When using your card at certain locations, such as restaurants, hotels, or other venues that often include a tip or surcharge, merchants may add in a tolerance amount – a preauthorization of up to 20% or more - so please ensure you have sufficient funds on the card.
Example: If your total bill at a restaurant is $50, the card may be preauthorized for $50 + 20%. Although you will only be charged for the actual total that is signed for, you will need an available balance of at least $60 on the card for the transaction to be approved. If your total, after adding in the tolerance amount, exceeds the balance on the card, the transaction will be declined.