Interchange Is Becoming a State-Level Knife Fight

For years, interchange lived in the part of payments that most software platforms preferred not to look at directly.

It was just there.

A mysterious line item. A cost of card acceptance. A processor pricing ingredient. A thing finance complained about, merchants resented, issuers defended, and software platforms usually tried to summarize with a phrase like “standard processing fees may apply.”

Elegant? No.

Convenient? Absolutely.

But that era is getting wobblier.

Illinois has pushed interchange into a new kind of fight with its Interchange Fee Prohibition Act, a law aimed at preventing interchange fees from being charged on the tax and gratuity portions of card transactions. The law’s effective date was pushed to July 1, 2026, after originally being scheduled for 2025. In February 2026, a federal district court partially upheld the law’s prohibition on charging interchange on state and local taxes and gratuities, while enjoining certain data-use restrictions. Then in April 2026, the OCC issued an interim final rule and order intended to preempt the Illinois law for national banks, adding another layer of legal uncertainty right before the effective date.

So yes, this is a legal fight.

But it is not only a legal fight.

It is also a product fight, a pricing fight, a data fight, a point-of-sale fight, a reconciliation fight, a merchant-experience fight, and a “who exactly owns this mess?” fight.

In other words, it is payments.

Interchange Used to Feel National. Now It Feels Local.

One of the strange comforts of card payments is that, despite all the complexity underneath, the system mostly feels national.

A card works in Illinois. A card works in Texas. A card works in Florida. A card works online. There are differences in taxes, surcharging rules, consumer protection laws, industry restrictions, and disclosure requirements, but the basic mental model has been fairly consistent: a card transaction runs through the card system, fees are assessed, funds move, reports arrive, everyone argues about the cost later.

The Illinois law challenges that comfort.

By targeting interchange on specific components of a transaction — taxes and tips — the law forces a question the card ecosystem has not historically been designed to answer at scale in the same way across every state:

Which part of this transaction is actually the merchant’s sale, which part is tax, which part is gratuity, and which parts should or should not carry interchange?

That sounds simple until you remember how payments systems actually work.

At the point of sale, tax and tip information may exist. In restaurant environments, tips may be added after authorization. In ecommerce, tax calculations may be handled by one system, payment authorization by another, and settlement reporting by another. In marketplaces, platform fees, seller proceeds, shipping, taxes, service fees, discounts, coupons, and tips may all be part of one customer-facing total but several different economic realities underneath.

The payment system has always cared about the total amount.

Now states are asking it to care more about the anatomy of the total.

That is a much bigger deal than it sounds.

The Fight Is Not Really About Pennies

The merchant argument is straightforward: why should a business pay interchange on money it does not keep?

If a retailer collects sales tax and remits it to the government, that tax is not revenue. If a restaurant collects a gratuity for staff, that tip is not the restaurant’s sale in the same way as the meal. From the merchant’s perspective, paying interchange on those portions feels like paying a toll on money passing through their hands.

That argument has political appeal because it is easy to understand.

The banking and card-industry response is also predictable: card systems are national, complex, and expensive to operate. Interchange helps fund issuing, fraud protection, rewards, credit availability, dispute handling, authorization infrastructure, and network economics. If every state starts carving up card transactions differently, the operational burden could become chaotic, especially for issuers, processors, networks, acquirers, and merchants operating across state lines.

Both sides can make a case.

That is what makes the fight durable.

Merchants see unfair cost allocation. Banks see system fragmentation. Networks see rule complexity. Processors see implementation headaches. Platforms see another place where “payments pricing” stops being a simple line in the commercial model and starts becoming a cross-functional fire drill.

The dollar amounts matter, obviously.

But the deeper issue is control.

Who gets to decide how payment economics are allocated? Federal regulators? States? Card networks? Banks? Merchants? Processors? Platforms? Courts?

If the answer becomes “all of the above, depending on where the transaction happens and who issued the card,” then everyone should cancel their clean roadmap slides.

Software Platforms Are Not Spectators

A lot of software platforms may look at the Illinois interchange fight and assume it belongs to banks, card networks, processors, and large retailers.

