Foreign banks are delaying overhauls to their IT systems and customer onboarding procedures made necessary by a U.S. tax law until their home governments conclude client data-sharing agreements with the United States, according to U.S. officials. On Friday, the Internal Revenue Service extended until June 2014 the cut-off date by which foreign banks choosing to not disclose their U.S. clients under the law, known as FATCA, would face a 30 percent withholding tax on certain payments they receive from the United States. Foreign banks choosing to comply outside of the framework of an Intergovernmental Agreement (IGA) now have until Aug....