An outstanding debit card authorization is the amount immediately deducted from your available balance while the Credit Union waits for the final settlement request from the merchant, which can take several days. A final settlement request is an instruction from the merchant to the Credit Union to deduct the exact amount of your final purchase. It follows after the debit card authorization request and completes the transaction.
While the majority of transactions are settled within two to three business days, the actual timing rests with the merchant and is out of the control of the Credit Union.
Keep in mind, until the final settlement, the outstanding authorization amount may be larger or smaller than your actual purchase amount. In some cases when final settlement is delayed, the outstanding authorization is released, which causes your available balance to appear larger than you might otherwise expect.