Vividence monitored 4000 consumers as they performed tasks at online banking sites and then benchmarked the banks in categories.

Bank of America topped the overall rankings among both customers and prospective customers. Among current account holders, Bank of America was followed by Citibank and National City. Among prospective customers, Wells Fargo came second after Bank of America, followed by National City.

Vividence says Bank of America ranked highest in part because the site scored well on features such as online bill pay and provided newcomers with an easy way to explore online banking services. Bank of America also performed the best in terms of potential to acquire new customers through the Web site, followed by Bank One and US Bank.

However the study also uncovered a contrast in how banks performed among existing versus prospective customers. The research shows that several banks made it easy for prospective clients to sign-up for new accounts but current customers had problems with features such as online bill pay. In other cases, current customers found sites highly satisfactory while prospective customers found the same sites poorly organised or daunting to explore.

The study also found that banks miss out on online cross-selling opportunities. Customers felt banks should provide them with customised recommendations, but Vividence says several of the largest banks performed the worst at generating customers' interest in additional offers.

Vividence also stressed that banks should ensure that existing technology meets customers needs. The research found that users on average experience a problem on a site almost every two minutes. Common problems include difficulty accessing customer service and unclear instructions for online bill payment.

The study also found that banks are not maximising the potential of their online sign-up tools. Vividence says customers are open to switching banks and find doing so much easier in an online environment. Sites with prominently showcased customer support options performed better at persuading customers to adopt online services.

Jeff Greenberg, chief executive officer, Vividence, says there are a variety of trends - consolidation, cost cutting, competition - that are increasing the importance of the online channel to the banking industry.

"This research clearly shows an opportunity for banks to increase conversion to online banking, improve customer acquisition and grow wallet share by improving the consumer's online experience," says Greenberg.