The Quiet Leak: DCC, Settlement Currency and FX Spreads in Offshore Card Processing

Most UK merchants compare offshore card processing on the headline rate. That is understandable: it is the number presented first. But a cross-border transaction can pass through several currency conversions before it reaches the company bank account, and each conversion may carry a margin. Dynamic currency conversion, settlement-currency choice and FX spread markups can quietly reduce the net value of overseas sales. A treasurer-style review of the full cost stack is often more valuable than a narrow rate negotiation.

Four conversions, one transaction

A single overseas card payment can involve the cardholder's currency, the transaction currency, the settlement currency and the merchant's payout currency. The cardholder may be offered dynamic currency conversion at checkout. The acquirer may settle to the merchant in a chosen currency. The merchant's bank may then convert that settlement currency into sterling for working capital. Each step has a rate, a timing convention and sometimes a fixed fee.

The cost is not always visible on the processing statement. DCC revenue may be shared between parties, FX spreads may be embedded in the exchange rate rather than shown as a line item, and chargebacks may be converted at a different rate from the original sale. UK directors should ask for a statement that separates scheme fees, processing fees, DCC participation, FX margin and chargeback conversion.

DCC is not free money

Dynamic currency conversion allows a cardholder to pay in their home currency when shopping with a merchant that prices in another currency. For the cardholder, it offers certainty at the point of sale. For the merchant, it can affect approval rates, dispute behaviour and revenue share. Some acquirers offer merchants a share of the DCC margin; others apply DCC automatically under certain configurations.

The key question is who bears the conversion and at what rate. If a UK merchant sells in euros and the cardholder chooses to pay in sterling through DCC, the merchant may still settle in euros or sterling depending on the contract. A DCC margin of 3% on a transaction is not a 3% gain to the merchant unless the merchant receives the whole margin. Often the merchant receives only a share, while the cardholder pays the full markup. Merchants should model DCC as a commercial choice, not assume it is a cost-free enhancement.

Settlement currency and the FX spread

The settlement currency is the currency in which the acquirer pays the merchant. If a UK merchant sells mainly in US dollars but settles in sterling, the acquirer will convert each settlement. The rate may be based on an interbank reference plus a spread. A spread of 1% sounds modest, but it applies to gross cross-border volume, not profit. On £1 million of annual overseas sales, a 1% spread is £10,000 before any fixed fees.

Merchants should ask which reference rate is used, when it is sampled and whether the spread is fixed or tiered. Some contracts quote a margin over the acquirer's own card-scheme rate rather than a public interbank rate. That is not necessarily unacceptable, but it should be comparable. A useful discipline is to request a monthly FX statement showing the reference rate, the applied rate and the implied margin for each settlement currency.

A worked example

Assume a UK merchant sells €120,000 in a month to euro-area customers and settles into sterling. The acquirer applies an FX spread of 1.4% to its reference rate. If the reference rate implies £0.8600 per euro, the applied rate might be approximately £0.8480. The difference is about £1,440 for the month. Over a year, at the same volume, the embedded FX cost is roughly £17,280.

Now assume the merchant instead settles in euros and converts to sterling through its own treasury arrangement at a 0.5% spread. The saving depends on the merchant's banking access and operational capacity, but the example shows why settlement currency deserves a place in the negotiation. It also shows why a 0.2% reduction in the processing rate can be outweighed by a 0.9% improvement in the FX spread.

Chargebacks in a moving market

Chargebacks and refunds add a second currency exposure. A customer may dispute a €1,200 transaction weeks after the sale. If the merchant settled at one exchange rate and the chargeback is debited at another, the difference can be material when volumes are high. The contract should state the currency in which chargebacks are raised, the rate applied and whether the merchant can be debited in a different currency from the original settlement.

Merchants should reconcile chargeback debits against original transactions, not just against the monthly total. A rising gap between the two may indicate an embedded conversion cost or a timing mismatch. For high-ticket cross-border sales, it is worth asking whether chargebacks can be handled in the original transaction currency.

Contract clauses to mark up

Several clauses deserve close attention. Look for the settlement currency, the FX reference rate, the spread and the frequency of rate changes. Check the DCC participation terms, including who sets the rate, how consent is obtained and how revenue is shared. Review the chargeback and refund currency provisions. Confirm the currency of any reserve and whether the reserve is held in the same currency as settlement.

Also check set-off rights, fee-change clauses and volume commitments. A contract that permits the acquirer to change FX margins on short notice can erase the value of a negotiated processing rate. A contract that holds reserves in one currency while settling in another can create a mismatch if exchange rates move.

Negotiation tactics that work

Start with data. Present twelve months of cross-border volume by currency, average ticket, chargeback rate and settlement pattern. Ask for pricing in basis points by currency rather than a single blended rate. Request a fixed FX spread over a named reference rate for a defined period. If the merchant can operationally handle settlement in euros or dollars, ask for that option and compare it with the sterling settlement price.

Do not accept DCC as a default without understanding the economics. Ask for DCC to be optional by corridor and review the revenue share. Finally, test the acquirer's statement against your own reconciliation. The objective is not to eliminate every conversion cost, but to make sure each one is visible, comparable and proportionate to the value of the overseas sale.

Conclusion

Headline processing rates matter, but they are only one part of the cost of offshore settlement. UK merchants that examine DCC, settlement currency and FX spreads alongside chargeback exposure are better placed to protect margins in 2026. The exercise is part treasury review and part contract discipline, and it usually pays for itself in the first full reconciliation cycle.