Many development finance institutions have responded to calls for accountability for social and environmental harms associated with their lending by creating Independent Accountability Mechanisms (IAMs). We argue that IAMs can, at their best, provide relief for those concerned with the nature of the implementation of development projects, thereby addressing what we call immanent complaints about social and environmental impacts. However, IAMs are poorly placed to address what we call contestational grievances: those that entail a rejection of core tenets of the lending institution's development model. Such contestational grievances frequently arise when communities and their supporters reject the commodification of land and associated displacement of people and their livelihoods. Analysis draws on the International Finance Corporation Compliance-Advisor-Ombudsman (IFC CAO)'s handling of a complaint about the palm oil company Wilmar in Indonesia. We argue that because the CAO is institutionally embedded within the IFC, it shares its normative grounding with the institution it holds to account, and therefore risks organising and legitimating accountability failures related to contestational land-based grievances.