A Pre-authorization hold is an additional amount that will be added to your pending transaction and dropped when your transaction actually posts. This is done to protect the merchant from fraud and loss, most notably applied at Hotels, Car Rental places, Gas Stations and Restaurants.
If you use any debit card at a gas pump that doesn’t require you to enter your PIN, a pre authorization of $75.00- $100 may occur. The amount is taken off your available balance. Gas merchants do this so they can be protected, meaning: the gas station doesn’t know how much a person will pump, so they earmark a larger amount to ensure a person’s account will cover what they pump. Some gas merchants, especially in Florida, do not warn consumers that a Pre-Authorization hold may be put on any debit account. The hold can last up to 72 hours or until the original transaction posts.
However, you can AVOID a Pre-Authorization hold by simply pre paying inside the store as debit. Use your PIN and the transaction will post immediately.
Additional Heads-ups: Most Gift Cards are run as Debit Cards.