According to Bloomberg.com, U.S. prosecutors are thinking about revoking settlements in currency manipulation settlements that were agreed upon years ago and going after banks for manipulating interest rates. The Department of Justice is looking at whether banks violated the earlier deals that resolved those investigations, which stipulated that they would not break the law. If the government finds that banks did in fact commit crimes after the earlier settlements were reached it would be able to revoke those deals.
It has been a common practice for the DOJ to offer deferred prosecution and non-prosecution settlements in probes involving a number of matters, including market manipulation and violations of sanctions. Banks admit responsibility while cooperating with the investigation.
To rescind such a deal would be unprecedented. Among the banks that have settled probes over London interbank offered rate, also known as Libor, are Royal Bank of Scotland Group Plc (RBS), Barclays Plc (BARC), and UBS Group AG (UBS).