This article addresses one aspect of the United States’ multi-faceted campaign to recover income taxes and penalties on undisclosed offshore accounts – the U.S. Department of Justice’sinvestigation and criminal prosecution of foreign banks that are alleged to have opened and maintained accounts for U.S. taxpayers.  The Department of Justice has argued that by enabling U.S taxpayers to open and maintain accounts that the taxpayers did not report to the Internal Revenue Service, the banks participated in efforts to defraud the United States of taxes owed on the accounts.  The authors examine in particular the impact of the Department of Justice’s Program for Swiss Banks, a voluntary disclosure program negotiated with the Swiss government in which about 100 Swiss banks registered to participate, the extraordinary information being collected, and assess other countries that may become the next focus of investigation.