Ally Financial Inc. fell after Chief Financial Officer Russ Hutchinson highlighted intensifying credit deterioration among its borrowers and said the auto-lender may experience some underperformance.

Borrowers have shown signs of vulnerability throughout the year and August US jobs data underscored those stresses, according to Hutchinson. The pain is mostly linked to the firm's retail auto loan book, he said at a Barclays Plc conference.

Shares in the auto lender fell as much as 18% on Tuesday morning, the most intraday since March 2020, with fellow consumer lenders following suit.

"Over the course of the quarter, our credit challenges have intensified," Hutchinson said on Tuesday. "Our borrower is struggling with high inflation and cost of living and now, more recently, a weakening employment picture."

The firm may experience some underperformance, he said, adding that Ally will evaluate reserves to cover bad loans and increase them if needed. Auto loan delinquencies and net charge-offs came in higher than expected for July and August, Hutchinson said.

Last week's jobs report fell short of estimates ahead of likely Federal Reserve rate cuts later this month. Detroit-based Ally is best known for auto lending, but also offers credit cards, checking and savings accounts, and home loans.

Hutchinson said the firm will focus more on capital and expenses moving forward, though is not updating its guidance at this time.

RBC Capital Markets analyst Jon Arfstrom expects the firm's guidance to change, predicting the outlook for net charge-offs will increase, he wrote in a note Tuesday.