How Do Credit Cards Make Money on Cash Back Rewards?

Credit card companies make money on cash back rewards because the rebate they pay you is only one line in a much larger ledger. Every swipe generates a merchant fee that comfortably exceeds the 1% or 2% you get back. On top of that margin, issuers collect interest from the roughly half of cardholders who carry a balance, annual and penalty fees from almost everyone, and quiet income from rewards that go unredeemed and from the transaction data your spending produces. The rebate is real, but it’s a small share of what the card earns.

The Merchant Fee Behind Every Swipe

When you pay with a credit card, the merchant’s bank pays an interchange fee to your issuing bank before the merchant collects the sale. On the Visa network, interchange ranges from roughly 1.15% to 3.15% of the transaction, plus a small per-swipe charge.¹ Mastercard’s published range is comparable, generally between about 1.43% and 2.60% depending on the card tier and merchant category.² American Express charges merchants more, from about 1.43% to 3.30%, which is one reason some smaller businesses still refuse it.

Premium cash back and rewards cards sit at the top of these ranges by design. Mastercard’s schedule shows its entry-level Core cards charging merchants about 1.65% on a standard purchase, while its top-tier World Elite cards charge 2.30% on the same transaction.² That 0.65-point gap is the room the bank uses to hand you 1.5% or 2% back and still clear a profit on the sale itself.

The per-transaction math is modest. On a $100 grocery purchase, the bank might collect $2.10 in interchange and pay you $1.50 back, keeping about 60 cents. Multiply that across millions of accounts swiping thousands of times a month, and interchange becomes the baseline that makes any cash back program viable.

Interest on the Balances People Carry

Interest is where issuers earn far more than they ever pay out in rewards. Close to half of cardholders carry a balance from one month to the next, and the average APR across all cards sits around 24% to 25% as of early 2026, with individual rates running from the low teens to nearly 35%.³

The link between rewards and interest income isn’t a coincidence. Cards that pay 3% on dining or 5% on groceries push you to route more of your spending through plastic. Higher spending raises the odds that something eventually gets carried, especially in a tight month. A Federal Reserve study found credit card interest and fees together generated $99.6 billion, while issuers spent $34.8 billion on rewards during the same period.⁴ The gap between those two numbers is the answer to the question.

The practical takeaway: a cash back card is only a net gain to you if you pay the statement balance in full every month. Carry a balance for a single cycle, and the interest usually swallows a year’s worth of rewards.

Annual Fees and Penalty Charges

Direct fees are the next layer. Many of the most generous cash back cards charge annual fees, from around $95 to $695 or $795 on premium travel-and-rewards cards. The issuer is betting that a predictable yearly charge will outpace what most cardholders actually earn and redeem in rewards.

Late payments add another stream. Federal regulations let issuers charge penalty fees under safe harbor thresholds set by the CFPB, which currently sit at about $30 for a first late payment and $41 for a second late payment within the next six billing cycles.⁵ A 2024 CFPB rule that would have cut the safe harbor to $8 for large issuers has been stayed by a court injunction and is not in effect, so the higher amounts remain the industry standard.³

Balance transfers typically cost 3% to 5% of the amount moved, and foreign transaction fees generally run 1% to 3% of each purchase made abroad or with an international merchant, though some issuers waive the foreign fee as a competitive perk.

Rewards You Earn but Never Use

Not every dollar of promised cash back ever leaves the bank. The industry calls it breakage. The CFPB found that issuers forfeit, expire, revoke, or otherwise take away hundreds of millions of dollars in earned rewards each year, and about 4% of all accountholders lose access to some of their rewards in any given quarter.⁶

The common ways rewards disappear:

Closing the account, by you or by the issuer, usually wipes out unredeemed cash back, though some issuers allow a short grace period to cash out.
Missing a minimum payment can let the issuer withhold rewards earned that cycle. Some will reinstate them after you pay, sometimes charging a reinstatement fee.
Extended inactivity can trigger an account closure that voids the balance of accumulated rewards.

Every forfeited dollar is pure profit. Rewards sit on the issuer’s books as a liability, and when they expire that liability reverses straight into earnings. Advertising generous earning rates attracts high-spending customers while a meaningful share of what’s earned is quietly reclaimed.

Selling the Data Your Spending Generates

Your transactions themselves have value. Where you shop, how much you spend, when, and how those patterns shift over time add up to a dataset the card networks package and sell. Networks have built dedicated business units around aggregated and anonymized transaction data, selling it to advertisers, hedge funds, and retailers. One network alone advertises access to billions of purchase transactions through more than two dozen data products. None of this shows on your statement, but it’s one more reason the issuer wants your card used often.

Who Actually Pays for the Rewards

The cost of cash back doesn’t stop at the issuer and the merchant. Retailers paying 2% or more in interchange on card sales bake those costs into shelf prices, so a customer paying with cash or a debit card pays the same inflated price and gets nothing back. Federal Reserve researchers estimated an annualized $15.1 billion redistribution flowing from non-rewards consumers to rewards cardholders through this mechanism, and found the transfer tends to be regressive, moving money from lower-income consumers who are more likely to use cash or debit toward higher-income consumers holding premium cards.⁴

Merchants can push some of that back. Federal law lets businesses add a credit card surcharge to recoup fees, capped at 4% under the major networks’ rules and subject to disclosure at the point of entry and on receipts.⁷ Surcharges can’t be applied to debit or prepaid card purchases, and some states restrict or ban them entirely, though cash discounts are permitted everywhere.

Do You Owe Tax on Cash Back?

Cash back earned from purchases is not taxable income. The IRS treats spending-based credit card rewards as a rebate on the purchase price rather than new income, so $2 back on a $100 purchase is treated as though you paid $98.⁸ No 1099, nothing to report.

Sign-up bonuses follow the same rule as long as they require you to spend a minimum first. A “$200 after spending $500 in three months” offer is still tied to purchases and is treated as a rebate. The line shifts when a reward has no spending requirement. A bonus paid simply for opening an account, or a referral bonus for sending a friend to the issuer, counts as taxable income because no purchase triggered it, and if it crosses the reporting threshold the issuer will send a 1099-MISC or 1099-INT.

1
Visa. Visa USA Interchange Reimbursement Fees
2
Mastercard. Mastercard 2025-2026 U.S. Region Interchange Programs and Rates
3
Consumer Financial Protection Bureau. Credit Card Penalty Fees Final Rule
4
Federal Reserve Board. Who Pays For Your Rewards? Redistribution in the Credit Card Market
5
Federal Register. Credit Card Penalty Fees (Regulation Z)
6
Consumer Financial Protection Bureau. Credit Card Rewards Issue Spotlight
7
Mastercard. What Merchant Surcharge Rules Mean to You
8
Internal Revenue Service. PLR-141607-09