The reward starts at the checkout
When a customer pays by credit card, the merchant usually pays a processing fee. Part of that fee—called interchange—goes to the bank that issued the card. The card network and payment processor take other portions. On a rewards card, the issuing bank can use some of its share to fund points, miles, or cash back.
That means the reward is not simply a bonus created by the card company. It is tied to a cost that appears whenever the card is used, including when the customer pays the bill in full and owes no interest.
How the cost reaches other shoppers
Merchants generally cannot know what every customer paid for a product and then adjust the price at the register to match that person’s payment method. Many instead build payment costs into prices across the store. As a result, customers paying with cash or a low-reward card may help cover costs generated by transactions on more expensive rewards cards, even though they receive little or nothing in return.
The size of that cross-subsidy varies. Merchants absorb some fees, and competition and local pricing rules shape whether costs are reflected in prices, surcharges, or other business decisions. It is not a precise dollar-for-dollar transfer from one shopper to another, but the shared-cost structure can favor people who spend more on premium cards.
Why issuers offer richer rewards
Rewards help banks attract customers who put substantial spending on their cards. Those customers generate more transaction revenue for the issuer; some also pay annual fees or interest, which can contribute to the card’s overall economics. The bank weighs those revenues against rewards and other costs, such as fraud and servicing.
So a wealthy cardholder’s points may be supported by several sources, but the checkout fee is a central link between everyday shopping and card rewards. The striking consequence is that the person earning the reward is not necessarily the only person paying for it.
