Multi-currency accounting for cross-border SMEs.

Multi-currency accounting for SMEs means recording each transaction at the rate on the day it happens, restating outstanding foreign balances at the closing rate on the reporting date, and reporting the difference as an unrealised gain or loss. Realised gains arise separately when the money actually settles.

What does multi-currency accounting for SMEs involve?

Every transaction in your books has three currency-related properties: the transaction currency (what the customer paid in or supplier invoiced in), the functional currency (your reporting currency, set at company level), and any currency at point of bank settlement. For pure single-currency businesses these are all the same and you ignore the question. For cross-border businesses they diverge constantly.

The accounting consequence: every cross-currency transaction creates an FX position that closes when the bank settles. The difference between booked value and settled value is FX gain or loss, which lives somewhere on your P&L, often misclassified.

Setting up Xero multi-currency

Xero multi-currency is enabled in Settings → Currencies. Once on, you can:

• Issue invoices in any currency. Xero translates to your base currency at the daily exchange rate.
• Receive customer payments in any currency. Bank account currency determines how the payment lands.
• Pay suppliers in any currency. Same logic.
• Hold bank accounts in any supported currency, common for UK businesses to hold GBP, USD and EUR accounts simultaneously.

What Xero handles well

• Translation at transaction date.
• Revaluation at month-end for foreign-currency bank accounts.
• Realised gain/loss when a foreign-currency receipt or payment settles.
• Multi-currency bank reconciliation.

What Xero handles imperfectly

• Customers paying in a different currency than the invoice. Common for US customers paying a USD invoice from a GBP bank account, or vice versa. Requires manual journal to reconcile.
• Stripe / PayPal multi-currency settlements where the gateway converts. The conversion rate the gateway uses isn't always the daily Xero rate.
• Year-end balance-sheet revaluation under IAS 21 or FRS 102 (more on this below).

Wise as the treasury layer

Wise Business has become the de facto treasury layer for SMEs holding multiple currencies. A single Wise account gives you local bank details in GBP, USD, EUR, AUD, CAD, AED and others, meaning customers in those countries can pay you locally without the friction (or fee) of SWIFT transfers. Funds sit in Wise, in the currency received, until you convert or move them.

Why it matters for accounting

Wise should be treated as a bank account in your books, not as a payment gateway. Connect it via bank feed (Wise integrates with Xero, QuickBooks and most platforms) so transactions flow in real time. Reconcile monthly like any other bank account.

When you convert balances between currencies inside Wise, treat the conversion as a transfer between bank accounts. The FX gain or loss at conversion is the difference between the booked rate (when funds came in) and the conversion rate Wise actually used.

When to convert, when to hold

Treasury question, not accounting question, but worth addressing because most SMEs default to "convert everything to GBP immediately" and this costs money. If you have predictable foreign-currency outflows (USD supplier payments, EUR contractor costs), hold matching currency balances. If you don't, convert at the rate you're happy with rather than at receipt.

What is the unrealised FX trap at the year end?

Under UK GAAP (FRS 102) and IFRS, foreign-currency monetary items on the balance sheet at year-end must be retranslated at the closing rate. The difference between the opening rate (or transaction rate) and closing rate is an unrealised FX gain or loss that goes through P&L.

For SMEs with material foreign-currency exposure (a UK company holding $500,000 in a USD bank account, for example), this can be a meaningful number. If GBP strengthens against USD between transaction date and year-end, you book an unrealised FX loss equal to the value reduction in GBP terms. The cash hasn't moved; the value in your reporting currency has.

Where it goes wrong

• Many SMEs forget to do the year-end retranslation, leaving the balance sheet showing balances at historic rates. The error compounds year-on-year.
• Some retranslate but post the gain/loss to the wrong P&L line, operating profit rather than below-the-line "finance income" or "FX gains/losses". This distorts operating margin.
• Some retranslate but don't reverse the unrealised gain/loss in the following period, double-counting when the actual transaction settles.

Multi-currency tax considerations

Tax treatment of FX gains and losses is jurisdiction-specific and full of edge cases.

• UK: FX gains and losses on trading transactions are generally taxable as trading income. FX gains and losses on capital items (long-term holdings) can be capital. The matching rules under FA 1994 still apply for some items.
• US: Section 988 transactions generally produce ordinary income/loss. Section 1256 (regulated futures) is different. Foreign currency held as a personal asset can be capital.
• UAE: Under the 2023 Corporate Tax regime, FX gains and losses are generally part of taxable income, but the treatment of unrealised vs realised follows the accounting treatment.

