Regulation II is the Federal Reserve Board rule that caps the interchange fee a covered debit card issuer can collect on a single electronic debit transaction. The cap is 21 cents plus 0.05 percent of the transaction's value, plus up to a 1-cent fraud-prevention adjustment, and it binds any issuer with, together with its affiliates, $10 billion or more in total assets. The rule has stood since the Board's implementing text took effect on July 20, 2011.
The cap sits at the center of a fee structure that most cardholders never see itemized, but that shapes how banks price checking accounts and how merchants set minimum purchase amounts. Under the Board's regulation, the amount is not a flat number so much as a formula, and the formula only reaches roughly six in ten debit transactions run in the United States. Payments teams on the merchant-acquiring side track this distinction closely, because it changes the economics of accepting a debit card long before any card network's own markup enters the calculation.
What Exactly Does the Fee Cap Limit, and Who Does It Bind?
The cap applies to any interchange fee a covered issuer receives for an electronic debit transaction, and the regulation defines it as the base 21-cent component plus an ad valorem component of 5 basis points of the transaction value, with an additional cent available only to issuers that meet the Board's fraud-prevention standards. On a $50 purchase, that formula works out to roughly 23.5 cents before the fraud adjustment — the base 21 cents plus 2.5 cents of ad valorem component.
The regulatory text requires that interchange fees be "reasonable and proportional to the cost incurred by the issuer with respect to the electronic debit transaction," a standard set out in the Board's rule at 12 CFR 235.3. That standard, not a single dollar figure, is the legal basis for the cap; the cents-and-basis-points formula is how the Board translated it into a number issuers and networks can apply transaction by transaction.
"Covered issuer" is the operative term. It means a bank, thrift, or credit union that, combined with its affiliates, reported total assets of $10 billion or more as of the prior December 31. Everyone below that line is exempt from the cap altogether, though not from the rest of Regulation II, including its network-routing requirements.
Which Issuers Are Exempt, and Why Do Their Fees Run Higher?
The small-issuer exemption under Section 920 of the Electronic Fund Transfer Act carves out any institution with less than $10 billion in combined assets, measured as of December 31 of the prior year. The Federal Reserve Board publishes and periodically updates the list of exempt and covered institutions; its most recent list, current as of December 31, 2025 asset data, was refreshed on May 27, 2026.
Because exempt issuers face no statutory cap, card networks continue to price their debit interchange on the same schedules used before Regulation II took effect, and those schedules run well above the covered-issuer cap. The Board's own transaction-level data make the gap explicit.
| Issuer status | Average interchange fee per transaction | Share of transaction volume |
|---|---|---|
| Covered (subject to the cap) | $0.23 | 60.7% |
| Exempt (small issuers) | $0.51 | 39.3% |
| All debit transactions, combined | $0.34 | 100% |
Those figures cover 2024, the most recent full year in the Board's published series. The 28-cent gap between covered and exempt averages is the practical measure of what the statutory cap actually removes from a transaction — and why community banks and credit unions, whose trade groups lobbied hard for the exemption, have generally opposed proposals to narrow it.
The exemption is not automatic relief for every small bank's customers, either. A merchant cannot tell from the card alone whether a given debit transaction will clear at the capped rate or the uncapped one; that depends entirely on the asset size of the cardholder's issuing institution, information the merchant does not see at the point of sale.
What Else Does Regulation II Require Beyond the Cap?
The fee cap is only one piece of the rule. Regulation II also sets routing requirements that apply regardless of an issuer's size:
- Every debit card must be enabled for at least two unaffiliated payment card networks, so a single network cannot be the only option for a given transaction type.
- Issuers and networks may not restrict which of those enabled networks a merchant can choose to route a transaction over.
- Networks and issuers may not inhibit a merchant's ability to direct the transaction to any network the card supports.
These routing provisions exist to give merchants a competitive choice of networks even where the fee cap does not apply, and they are enforced separately from the interchange fee standard itself. A small issuer exempt from the fee cap is still bound by the two-network routing mandate, which is why routing competition and fee-cap coverage are frequently confused but legally distinct questions.
Is the 21-Cent Cap Set to Change?
The Board proposed revising all three components of the cap for the first time since 2011 in a rule published in the Federal Register on November 14, 2023. As proposed, the base component would fall to 14.4 cents, the ad valorem component to 4 basis points, and the fraud-prevention adjustment would rise to 1.3 cents — a net reduction the Board's own analysis attributed to lower issuer costs measured through its biennial debit card issuer survey. The public comment period on that proposal closed February 12, 2024. As of this writing, the Board's regulatory text still reflects the original 2011 figures: 21 cents, 5 basis points, and a 1-cent fraud-prevention adjustment.
The proposal also included a mechanism for the Board to recalibrate the cap automatically every two years using survey data, rather than through a fresh notice-and-comment rulemaking each time. Whether and when that automatic-adjustment structure takes effect depends on the Board finalizing the pending rule, which had not occurred as of the proposal's most recently confirmed public status.
For issuers, a lower base component and ad valorem rate combined with a higher fraud-prevention adjustment is not a simple net gain or loss; the actual effect on any one bank's interchange revenue depends on that bank's transaction mix, average ticket size, and whether it currently qualifies for the fraud-prevention add-on at all.
What Should Merchants and Issuers Take From the Formula?
For a merchant evaluating processing costs, the operative fact is which category the customer's issuing bank falls into, not which network processed the card. A $40 debit purchase run through a covered issuer's card carries a materially different interchange cost than the same purchase run through an exempt community bank's card, even on the same network and terminal.
For issuers near the $10 billion threshold, the December 31 asset measurement date makes the exemption a planning variable as much as a regulatory classification — crossing the line converts every debit interchange dollar the bank collects from the exempt schedule to the capped one, with no phase-in period specified in the rule. That single balance-sheet date, more than any marketing decision or network agreement, is what ultimately determines which of the two columns in the Board's own fee table a bank's transactions land in.
None of this is guidance on how a merchant or issuer should price a product or structure an account; it is a description of what the published rule requires and what the Board's own data show it produces. Any operational decision built on top of these figures still depends on a business's own cost structure, contracts, and processing agreements, not on the cap alone.
For a related fintech news perspective, read Federal Reserve's Regulation II Caps Debit Interchange At 21 Cents.
