ABSTRACT Many recent articles argue that participants who seroconvert during HIV prevention trials deserve treatment when they develop AIDS, and there is a general consensus that the participants in HIV/aids treatment trials should have continuing post‐trial access. As a result, the primary concern of many ethicists and activists has shifted from justifying an obligation to treat trial participants, to working out mechanisms through which treatment could be provided. In this paper I argue that this shift frequently conceals an important assumption: that if there is an obligation to supply treatment, then any party who could provide it may be prevailed upon to discharge the obligation. This assumption is false. The reasons why trial participants should get ART affect who has the duty to provide it. We should not burden governments with the obligations of sponsors, nor researchers with the obligations of the international community. And we should not deprive a group of treatment because their need is less salient than that of research participants. Insisting otherwise may lead to people being wrongfully deprived of access to antiretrovirals.