The short answer
The Durbin Amendment is a section of the 2010 Dodd-Frank Wall Street Reform and Consumer Protection Act that did two important things for merchants: (1) capped the interchange fee banks with $10B+ in assets can charge on debit-card transactions, and (2) required that every debit transaction be routable over at least two unaffiliated networks so merchants can pick the cheaper one. Took effect October 2011. The cap is roughly $0.21 + 0.05% + a $0.01 fraud-prevention adjustment, compared to the pre-Durbin average of ~1.15% that was essentially uncapped.
What "regulated" vs "exempt" means
- Regulated debit: Issued by a bank with $10B+ in assets (Chase, BofA, Wells Fargo, Citi, most big names). Interchange capped at ~$0.21 + 0.05%.
- Exempt debit: Issued by credit unions and small community banks (under $10B). Interchange runs 1.0-1.5% — close to pre-Durbin levels. Your merchant statement will often separate these into two interchange categories.
- Prepaid debit: Prepaid cards are partially regulated with their own sub-cap.
The dual-routing requirement
Before Durbin, Visa-branded debit cards could only route over Visa's debit network. After Durbin, every debit card must be enabled on at least two unaffiliated networks (typically Visa/MC for the signature side, plus one of: Star, Pulse, NYCE, Maestro, Accel, Shazam on the PIN side). Merchants (or their processors) can steer debit transactions to the cheaper network — the savings on well-routed debit vs. default-routed can be 20-40 basis points.
What operators need to know
- Debit is your cheapest acceptance cost. A regulated-debit transaction costs $0.22 + change for interchange + assessments. A rewards-credit transaction costs 1.95% + $0.10. If your checkout flow encourages debit (or if your vertical skews cash-strapped), your effective rate drops meaningfully.
- Cash discount and dual pricing can't discriminate debit. You cannot surcharge debit ever, and cash-discount programs that effectively surcharge debit have been sued successfully.
- Debit routing is a quiet cost optimization. Ask your processor whether they're routing debit to the lowest-cost network or defaulting to Visa/MC. Many default because it's easier; many processors make more money on the default route.
- CFPB rule changes pending. The Federal Reserve in 2023-2024 proposed lowering the regulated-debit cap further (toward ~$0.14). As of 2026 the proposal is stalled but not dead. Watch the regulatory calendar.
- Debit isn't automatically good. Regulated-debit per-transaction is $0.22 — on a $3 ticket, that's 7%+. Debit favors medium-to-large tickets. Tiny-ticket verticals actually prefer credit.