A failed attempt to charge a monthly debit usage fee contributed to Bank of America being ranked last in a customer satisfaction index.

Of the four banks looked at by the American Customer Satisfaction Index in its new annual report — Citigroup, JPMorgan Chase, Wells Fargo and Bank of America – BofA had a score of 68.

ACSI assigned scores on a scale of zero to 100 and tracked credit unions, insurance companies and other sectors within the financial industry.

In last place for customer satisfaction within the banking sector, ACSI said BofA faced “unresolved revenue challenges” after scrapping its plans to charge new debit card fees.

Last year's leader, Wells Fargo, kept its customer satisfaction stable, but a 6% improvement for Citigroup placed the two in a tie for first at 73, according to ACSI. Citigroup's score reflected customer satisfaction with services of its Citibank division, ACSI said.

“In the aftermath of the subprime mortgage crisis, Citibank is shrinking as it closes branches and serves fewer customers. The customers who have chosen to stay are more satisfied,” the index noted.

The second gainer among four banks, JPMorgan Chase, improved 4% to 70 and moved past BofA. ACSI said Chase's rebound this year follows a string of ACSI losses, but the bank has yet to return to its pre-financial crisis customer satisfaction level. Still, Chase is now the largest U.S. bank in terms of assets, replacing BofA.

“Because of their size, both small banks and credit unions benefit from an ability to provide more personalized service,” said Claes Fornell, ACSI's founder. “The challenge for these smaller institutions will be how best to maintain high levels of customer service with minimal or no fees amid a major influx of new customers.”