Federal laws and regulations sometimes require non-federal entities to expend their resources to carry out national policies. The Unfunded Mandates Reform Act of 1995 (UMRA), enacted as Public Law 104-4, defines many of those requirements as federal mandates. The law aims to ensure that Members of Congress receive information about the potential effects of mandates as they consider proposed legislation and that federal agencies take information about mandates into account as they weigh proposed regulations. To that end, UMRA requires the Congressional Budget Office (CBO), at certain points in the legislative process, to assess the cost of mandates that would apply to state, local, and tribal governments or to the private sector; it also requires most federal agencies to estimate those costs and other effects in the course of promulgating regulations to implement such mandates. This report describes CBO’s role in assessing the impact of private-sector mandates during the legislative process and provides information about the private-sector mandates that have become law during the past decade.