JPMorgan Chase has upgraded products and technology in four states to link in the final 822 former Washington Mutual branches to the Chase computer system.

The bank said that following the up-gradation, all Chase bank accounts across the country will be on one computer system. As a result, more than 25m customers can access their accounts at any of the more than 5,100 Chase branches and more than 15,000 ATMs, 13 months after Chase purchased WaMu’s banking operations.

Moreover, the conversion of 11.6m accounts in California, Arizona, Nevada and Colorado represents $63.6 billion in deposits. Nearly 1.2m loan accounts with approximately $62 billion in balances were also converted to Chase systems.

The four-state conversion is the last of three retail conversions to bring all former WaMu branches onto Chase’s computer systems and under the Chase brand. With this latest conversion, customers have full access at any of 5,126 Chase branches in 23 states and 15,038 Chase ATMs in 26 states.

Charlie Scharf, head of retail financial services at Chase, a part of JPMorgan Chase, said: “Our customers all across the country now benefit from our employees’ terrific work. We created better service and convenience far faster than in previous conversions and far faster than any other bank has done.”