That is the first mistake.

If your platform helps merchants accept card payments, build checkout flows, calculate taxes, prompt for tips, route transactions, reconcile settlements, manage reporting, support refunds, or explain processing costs, you are closer to this fight than you think.

Maybe you do not set interchange.

Maybe you do not receive interchange.

Maybe your processor handles most of the card economics behind the scenes.

Cute.

Your customer still sees your platform.

If a merchant’s effective rate changes, they will ask you why. If tax and tip treatment changes by state, they will ask whether your platform supports it. If reporting needs to break out tax, gratuity, fees, and sale amount differently, finance will ask product for better data. If a processor changes pricing, settlement files, or reporting logic, your operations team will have to explain it. If a restaurant customer wants to know why tips are treated differently in one state than another, support will not be able to forward them a law-review article and call it a day.

Payments regulation has a habit of landing on whoever owns the user interface.

That is the platform.

The Data Problem Is the Product Problem

This is where the Illinois law gets especially interesting for software companies.

To avoid interchange on taxes and tips, someone needs to know what portion of a transaction is tax and what portion is gratuity. That data needs to be captured, transmitted, understood, reported, and possibly validated across different players in the payments chain.

That sounds like a compliance detail.

It is actually a product architecture question.

Where does tax get calculated? Where is tip captured? Is the tip known at authorization or adjusted later? Does the payment processor receive a clean breakdown? Does the gateway support the right fields? Does the platform store the breakdown in its own ledger? Can the merchant report on it? Can finance reconcile it? Can support explain it? Can the processor pass it downstream? Can the network handle it? Can the issuer see it? Can the platform prove what happened if someone asks?

Those questions are not limited to Illinois.

They are the kind of questions platforms should already be asking about payment data generally.

Too many platforms treat transaction data as a receipt artifact rather than operational infrastructure. They know the total amount, maybe the processor fee, maybe the payout, maybe the refund. But when the world starts asking more precise questions — what was tax, what was tip, what was fee, what was merchant revenue, what was platform revenue, what was seller proceeds, what was retained, what was refunded — the system starts sweating.

A law about interchange can suddenly expose a data model that was never designed to understand the transaction it processed.

That is awkward.

It is also common.

State-by-State Payment Economics Are a Nightmare With Good Intentions

The Illinois law may be the first of its kind, but it is not happening in a vacuum. Similar proposals have appeared in other states, creating the possibility of a broader state-level battle over interchange.

That is where the operational stakes rise.

One state rule is hard.

Fifteen different state approaches would be a migraine with statutory citations.

Platforms operating nationally would need to understand where the merchant is located, where the buyer is located, where the transaction occurs, which law applies, which card type is involved, whether the issuer is covered, whether the acquirer is covered, whether federal preemption applies, what the processor supports, what the merchant contract says, and how all of that maps into pricing and reporting.

That is before someone asks about refunds.

Imagine refunding a transaction that included taxable items, non-taxable items, a tip, a platform fee, a discount, and a partial return, in a state where tax-and-tip interchange treatment differs from the state next door.

Now imagine explaining the fee math to a merchant who simply wants to know why their statement changed.

This is why payments people age in processor years.

The policy goal may be simple: reduce fees on money merchants do not keep. But the implementation lives inside systems that were not necessarily built for fifty versions of fee treatment.

Good intentions do not eliminate operational complexity.

They usually create a ticket for it.

The OCC Move Does Not Make This Go Away

The OCC’s April 2026 interim final rule and order aimed to preempt the Illinois law for national banks, and banking-industry supporters have argued that federal preemption is necessary to avoid fragmented state regulation of national card systems. Retail advocates have pushed the other direction, arguing that Illinois is targeting a real merchant cost and acting within state authority.

That means the practical answer is not settled in the way operators prefer answers to be settled.

There is litigation. There is preemption. There are state interests. There are federal banking arguments. There are merchant economics. There are issuer economics. There are implementation concerns.

For platforms, the dangerous move is to interpret uncertainty as permission to ignore the issue.

That is how companies get surprised.

