Some merchants, such as hotels, car rentals and restaurants, have a policy that requires them to pre-authorize and temporarily hold an amount of money from your card balance that is greater than your actual purchase amount. Once your purchase is processed by the merchant, your card balance will reflect the amount of your actual purchase and the held funds will become available for immediate use. Availability of the pre-authorized funds can take up to 10 days (90 days for car rentals) to be released back into your card balance.
In some instances, the initial pending transaction will not include the tip. Once your purchase is processed by the merchant, the tip will be included in the amount posted to the account.