Key Points
- Translation applies the closing rate to assets and liabilities and historical or average rates to income and expenses.
- Exchange differences from translation accumulate in a separate component of equity called the foreign currency translation reserve.
- Groups with four or more foreign operations commonly carry translation reserves exceeding 5% of total equity.
- Recycling the reserve to profit or loss occurs only on disposal of the foreign operation, not when exchange rates reverse.
What foreign currency translation actually involves
On a recent group audit, the consolidation team applied the closing rate to every line of a Polish subsidiary's income statement. The translated profit was off by €1.2M, and nobody caught it until the engagement quality reviewer asked why the translation reserve had swung so hard. That kind of mistake happens more often than it should.
Foreign currency translation under IAS 21 is the process of converting the financial statements of a foreign operation from its functional currency into the group's presentation currency. IAS 21.39 requires translation of all assets and liabilities at the closing rate on each reporting date. Income and expenses use the exchange rates at the dates of the transactions, though IAS 21.40 permits an average rate when rates don't fluctuate significantly. Equity items stay at the historical rate from the date of acquisition or contribution.
Because these rates differ, an arithmetic mismatch produces an exchange difference that IAS 21.39 (c) directs to other comprehensive income. That difference accumulates in a separate equity reserve (often labelled "translation reserve") and stays there until the parent disposes of the foreign operation. On disposal, IAS 21.48 requires reclassification of the cumulative translation difference to profit or loss. ISA 600.40 (b) expects the group engagement team to evaluate whether the translation process and the resulting consolidation adjustments are complete. In practice, auditors test the rates applied, the method's consistency across periods, the OCI entry's mathematical accuracy, and whether the roll-forward reconciles to the prior year.
Worked example: Groupe Lefèvre S.A.
Client: Belgian holding company, FY2025, consolidated revenue €185M, IFRS reporter. Groupe Lefèvre's presentation currency is EUR. It owns 100% of Lefèvre Polska sp. z o.o., a Polish distribution subsidiary whose FC is PLN. The subsidiary reports revenue of PLN 120M and net assets of PLN 80M.
Step 1. Translate the balance sheet at the closing rate
At 31 December 2025 the EUR/PLN closing rate is 4.35. Total assets of PLN 200M translate to €46.0M. Total liabilities of PLN 120M translate to €27.6M. Net assets translate to €18.4M.
Step 2. Translate the income statement at average rates
The weighted-average EUR/PLN rate for FY2025 is 4.28. Revenue of PLN 120M translates to €28.0M. Operating expenses of PLN 108M translate to €25.2M. Profit after tax of PLN 12M translates to €2.8M.
Step 3. Translate equity at historical rates
Share capital of PLN 40M was contributed at formation when the EUR/PLN rate was 4.10, translating to €9.8M. Retained earnings at the start of FY2025 were PLN 28M, carried forward at the cumulative historical translated amount of €6.8M.
Step 4. Calculate the translation difference
Translated net assets at the closing rate are €18.4M (from Step 1). The sum of translated equity components is: share capital €9.8M plus opening retained earnings €6.8M plus current-year profit €2.8M, totalling €19.4M. The translation difference for FY2025 is €18.4M minus €19.4M, producing a loss of €1.0M recognised in OCI.
PLN weakening against the EUR during FY2025 produces a €1.0M translation loss in OCI. The approach is defensible because each rate applied matches the IAS 21 requirement for its category: closing for the balance sheet, average for the income statement, historical for equity contributions, and the residual flows to OCI as required by IAS 21.39 (c).
Why it matters in practice
Teams frequently apply the closing rate to the income statement instead of the average rate, or apply a single average rate to both the balance sheet and the income statement. IAS 21.39 requires different rates for different elements. Using the closing rate for revenue and expenses overstates or understates translated profit depending on the direction of currency movement, and the resulting translation reserve is correspondingly wrong. ISA 600.40 (b) expects the group engagement team to verify that the translation method is consistent with IAS 21 . On too many files we've reviewed, the translation working paper is a tick box exercise: someone pastes in the closing rate, plugs a formula, and moves on without checking that the income statement used the average rate.
Practitioners often fail to maintain a cumulative equity roll-forward in the translated currency. Without this schedule, the translation difference becomes a balancing figure that nobody can independently recalculate. IAS 21.39 (c) defines the translation difference as the residual, but the residual must be verifiable. This is the finding that generates the most review notes on group audits. When the roll-forward is absent, year-on-year movements in the reserve cannot be explained to the engagement quality reviewer, and the file should tell a story that connects the opening reserve to the closing balance through clearly documented rate movements.
Foreign currency translation vs. foreign currency transaction
| Dimension | Foreign currency translation ( IAS 21.38 –49) | Foreign currency transaction ( IAS 21.21 –37) |
|---|---|---|
| What is converted | An entire set of FS of a foreign operation | A single transaction denominated in a currency other than the entity's FC |
| Where differences go | Other comprehensive income (translation reserve) | Profit or loss |
| Rate applied to monetary items | Closing rate on the balance sheet date | Closing rate on the balance sheet date (same rate, but the gain or loss hits a different statement) |
| Reclassification to P&L | Only on disposal of the foreign operation | Immediately, each reporting period |
| Typical audit focus | Consistency of rate application across the balance sheet, income statement, equity, and the translation reserve roll-forward; completeness of the OCI entry | Accuracy of the spot rate at the transaction date and the remeasurement at the reporting date |
The distinction matters because mixing the two treatments misstates both profit and OCI. A foreign-currency receivable held by the parent in its own books is a transaction ( IAS 21.28 remeasurement through profit or loss). The same receivable appearing in a foreign subsidiary's local-currency statements is translated as part of the subsidiary's balance sheet ( IAS 21.39 through OCI on consolidation).
Related terms
Related reading
Frequently asked questions
How do I choose between the closing rate and an average rate for income and expenses?
IAS 21.40 permits an average rate as a practical approximation when exchange rates do not fluctuate significantly during the period. If rates are volatile (the standard does not define a threshold, but movements exceeding 10% within a quarter are a common trigger), the entity should translate individual transactions at the rate on the transaction date. The auditor tests whether the approximation method is reasonable by comparing the average-rate result to a sample of transaction-date translations.
Does foreign currency translation apply to branches as well as subsidiaries?
Yes. IAS 21.38 applies the translation method to any foreign operation, which IAS 21.8 defines as a subsidiary, associate, joint arrangement, or branch whose activities are based in a country or currency different from the reporting entity. A branch with a different functional currency follows the same closing-rate and average-rate method as a subsidiary. The translation difference flows to OCI in the same way.
What happens to the translation reserve when I sell part of a foreign operation?
IAS 21.48A requires proportionate reclassification. If the parent sells 30% of a subsidiary while retaining control, 30% of the cumulative translation reserve attributable to that subsidiary is reclassified from OCI to profit or loss. The remaining 70% stays in equity. The proportion follows the ownership interest disposed of, and the non-controlling interest is adjusted accordingly under IFRS 10.B96.