The rail is the cheapest part of a cross-border payment: where the cost actually goes

The payment rail is the cheapest part of a cross-border transfer. Wise's own unit economics, published in BIS Working Paper 1385 in October 2026, put the rail at £0.02 of a £0.24 fixed cost per GBP to EUR transfer. Customer support and compliance carried most of the rest. Cheaper rails help, but they are not where most of the money goes.

That matters for anyone pricing stablecoin payments, because most pitches focus on the on-chain hop. If you're new to how a stablecoin payment converts money at both ends, start with what a stablecoin sandwich is. For the paper's full findings, see what the BIS "competing rails" paper found.

Key takeaways

• Wise estimates a marginal cost of £0.24 plus 0.06% per GBP to EUR transfer.
• Of the £0.24 fixed cost, support is £0.11, compliance £0.06, other operations £0.05, and the rail £0.02.
• Blockchain gas fees are already tiny, so a faster or cheaper chain barely changes the total.
• Stablecoin cost estimates often leave out support and compliance, the two biggest fixed costs.
• Compare providers on delivered amount and on what the fee includes, not on the rail fee.

What does a cross-border transfer cost to run?

Wise put a number on it. Table 14 of the BIS paper lists the marginal cost of one GBP to EUR transfer, as provided by Wise in 2026.

Source: BIS Working Paper 1385, Table 14 (October 2026).

The paper's reading is direct: moving money across the rail is "among the least expensive components of the service." Support and compliance are the largest fixed costs.

How does that cost change with payment size?

The fixed part dominates small payments. The variable part dominates large ones.

Running the Table 14 numbers at two sizes (our arithmetic, not a figure from the paper):

A basis point is 0.01% of the amount. Two things stand out.

First, the per-payment cost of support and compliance is close to flat, so a £200 transfer carries three times the cost rate of a £10,000 one. That is why small payments cost more in percentage terms on every rail.

Second, at £10,000 the rail's variable 0.03% (£3.00) becomes about half the total. So the "rail is cheap" point is strongest for small and mid-size payments. For large tickets, FX and treasury cost matters again, which is why liquidity depth in your currency pair still decides the price on big payouts.

These are one firm's marginal costs in one deep corridor, not a price list. Prices to customers also include margin, risk, and the cost of thinner currencies.

Why are support and compliance the expensive parts?

Because people do them, every payment needs them, and the work doesn't shrink with the amount.

Compliance in cross-border payments covers KYC (verifying individuals), KYB (verifying businesses), sanctions screening against lists such as OFAC's sanctions lists, fraud controls, and ongoing transaction monitoring. Alerts need reviewers. Information requests need someone to write and read them. KYC vs KYB vs KYT breaks down what each check covers.

Support is the other half. A recipient asks where the money is. A bank rejects a name. A payment sits in review. Each of those is a ticket, and tickets cost more than gas.

In correspondent banking, the cost compounds. The BIS paper notes that AML/CFT checks "are often duplicated along the chain," and the Federal Reserve's March 2026 FEDS Note lists redundant compliance checks at multiple points in the chain as one of the costs of the intermediation model.

What does this mean for stablecoin payment costs?

It means the on-chain savings are real but small, and the expensive work doesn't disappear.

Stablecoins cut the cost of the transfer leg, which is one reason they come up in the G20 work on cheaper, faster payments tracked by the FSB targets for cross-border payments. The BIS paper finds average gas fees "well below one dollar" even on Ethereum, and a few cents or less on most other networks. But the rail was already the cheapest line. Replacing a £0.02 cost with a £0.01 cost doesn't change the economics of a £0.24 transfer.

What a stablecoin flow can change is the number of times the expensive work happens. One provider that runs KYC, KYB, screening, and monitoring once, inside the payment flow, avoids the duplicated checks of a multi-bank chain. That is a structural saving. A cheaper chain is not.

The paper also warns that support and compliance "are precisely the services that are often absent from estimates of the cost of a stablecoin sandwich." A cost model that counts only gas, exchange fees, and the FX spread is incomplete.

Which costs should you count when comparing providers?

All of them, including the ones a quote doesn't show as a line item.

The bottom four lines are where the BIS table says most of the cost sits. For the provider side of the same question, how on/off-ramp providers make money shows where each fee comes from.

What are the common mistakes when modeling cross-border payment cost?

Five come up again and again.

1. Counting only the rail. Gas or wire fees are a small share of the cost.
2. Using an average size. Fixed costs make small payments far more expensive in percentage terms. Model your real size distribution.
3. Ignoring the review queue. Payments that need information requests cost staff time on both sides.
4. Treating failure as free. A returned payment costs a retry, support time, and sometimes an FX loss.
5. Comparing headline fees. Compare the amount the recipient receives, measured at the same minute. Our cost per delivered dollar method walks through it.

How does BlindPay handle this?

BlindPay runs compliance inside the payment flow: KYC and KYB on customers through the API, and transaction monitoring on every payin and payout, so the checks happen once rather than at every hop. A payout quote locks the exchange rate and fees for a specific bank account, expires after 5 minutes, and shows the exact amount the recipient receives (payout quotes). BlindPay combines a monthly plan with per-transaction fees that vary by rail and network, disclosed in the live quote before execute. Payouts run over Pix, SPEI, ACH, RTP, SEPA, and SWIFT (POBO/COBO), with UETR tracking and MT103 confirmations on SWIFT.

What to do next

Pull last quarter's cross-border payments and split the cost into four buckets: rail and FX, compliance work, support tickets, and failed payments. If the last three are bigger than the first, which the Wise numbers suggest they are, focus your provider comparison there.