What is a pre-authorisation hold on a credit card?
A pre-authorisation hold on your credit card is not an actual debit. It's a request by the merchant for the amount to be held (similar to a pre-authorisation request for the amount of a purchase), pending the merchant processing a transaction for the amount of the pre-authorisation, or a lesser amount, on your card. This pre-authorisation guarantees that you have the funds available in your account to cover the final transaction amount.
For example, merchants may estimate the cost of your bill and ask you to provide a card as a guarantee. This amount may be larger than your final amount because the merchant wants to cover any potential losses (for example, if you damage a rental car). The real charge will go through after you complete the transaction.