. This article argues that the logic of double effect (LDE), which has been developed and deployed in other areas of practical ethics, can be useful in helping business actors decide whether or not to pursue potentially harmful activities in commonplace business activity. The article illustrates how LDE helps to explain the exploitative nature of payday lending, the distinction between permissible and impermissible forms of market competition, and the potential wrong of imposing risk of harm on others. The article also addresses foundational debates about LDE itself. We offer the article as an illustration of the sort of “midlevel” theorizing that can address directly the needs of practitioners.