The U.S. consumer watchdog reported widespread failures in the servicing of student loans on Tuesday and urged new rules to protect borrowers. “With one out of four student loan borrowers struggling to repay their loans or already in default, cleaning up the servicing market is critical,” Richard Cordray, director of the Consumer Financial Protection Bureau, said in a statement. Student loans are the second-largest U.S. consumer debt market, which has more than doubled from less than $600 billion in 2006 to more than $1.2 trillion currently, the bureau said.