The better move is to treat the fight as an early warning about where payment economics may be headed. Whether the Illinois law survives intact, gets narrowed, gets preempted, or inspires other versions elsewhere, the message is clear: interchange is no longer just a card-network economics topic. It is becoming a state-policy target.

Once an issue becomes politically legible, it rarely goes quietly back into the processor statement.

What Platforms Should Be Asking Now

Most platforms do not need to panic.

Panic is not a strategy. It is just poor planning with more meetings.

But platforms should start asking better questions, especially if they serve merchants in retail, restaurants, services, hospitality, marketplaces, field services, or any environment where tax, tip, fees, and card acceptance costs matter.

Start here:

• Can our system distinguish sale amount, tax, gratuity, platform fee, shipping, discount, and other components?
• Does our processor or gateway receive that breakdown today?
• Can our ledger preserve it through settlement, refunds, chargebacks, and reporting?
• Do our merchant statements clearly explain fees and deductions?
• Can we support state-specific payment logic without hard-coding chaos?
• Who monitors state-level payments regulation: legal, compliance, product, finance, or nobody until a customer asks?
• What does our payments partner plan to do if state interchange rules expand?
• Can support explain payment pricing changes without accidentally making legal claims?
• Are our contracts flexible enough to handle regulatory or network-driven pricing changes?

That last one matters.

If your commercial model assumes payment fees work the same way everywhere forever, your commercial model may be lying to you.

The Customer Experience Will Get Weird First

Before this becomes a clean legal conclusion, it may become a messy customer experience.

Merchants may hear about “no swipe fees on taxes and tips” and expect savings. Processors may issue updates that are technically accurate but difficult to understand. Banks may warn of disruption. Retail groups may tell merchants one thing. Trade associations may tell them another. Courts and regulators may change the timeline. Sales teams may overpromise. Support teams may be underprepared.

The merchant will ask a simple question:

“What does this mean for me?”

Platforms need a better answer than “ask your processor.”

Sometimes that answer is valid. Often it is also insufficient.

A strong platform answer might say:

Here is what we know. Here is what is still being litigated or clarified. Here is what our payment partner has told us. Here is what our system currently supports. Here is what may change in reporting or pricing. Here is where to find official guidance. Here is what we cannot advise on.

That is not legal advice.

That is adult communication.

Customers do not expect platforms to control every regulator, court, network, or bank. They do expect the platform handling their payments experience to know what is going on.

This Is Bigger Than Illinois

The Illinois fight is interesting because it is specific.

Taxes. Tips. Interchange. July 1, 2026. OCC preemption. Litigation. Merchant groups. Banking groups.

But the broader story is more important: payments economics are becoming more exposed to political pressure, merchant frustration, and state-level experimentation.

That creates a new kind of operating environment for platforms.

Pricing can no longer be treated as a static processor schedule. Data breakdowns can no longer be an afterthought. State-level rules can no longer be ignored by national platforms. Customer messaging can no longer be delegated entirely to the payment provider. Contracts need room for regulatory change. Product teams need to understand that fee treatment may depend on transaction composition, geography, card type, and partner capability.

This is what happens when a cost structure becomes visible enough for lawmakers to touch.

The platform does not need to take a side in every interchange fight.

But it does need to understand what happens when the fight reaches the product.

The Takeaway

Interchange used to feel like background noise.

Not anymore.

The Illinois tax-and-tip fight is a warning that payment economics are becoming more fragmented, more political, and more operationally demanding. Whether the law survives exactly as written or changes through litigation and federal preemption, the direction is clear: merchants, banks, regulators, networks, and states are fighting over pieces of the transaction that platforms may not even be tracking cleanly.

That should make software companies nervous in a productive way.

Because if your platform cannot identify tax, tip, fees, merchant revenue, platform revenue, refunds, disputes, and settlement outcomes clearly, you are going to struggle in a world where those components matter more.

The future of payments pricing may not be one clean national argument.

It may be fifty smaller fights with different rules, timelines, lawsuits, and implementation headaches.

So yes, interchange is becoming a state-level knife fight.

The smart platforms will not wait until someone hands them the knife to figure out where their transaction data lives.

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