Card payments must be systematically authorized, meaning that the card will verify that the customer has enough money on the account set as the payment source at each payment attempt.
In very specific cases, described below, the account balance may become negative after using card (physical, contactless mobile payment or virtual card).
Cases in which an account balance becomes negative
When a payment is made in a place with very poor or no existent internet connection.
When a payment is made in an environment with poor or no internet connectivity, the transmission of the transaction may be delayed. If the customer makes one or more additional transactions in the meantime, the available balance may no longer be sufficient to cover the initial transaction, which can result in a negative balance.
When the final amount charged on the card is superior to the amount authorized.
This may happen, for example, when an individual takes the tube in London. When the customer passes her card at the tube entrance, a £1 authorization is debited. At the end of the trip, when the passenger passes a card again to exit the underground, the trip finally costs a total of £5. The authorized transaction will be updated with the right amount and force the debit even if the balance is insufficient in order to allow the passenger to leave the underground. As a result, this scenario could lead to overdraft.
This could also happen during a trip abroad due to exchange rates. If the exchange rate rises between the moment a transaction is made and when it is confirmed (which may take several days), a different amount may be charged and creates a negative account balance.
After several successive purchases, if a payment terminal hasn’t sent validation information for the transaction quickly enough.
The payment will still be made to the merchant, but if there are any technical difficulties in the information sent between the payment terminal and card networks, the authorized transaction, and hence the debit, might be delayed by a few minutes. If the customer makes other purchases in the meantime, it is possible that the account balance might be insufficient once the delayed transaction is finally debited. As a result, the account will become negative.
If a merchant takes a long time to send a positive (or negative) response regarding a transaction
The authorized transaction can be automatically reversed after 10 days if the merchant did not confirm it. If the merchant finally rectifies the situation and asks for a new debit because the original transaction was reversed, then the account balance can turn negative. Especially if the customer spent the money that got reversed initially. Learn more.
For any request related to a transaction that has resulted in a negative account balance, the customer may contact customer service.