Credit card transactions are usually split into two stages: Authorize and Capture. An authorization doesn't necessarily mean the transaction is finalized — the payment is only completed once Capture happens. Once your transaction volume gets large enough in the U.S., payment processors track your "completion rate". You can't keep collecting authorizations and then refunding because of stockouts. If your refund rate is too high, processors don't earn their fees, and they end up wasting time reconciling bad transactions with the banks. Payment processors typically have rules: if you exceed a certain refund rate, they may report it to the issuing card networks, which can affect your Visa privileges and even cause a temporary suspension. That's why U.S. B2C e-commerce sites usually only Authorize the card at checkout and hold the authorization until the order ships, only then performing Capture. But because most American consumers' credit limits hover around $8,000, anything above that gets captured up front to avoid running out of available limit.