Abstract: Sixty years after the end of World War II much of the artwork looted or forcibly sold during the war has yet to be returned to its rightful owners. One of the primary problems encountered by individuals pursuing claims is that it is difficult to locate the necessary documentation on provenance. Organizations with information on a piece’s history, museums in particular, often have a disincentive to share information that could assist in an heir’s claim. A mandatory reporting requirement, for government and museum officials with unique access to information on provenance, would counterbalance that reluctance, and address the most basic stumbling block survivors and heirs encounter in building legal claims for recovery. While this obligation would work best if implemented in a binding international agreement, negotiating binding international agreements in this arena has proven difficult. The United States has been a leader in this field and is uniquely positioned to model a policy of mandatory reporting. The United States government should act unilaterally to transform the moral responsibility of government bodies and museum officials into an enforceable legal duty.