It is well known that banks in England did not publish their 'true' profits until 1969. This article discusses the problems encountered in establishing the banks' 'true' profits and capital for earlier periods from their published accounts and unpublished archival sources. Definitions of profits and capital are considered and the methods used by the authors elsewhere in the calculation of true profits, capital, and rates of return are described. A number of areas causing particular difficulty are identified and discussed in detail. The accounting practices followed by the banks are compared to more generally-used financial accounting practices.