"Digitalization is a major factor in the success of retail banks," Claes Fornell, ACSI chairman and founder said. "As for the future of banking, firms that best match technology with customer needs will be big winners; those that don't will face existential threats."

Credit unions are stable at an ACSI score of 82, compared to last year's index. According to the report, members appreciate that credit unions are opening more branches (+4%) and ATMs (+6%), but at 71 these remain the lowest-rated aspects of the credit union experience. The variety of financial services offered also has improved from last year (84). Staff courtesy and helpfulness is still strong at 89, but down a point from a year ago and service is slightly slower as branches get busier (-2% to 87).

Members also report that interest rates seem less competitive (79). On the other hand, credit unions have made it easier to add or change accounts (84), and are doing a better job of helping customers understand their accounts (83).

Banks Regional and community banks improved the most, up 2.4% to 85. National banks rank lowest, but gained 1.3% to 78. Steady at 79, super-regional banks are in the middle, both in terms of size and service.

Citibank remains the highest-scoring national bank despite slipping 1% to 81. In second place, Chase gained 5% to 79, the biggest improvement of any individual bank. Chase's investments in its website, mobile banking, peer-to-peer payment services and ATMs have all helped boost the bank to its highest ACSI score ever. 

Bank of America also continued to adopt emerging technology, climbing 3% to 77. Its customers use digital banking more than any other channel. Meanwhile, Wells Fargo continued to struggle, falling 3% to last place at 74. 

The ACSI report, a national economic indicator of customer evaluations of the quality of products and services available to household consumers, is based on 17,861 customer surveys collected between October 1, 2016, and September 16, 2017.