Fewer subprime borrowers are paying off their auto loans early, a possible sign that consumers with weaker credit scores are struggling more, according to a report by Wells Fargo & Co. researchers, Bloomberg News reported yesterday. Borrowers are making fewer extra payments on loans that were bundled into bonds in 2015 and 2016, compared with loans in 2013 and 2014 bonds, according to Wells Fargo analysts led by John McElravey. The data on prepayments may offer another sign that subprime consumers are having more trouble paying their bills, the analysts wrote in a note on Tuesday. Borrowers are already defaulting on a growing amount of auto debt. Last decade, slower monthly payment rates on credit cards were an early sign of the consumer credit cycle changing for the worse, the analysts wrote. For auto loans, slower prepayment may be more of a coincident indicator than a leading one, they wrote.