Banks face an investigation from the Office of Fair Trading over their provision of current accounts to UK customers.
The OFT has launched a review saying it is "concerned that a lack of effective competition means the retail banking sector is not working in the interest of customers and businesses".
Banks are already under pressure to make it easier to switch accounts. They are working on a much faster and more reliable system of changing banks, after previous criticism from the Vickers Commission on banking.
The OFT will focus on account charges, greater customer control over accounts and easier account switching. It will report its findings at the end of the year.