Wachovia, the fourth largest US bank by assets, has stripped the chairmanship from Ken Thompson but left him as chief executive following big loan losses and regulatory problems.

The move to install Lanty Smith as non-executive chairman of the board came two days after Charlotte-based Wachovia nearly doubled the size of its first-quarter loss to $708m after adding $315m in writedowns on the value of life assurance policies it takes out on its own employees.