U.S. fund manager OppenheimerFunds, the largest holder of Puerto Rico debt among U.S. municipal bond funds, warned the island it stands ready to defend the terms of bonds it holds, a day after the governor said he wanted to restructure debt and postpone bond payments. Puerto Rico’s Governor Alejandro Garcia Padilla could be heading toward a fight with creditors unwilling to take reduced payouts as he tries to restructure the island’s $73 billion debt to relieve its fiscal problems.