We propose an ethical analysis as a method to reflect on how companies’ decisions promote sustainable development. The method proceeds by first identifying the choice according to financial business interests, and by then scrutinizing this choice according to consequentialist and deontological ethics. The paper applies the method to the choice of an Environmental Impact Assessment (EIA) that a consortium of Brazilian companies (EGASUR) delivered as part of their project proposal for the realization of the Inambari hydropower dam in the Peruvian Amazon. We show that if an EIA is chosen based on the attempt to maximize the financial bottom line, it raises ethical issues both from a consequentialist perspective by involving negative consequences for various stakeholder groups, and from a deontological perspective by not complying with relevant rules, guidelines, and principles. The two ethical perspectives hence reveal where the consortium faces impediments to a genuine commitment to sustainability. Building on stakeholder interviews, observations of the project developments, and the executive summary of the actual EIA, we provide indications that EGASUR has indeed made a choice that resembles a decision based on financial interests.