Two notions of accountability embodied in proposals to reform managed care have different ethical implications. Market accountability requires plans to inform purchasers and consumers about performance and options, in theory legitimizing limits to care through consumer choice. Recognizing the limits of consumer choice, accountability for reasonableness requires that the rationales for limits to services be public and be based on reasons or rules that "fair-minded" people can agree are relevant to pursuing appropriate patient care under necessary resource constraints. Accountability for reasonableness educates clinicians and patients about the need for limits and empowers a more focused public deliberation in which ultimate authority for limiting care rests with democratic processes.