The main card and the auxiliary card share an account, and the transaction details of the auxiliary card are listed on the statement of the main card, which is convenient for the cardholder of the main card to master the usage of the auxiliary card. The consumption, cash withdrawal and other transactions of the secondary card and the corresponding handling fees are all collected in the main card account.

Generally speaking, the supplementary card enjoys the same credit limit as the main card, and the cardholder of the main card can also set a credit limit lower than that of the main card for the supplementary card alone. If you want to increase the usage limit of the secondary card, the cardholder can deposit a certain amount of money in the main card in advance (the money does not pay interest) and call the bank. At this point, the limit of the secondary card is the original maximum limit plus the deposited funds.

In this case, after the primary card is cancelled, the secondary card cannot be used.