A computer apparatus for performing financial transaction processing on a plurality of accounts is disclosed. The computer apparatus comprises a data storage device having a plurality of account files, each account file storing data relating to a particular account; a data processor for processing data relating to the account files; an input for receiving data relating to the account files and an output for outputting data relating to the account files. The input is arranged to receive data relating to debits and credits for particular account files which are processed by the data processor and stored in the corresponding account files on the data storage device. The data processor is arranged such that an account holder may have the file for their account on the data storage device marked with an indicator for activation of assistance when the account holder for that particular account file has committed expenditure which is greater than income.