The short answer The Durbin Amendment caps the debit interchange fees big banks can charge and guarantees merchants a choice of at least two unaffiliated debit networks — yet most small businesses never see the benefit. If you pay a flat rate (like 2.9% + 30¢) on debit, or your processor never turned on least-cost routing, you are almost certainly overpaying on debit-card transactions that federal rules capped at roughly 22¢ each. Fixing it is a pricing-and-routing question, not a rate you have to accept.
Debit is quietly one of the most mispriced lines in American payment processing. A federal law has capped what large banks can charge on it since 2011 — but the savings only reach the merchant if pricing and routing are set up to pass them through. For most SMBs, they aren't. Here is how the Durbin Amendment actually works, and where the money leaks.
What is the Durbin Amendment, in plain terms?
The Durbin Amendment is a provision of the 2010 Dodd-Frank Wall Street Reform and Consumer Protection Act, named for Senator Dick Durbin. It directed the Federal Reserve to regulate debit-card interchange — the per-transaction fee a card-issuing bank collects every time you accept a debit card. The Fed implemented it through Regulation II.
It does two separate things, and confusing them is where merchants lose money:
- A fee cap on debit interchange for large issuers.
- A routing mandate giving merchants a choice of debit networks on every debit card.
How much can a bank charge for a debit transaction?
For a regulated issuer — a bank or credit union with $10 billion or more in assets — Regulation II caps debit interchange at 21 cents plus 0.05% of the transaction, plus a 1-cent fraud-prevention adjustment for eligible issuers. On a typical ticket that lands near 22¢ total, whether the sale is $18 or $180. That flat, near-fixed cost is the single most important number in this whole topic.
Cards from exempt issuers (under $10B in assets) aren't capped, so their debit interchange runs higher — often closer to unregulated levels. But — and this is the part most merchants miss — the routing right below applies to all debit cards, capped or not.
Why might my debit fees be wrong right now?
Because the cap protects the bank's maximum, not your price. Three common setups quietly eat the savings:
- Flat-rate pricing. Processors that bill one blended rate (e.g., 2.9% + 30¢) charge that on a debit sale even though the true interchange cost was capped near 22¢. You pay credit-card economics on a fee-capped instrument.
- No least-cost routing. Every debit card runs on at least two unaffiliated networks — a global brand like Visa or Mastercard, plus a domestic debit network such as Star, Pulse, NYCE, Accel, or Shazam. If routing isn't optimized, transactions default to the pricier path.
- Downgrades and miscategorization. Debit that isn't passed through cleanly gets re-qualified into more expensive buckets, especially on card-not-present sales.
What changed for online payments in 2023?
Originally the two-network routing choice was clear for in-person swipes but ambiguous online. In October 2022 the Federal Reserve finalized amendments to Regulation II clarifying that the prohibition on network exclusivity also applies to card-not-present transactions — e-commerce, subscriptions, invoicing. That rule took effect July 1, 2023.
Translation: banks must now enable two unaffiliated networks for online debit too, so merchants and their processors can route those transactions to the lower-cost option. If your e-commerce or recurring-billing stack was configured before mid-2023 and hasn't been revisited, it may still route every online debit down the default path.
Is the Durbin cap going away?
It's contested, which is exactly why this deserves attention now. In October 2023 the Fed proposed lowering the cap (a 14.4¢ base, 4.0 basis points, and a 1.3¢ fraud adjustment); that proposal has not been finalized. Then in August 2025, in Corner Post, Inc. v. Board of Governors of the Federal Reserve System, a federal district court in North Dakota held the Fed exceeded its authority and vacated Regulation II's interchange standard — while staying that ruling pending appeal to the Eighth Circuit so debit doesn't become a wholly unregulated market overnight.
How do the pricing models compare on debit?
The clearest way to see the leak is to price the same debit sale two ways. Below is an illustrative $45 debit transaction.
| Pricing model | What you pay on a $45 debit sale | Who keeps the Durbin savings |
|---|---|---|
| Flat / blended (2.9% + 30¢) | ~$1.61 | The processor |
| Tiered ("qualified" buckets) | Varies — debit often downgraded | Usually the processor |
| Interchange-plus + least-cost routing | ~$0.35–$0.45 | You |
Illustrative sample for explanation only — not a quote or a verified client outcome. Actual interchange, network fees, and processor markups vary by card, issuer, ticket size, and routing configuration.
What would this look like for a real business?
Consider a representative composite home-services company — think a regional HVAC and plumbing operator — running about $200,000/month in card volume, roughly 40% of it on debit at a ~$45 average ticket. On flat-rate pricing, that debit slice costs meaningfully more than the same volume on interchange-plus with routing tuned to the capped debit path. In a scenario like this, the modeled gap runs into the low-thousands of dollars per month — margin that was sitting in the routing configuration the whole time.
Representative composite SMB, illustrative results — not a specific real client, and not a guarantee. Savings depend entirely on your current setup.
What should I actually do about it?
- Find out how you're priced. Flat, tiered, or interchange-plus — it's on your statement, sometimes buried.
- Check whether least-cost routing is on for both in-person and online debit.
- Look for debit downgrades — regulated debit that isn't clearing at the capped rate is a red flag.
- Re-audit anything built before July 2023, when online routing choice became mandatory.
This is precisely the kind of overlooked, unglamorous margin Apex Pay was built to surface — reading your statements line by line and modeling what your debit should cost, not what you've been trained to accept.
Frequently asked questions
Does the Durbin Amendment apply to credit cards?
No. The interchange cap and the debit routing mandate apply only to debit cards (and certain prepaid cards). Credit-card interchange is not capped by Durbin.
Does the cap apply to every debit card I accept?
The fee cap applies only to cards issued by regulated banks with $10 billion or more in assets. Cards from smaller, exempt issuers aren't capped — but the routing choice (at least two unaffiliated networks) applies to all debit cards, so you can still route to the lower-cost option.
What is least-cost routing?
Least-cost routing is choosing, per debit transaction, the cheaper of the enabled unaffiliated networks. Regulation II guarantees the choice; your processor and gateway have to actually enable and exercise it.
Will lowering my debit costs hurt my approval rates?
Generally no. Routing debit to a lower-cost network is about which rails the transaction travels, not about declining more sales. Done well, cost optimization and healthy approval rates coexist — poor configuration can hurt both, which is why an audit matters.
Is the Durbin debit cap still in effect in 2026?
Yes, as of this writing the cap remains in force. A 2025 court ruling vacated Regulation II's interchange standard but stayed that decision pending appeal, and a separate Fed proposal to lower the cap is not final. The rules are stable today but genuinely in flux, which is a reason to lock in debit-friendly pricing now.