1. A data processing system for managing and producing statements for a credit card account of a cardholder, comprising: first means provided at points of purchase for entering charge data including data identifying one or more sub-accounts, designated by the cardholder, to which charged transactions are to be allocated; second means for processing data for said credit card account including each of said designated sub-accounts; third means for storing said data on a storage medium; fourth means for processing said data, said processing including: (i) allocating said charged transactions to said one or more designated sub-accounts; and (ii) allocating interest accruals among said one or more designated sub-accounts to which said interest accruals are attributable; fifth means for processing said data, said processing including allocating payments made by the cardholder to said one or more designated sub-accounts; and sixth means for processing periodic statements, said processing including: (i) calculating said charged transactions, said interest accruals, and said payments made by the cardholder; (ii) allocating said calculated charged transactions, said calculated interest accruals and said calculated payments to said one or more designated sub-accounts; and (iii) generating the periodic statements including a report showing said calculated charged transactions, said calculated interest accruals, and said calculated payments on both a sub-account basis and a cumulative basis for the credit card account.