Abstract The return of stolen assets represents a ‘fundamental principle’ of the United Nations Convention against Corruption (UNCAC). The convention’s inclusion of a chapter on asset recovery was considered a groundbreaking achievement at the time of the treaty’s conclusion in 2003. The treaty negotiations concerning these provisions, however, were highly controversial, and the discussions did not benefit from a substantial body of practical experience concerning the return of stolen assets. In the 20 years since the treaty’s conclusion, states have acquired some experience with asset return, and the gaps and limitations in UNCAC’s regime governing asset recovery have become apparent. Article 57 of UNCAC, concerning asset return and disposal, exemplifies the need for progressive development of international asset recovery laws. Article 57 requires ‘updating’ or supplementation because the provision does not adequately address major recurrent issues, such as the recipients, use and monitoring of returned assets; the transparency of the asset return process; and the participation of civil society in the process. Normative development could involve formal law reform, within the UNCAC legal framework, but it could also involve more informal legal change, outside of the UNCAC regime. The Global Forum on Asset Recovery represents an important example of legal change that raises issues of both accountability and effectiveness.