Most SMEs don't need to optimise tax treatment of FX. The amounts are usually small relative to total trading. But for SMEs with material FX exposure (UK businesses with 30%+ USD revenue, for example), it's worth a conversation with your accountant.

The single most common multi-currency error we see at takeover: foreign-currency bank balances on the balance sheet at the date the bank account was opened: never retranslated, never reviewed, sometimes wrong by tens of thousands.

Practical setup for a typical cross-border SME

For a UK SME with US and EU customers, here's the setup we typically recommend:

• Base currency: GBP (your reporting currency).
• Bank accounts: GBP business account + Wise Business account with GBP/USD/EUR sub-balances.
• Xero configuration: Multi-currency enabled. USD and EUR added as supported currencies.
• Invoicing: Customer-currency invoicing: UK customers in GBP, US in USD, EU in EUR.
• Receipts: Customer-currency to matching Wise sub-balance. Hold or convert based on outflow needs.
• Suppliers: Pay in supplier currency where possible (from matching Wise sub-balance).
• Reconciliation: Monthly, all bank accounts. Year-end retranslation of all foreign-currency monetary items.

This setup costs ~£15/month in Wise fees (waived on small-volume accounts) and a few hundred pounds extra in annual accounting work. The alternative (accepting payments only in GBP, converting customer FX at their bank's rate) typically costs 1–3% of foreign revenue in FX margin paid to the customer's bank. For a business doing £500k of foreign-currency revenue, that's £5,000–£15,000 of margin lost annually.

The bottom line

Multi-currency accounting is a discipline, not a bolt-on. Set up Xero correctly with multi-currency enabled. Use Wise as the treasury layer. Reconcile monthly across all bank balances. Retranslate at year-end. Classify FX gains and losses correctly between operating and below-the-line. Done well, cross-border accounting is a non-event. Done badly, it's a recurring source of audit issues and tax surprises.

How does the year-end revaluation actually work?

Every foreign currency balance still outstanding at the year end is restated at the closing rate, and the difference goes to the profit and loss as an unrealised gain or loss. It is not optional and it is not a memo entry. The requirement sits in IAS 21 and, for UK entities, in the equivalent section of FRS 102 published by the Financial Reporting Council.

Worked example, illustrative rather than a real client. A UK agency invoices a US client $120,000 on 15 October when the rate is 1.25, recording £96,000 of revenue and a £96,000 debtor. At the 31 December year end the invoice is unpaid and the closing rate is 1.20.

The point of the table is the last row. Nothing about the underlying transaction changed, but £4,000 of profit was reported in a year it was never earned and reversed in the year after. For a business at the edge of a Corporation Tax band, or one whose covenant is measured on reported profit, that timing matters more than the amount.

Which rate should you actually use?

Three rates matter and they are not interchangeable. The transaction rate, applied when the invoice or bill is raised. The settlement rate, applied when the money moves, which is the rate that determines the real economic outcome. And the closing rate, applied to whatever remains outstanding at the reporting date.

The recurring error is using the accounting software's daily feed for all three and never checking the settlement rate against what the bank or payment provider actually charged. A payment provider quoting a rate with a spread built in produces a real cost that never appears as a fee line, and over a year of cross-border invoicing that gap is usually larger than the accountancy fee.

For tax, HMRC accepts the use of a consistent published rate, and the rate you use for the accounts is not automatically the rate that applies for a customs or VAT purpose. Businesses importing goods should read this next to HMRC guidance on VAT for purchases from abroad.

Who this matters to, and how we set it up

Cross-border SMEs where foreign currency is more than an occasional invoice: agencies with overseas clients, subscription businesses billing in more than one currency, and e-commerce brands selling into multiple regions. We configure and run it through our Xero multi-currency setup service, with the ongoing work in cloud bookkeeping services and the reporting through monthly management accounts.

Sellers dealing with multiple currencies and multiple marketplaces should pair this with cross-border e-commerce accounting and the Shopify and Amazon FBA chart of accounts. Groups with entities in more than one country will also need the market pages: accountants for UK SMEs, accountants for US small businesses and accountants for UAE SMEs, with structure questions handled through company incorporation across five countries. The forecasting side, which is where currency timing bites hardest, is covered in our 13 week cash flow template.