Iran has been unable to withdraw much of the unfrozen oil revenue it was to receive under a November interim nuclear deal, a possible complication for efforts to end the decadelong standoff over Tehran’s nuclear ambitions. The problems were outlined in interviews with nearly a dozen Western and Iranian officials and diplomats, bankers and lawyers with knowledge of the issue. An estimated $100 billion in payments for Iranian oil imports has been locked up in accounts in the importing countries in compliance with U.S. banking sanctions that have been among the most effective in pressuring Iran economically. Only $4.2 billion was to be freed up gradually under the interim deal. One reason Iran is having difficulty tapping the unfrozen revenue is that banks remain fearful they could violate tight U.S. financial sanctions, especially while the outcome of talks on a final nuclear deal remains uncertain. If financial institutions […]