WASHINGTON — Bank earnings rose over the summer to their highest level in more than four years, and the number of troubled banks fell for the second straight quarter, federal regulators reported Tuesday.

The Federal Deposit Insurance Corp. said the banking industry earned $35.3 billion in the July-September quarter. That’s up from $23.8 billion in the same period last year. More than 60 percent of banks reported improved earnings.

The better earnings and fewer troubled banks suggest that the industry is steadily improving from the depths of the 2008 financial crisis.

“Bank balance sheets are stronger in a number of ways, and the industry is generally profitable, but the recovery is by no means complete,” said Martin Gruenberg, FDIC’s acting chairman.

The FDIC also said there were 844 banks on its confidential “problem” list in the quarter, or about 11.5 percent of all federally insured banks. That was down from 865 in the April-June period, which was the first quarter in five years to show a decline.

Banks with assets exceeding $10 billion drove the bulk of the earnings growth. They made up 1.4 percent of all banks but accounted for about $29.8 billion of the industry’s earnings in the third quarter.

Those are the largest banks, such as Bank of America Corp., Citigroup Inc., JPMorgan Chase & Co. and Wells Fargo & Co. Most of these banks have recovered with help from federal bailout money and record-low borrowing rates.

FDIC officials say the bulk of the gains were because banks, especially credit card companies, set aside less money for potential losses. In the July-September period, banks put aside $18.6 billion. That’s the lowest amount in four years.

But the industry continues to struggle with flat growth in loans. Banks’ loan balances increased $21.8 billion in the third quarter. That was a modest gain. But it marked the second straight quarter in three years that balances have grown, the FDIC said.

“After three years of shrinking loan portfolios, any loan growth is positive news for the industry and the economy,” Gruenberg said. Still, lending is well below healthy levels.

So far this year, 90 banks have failed. That’s down from the 157 banks shuttered last year – the most for one year since the height of the savings and loan crisis in 1992 – and 140 in 2009.

Most of the banks that have struggled or failed have been small or regional institutions. They depend heavily on loans for commercial property and development – sectors that have suffered huge losses. As companies shut down during the recession, they vacated shopping malls and office buildings financed by those loans.

Still, large banks are less profitable than they were before the 2008 financial crisis.