The study, which was conducted by Aspen Marketing Services, analysed consumer data from customer households during a 13-month period from February 2006 through February 2007.

It found that customers who received and paid at least three e-bills per month at the SunTrust Web site were 86% more profitable than offline customers and had a 78% lower attrition rate on average.

E-bill users also carried 121% higher deposit balances than the average SunTrust customer and were twice as likely to have a mortgage and 60% more likely to have a savings account with the bank.

CheckFree and SunTrust say the study clearly isolates e-bills as a major factor in driving customer retention and profitability based on a matched sample analysis.

Tom Bennett, director of consumer deposits and access services at SunTrust, says: "This landmark study shows that there is a strong link among online banking, increased profitability and share of wallet, and there's an even stronger link among e-bills, customer loyalty, profitability and usage of other banking products."

CheckFree says the latest study correlates with previous research findings that customers who use EBPP services are more profitable and loyal to their financial institutions.

A 2007 Harris Interactive consumer bill payment survey conducted for CheckFree found that consumers using e-bills reported significantly greater satisfaction with their financial institutions and were more likely to recommend a bank's online offerings to friends and family, and 58% they were less likely to switch financial institutions as a result of using e-bills.

A separate US survey of online households, released by the vendor in April this year shows that the number of bills paid electronically via the Internet now exceeds the number paid by paper cheques.