Pending Authorization

• If you use your credit card to buy something, the transaction doesn't show up on your statement right away. However, the financial institution holds the amount of the purchase against your available credit. A pending authorization hold is placed on your card for the balance in order to verify that your card is valid and that your credit card has enough room to cover the purchase.
  
  

Transaction Processing

• The authorization hold is present for the duration of the time spent processing the transaction. In most cases, transactions process in three days or less, and you end up being charged the same amount as the pending authorization hold. Once the transaction is processed, you'll finally be able to see it if you check your account online, and your card's balance will be accurate.
  
  

Exceptions

• In most cases, pending authorizations come and go without ever requiring your attention. However, sometimes authorizations cost less or more than the items your purchase. For example, hotels may put an authorization hold greater than the cost of your room in order to verify that your card is good for incidental charges, room service or pay-per-view movies. In the case of gas, an authorization could go either way; you may get charged just $1 initially, or the retailer may place a hold well in excess of what you purchased. Lastly, if you allow your card to exceed its limit to cover the cost of a purchase, you'll likely be charged an over-limit fee in addition to the amount of the transaction.
  
  

Refunds

• Credit card refunds work in a similar fashion to credit card purchases in that the financial institution finalizes the refund a few days after the merchant requests a refund to your account. However, there isn't a pending authorization hold, so you usually don't see the refund impact your available credit until the transaction posts. This can be particularly frustrating if you're using a debit card as a credit card. If you have trouble returning an item purchased with your credit card, check with your credit card company; most cards offer protection to those customers having difficulty returning purchases.