Sanctions-scarred banks may hold back Iran's economic relief

By Yeganeh Torbati, Anna Yukhananov and Karen Freifeld WASHINGTON/NEW YORK (Reuters) - Major banks wary of heavy U.S. penalties will be reluctant to restore ties with Iran even if sanctions are lifted in a possible nuclear deal, bank executives and advisers say, likely denting Iran's ambition to attract foreign investment to revive its crippled economy. After years of being frozen out of the global banking system and most trade with the West, Iran is eager for sanctions to be lifted so it can dr