What is a pre-authorisation hold on a debit/credit card?
When you use your debit or credit card to conduct an online or payWave transaction, the merchant electronically sends your bank a pre-authorisation request for the amount of your purchase.
This amount is placed on ‘hold’ but not actually debited from your account immediately, and the available balance in your account is reduced by the amount of the purchase. The amount is kept on hold/locked for up to four days, until the transaction is settled and the funds are debited (taken) by the merchant's bank.
When you select savings and you enter a PIN, the amount of the transaction is usually immediately deducted from your bank account and is not placed on hold first.