Every so often we meet a vertical software or AI platform convinced that routing debit transactions through alternative networks like Star, Pulse, or Accel instead of the majors will unlock material interchange savings, a better spread, and more payments income.
That question got a lot more interesting last week. Reports surfaced that a consortium of mega-banks including JPMorgan, Bank of America, Wells Fargo, and PNC is exploring a bid for Fiserv’s STAR debit network, using the same playbook Capital One ran when it bought Discover. The logic: own the rail, and an expense becomes a revenue line. It’s a useful moment to revisit alt-debit routing, because it’s the same math we walk platforms through at a fraction of the scale. And mostly, it still doesn’t pencil out for them.
The thinking isn’t wrong. It’s just misguided.
The picture in my head is someone sprinting around a football field picking up scattered pennies while a neatly stacked pile of quarters sits untouched right in front of them. Yes, after collecting thousands of pennies they’ll have more money than they started with. They’ll also have far less than if they’d simply picked up the quarters.
Here’s why, and it requires some understanding of payments plumbing.
The Federal Reserve publishes debit interchange data split across “covered” and “exempt” transactions. Decoded: an exempt transaction is initiated with a debit card issued by a bank under $10B in assets. A covered transaction is one from a Durbin-regulated bank with more than $10B in assets. The good news: on an exempt transaction, alternative routing could save you around 35 cents (roughly 61¢ vs. 26¢). The bad news: on a covered transaction, your cost actually goes up about 2 cents (about 22¢ vs. 24¢).
Now apply that to the payment mix. Debit accounts for roughly 40% of card volume, with the rest being credit or charge. Of that debit volume, 67% is covered, issued by a large bank. So a platform doing $50M in monthly volume that could route intelligently to alternative networks, with identical authorization performance, would stand to generate roughly $[13,600] in savings against $400,000 in target payments income 2.7%, or 163,000 absolute dollars.
If you’re already lost, or you’ve concluded the juice isn’t worth the squeeze, good. Pick up the quarters and get back to growing your business.
If you’re still chasing pennies, keep reading, because the theoretical savings above wildly overstate the real yield.
Why the savings shrink in practice
Authorization performance is the big one. Many alternative-network debit auth requests will simply fail. You don’t want to lose the sale, so you retry on a backup alternative network, or back on a major. Every attempt costs money. If your auth performance degrades and you’re routing twice, the per-auth pricing eats the savings you were chasing.
Then there are PSP costs. Most processors charge a fee for least-cost-routing logic, which cuts directly into anything you save. And debit networks change pricing constantly, and ownership isn’t stable either. Fiserv currently owns Accel and Pulse, and as of this week is reportedly in talks to sell STAR to the very banks issuing your customers’ cards. If that deal closes, the rail your routing table depends on today could belong to a different owner, with different economics, tomorrow. Every time an alternative network adjusts pricing or changes hands, your routing table needs updating to figure out which transactions are still incrementally profitable to route around the majors.
The fact that JPMorgan, Bank of America, Wells Fargo, and PNC are willing to pay a large sum to own a debit rail tells you exactly who this strategy is built for: institutions issuing at a scale where a couple of basis points move billions.
Ignore the siren song of alternative-debit savings until you’re north of $5B in annualized gross payment volume. Below that, the quarters are right in front of you.
