Two new reports from Fitch Ratings, taken together, indicate a modest weakening in the collateral backing U.S. auto ABS deals is continuing, with perhaps a temporary reprieve thanks to short-term cash flow positives for consumers, mostly tax refunds and lower gasoline prices. Still, the overall outlook is positive. U.S. prime auto ABS collateral has been marginally weakening in the last few years, most recently because of amped-up competition among auto finance companies, Fitch said in a report out this week, based on transactions issued between 2007 and fourth-quarter 2014. “The quality of prime auto loan securitized pools was...