Fewer Americans fell behind on credit card payments in June, with delinquencies at their lowest this year at major U.S. card lenders, but the results did not stem concerns about the economic recovery.

Credit card delinquency rates have declined steadily since the beginning of the year, signaling that banks should have to write off less debt as uncollectible.But two major lenders, Capital One Financial Corp. and Citigroup Inc., set off concerns Thursday that declines could be coming to an end. If credit quality does not continue to recover steadily, lenders will be weighed down by credit losses that are still high by historical standards.

Delinquency rates, an early warning sign of future losses, were at their lowest of the year at most lenders, but Capital One’s delinquency rate barely inched down to 4.79 percent in June from 4.8 percent in May.

Citigroup’s delinquency rate fell, but its net credit card losses rose to 11.46 percent in June, from 11.16 percent in May.

The shares of most major credit card lenders closed slightly lower on Thursday, with Capital One down the most. Its shares fell 2.85 percent, to $43.26.

The drop in delinquency rates could slow at other lenders over the summer, said Michael Taiano, an analyst at Sandler O’Neill.

Consumers usually have a little more money to pay their bills in the spring because of tax refunds.

But “June’s a little bit of a tricky month, because you get that effect wearing off. So you could see delinquencies come in maybe higher than what some people are expecting,” he said.

JPMorgan Chase & Co. Chief Executive Jamie Dimon sparked more pessimism  Thursday. His bank reported second-quarter earnings that beat expectations, but Dimon told investors it was “too early to say” how much more improvement he could expect in the company’s consumer lending businesses.

Credit card lenders are also bracing for a reduction in their profits after August, when they must implement restrictions on late fees.