Much recent research argues that case markers frequently have a richer internal structure than their surface appearance suggests. Furthermore, based on cross-linguistic facts about phenomena like suppletion and syncretism, work in this vein argues that case features involve an implicational containment hierarchy, in which (among other relations) oblique cases contain the features of accusative case. Using fieldwork data on Balkar, a vulnerable Turkic language spoken in southern Russia, I argue for new evidence that oblique cases contain the accusative. In brief, Balkar shows an alternation in certain possessed NPs that is endemic to accusative and oblique cases, in precisely the way that the case containment hypothesis predicts.