Key Takeaways
- Every transaction moves through merchant, processor, sponsor bank, and card networks
- Authorization and settlement are two separate steps
- The money you don't keep splits into interchange, assessments, and markup
- Only markup is negotiable
- Knowing the chain is how you read a statement and catch padded fees
Most merchants only see two things about card processing: the moment a card is tapped, and the deposit that lands in the bank the next morning. Everything in between is treated like plumbing — invisible until it breaks. The problem is that the invisible part is where the fees live, and you can't negotiate what you can't see.
The path a single transaction takes
A customer taps a card at your counter. The terminal sends that transaction to a processor. The processor routes it to the card network (Visa, Mastercard, Discover, Amex), which forwards it to the issuing bank — the bank that gave the customer the card in the first place. The issuing bank checks the account, approves or declines, and sends the answer back up the same chain. That whole loop happens in roughly two seconds.
That's authorization. Settlement is a separate event. At the end of the day (or whenever your terminal batches), the approved transactions are sent through for funding. The networks move money from the issuing bank to your sponsor bank, and your sponsor bank deposits funds into your account — typically next day on approved accounts, subject to processor rules.
The four parties who touch your money
- Merchant — you, the business accepting the card
- Processor — moves the transaction and carries the technology stack
- Sponsor bank — holds the regulatory relationship and carries risk
- Card networks and issuing banks — authorize the cardholder and move the funds
Merchant → Processor → Sponsor bank → Card networks and issuing bank. Money flows back the other direction, minus fees, usually the next business day.
Where the money goes
Every dollar in fees you pay splits into three buckets. Interchange goes to the issuing bank — it's the largest piece, set by the card networks, and it is not negotiable. Assessments go to the networks themselves — small, also not negotiable. Markup is what's left, and it's split between the processor and the ISO. Markup is the only number on your statement that can be moved.
When a salesperson promises to 'beat your rate by half a percent,' they're either cutting markup (legitimate), repricing your interchange categories (sometimes legitimate, sometimes a teaser), or quoting a number they can't actually deliver on (common). Understanding the three buckets is how you tell which is which.
Why the infrastructure matters
Bonita operates on Fiserv Direct processing infrastructure. That's what gives a New Orleans-based ISO national reach, modern card-present and card-not-present support, and next-day funding on approved accounts. The infrastructure is invisible to the merchant on a good day — and the only thing that matters on a bad one.
Why this matters for you
Once you understand the chain, you can read your statement. You can tell interchange from markup. You can spot a junk fee — the ones with names like 'network access,' 'regulatory compliance,' or 'PCI service' that don't map to any of the four parties above. And you can have a real conversation about what's negotiable instead of accepting whatever number a salesperson types into a proposal.
Elliott runs Bonita Payments from New Orleans. He writes General Quarters to share the playbook most ISOs would rather their agents and merchants never see — pricing math, residual structure, and what actually separates a partner from a vendor.