Foreign Exchange Differences Under IAS 21: Rules and Examples

Foreign Exchange Differences Under IAS 21

Foreign exchange differences arise because a transaction denominated in a foreign currency is measured on one date but settled on another, and the exchange rate moves in between.

The standard resolves this with three rules:

1. record the transaction at the spot rate on the transaction date,
2. retranslate monetary items at the closing rate every reporting date, and
3. leave non-monetary items at their historical rate unless they are remeasured.

Everything else — realised versus unrealised differences, hedged positions, foreign operations — follows from those three rules.

Throughout this article the reporting entity is a UK company whose functional currency is sterling (GBP), transacting in US dollars (USD). All exchange rates are quoted as £ per $1, so a rate of 0.75 means $1 buys £0.75, and a strengthening dollar pushes the rate up.

Foreign, Functional and Reporting Currency

IAS 21 works with three distinct currency concepts

For our UK company, sterling is both the functional and the presentation currency, and the dollar is a foreign currency. That is the ordinary case, and it is the case this article covers: foreign currency transactions recorded in a single functional currency.

How Exchange Differences Arise

An exchange difference is simply the difference that arises on translating the same number of foreign currency units at two different exchange rates. It has nothing to do with the underlying business performing better or worse.

Consider a $100,000 payable owed by our sterling entity:

The dollar obligation never changed. The sterling obligation moved from £75,000 to £80,000, so the entity recognises a £5,000 exchange loss — £3,000 in X1 and £2,000 in X2. That £5,000 is the exchange difference, and it exists solely because the transaction date and the settlement date are not the same day.

Three dates therefore matter for every foreign currency balance:

• Transaction date — when the item is first recognised, at the spot rate.
• Reporting date — when monetary balances still outstanding are retranslated at the closing rate.
• Settlement date — when cash moves, at the spot rate on that day.

Initial Recognition at the Spot Rate

A foreign currency transaction is recorded on initial recognition by applying the spot exchange rate at the date of the transaction to the foreign currency amount. The transaction date is the date on which the transaction first qualifies for recognition under the relevant standard — delivery date for an inventory purchase, drawdown date for a loan, commencement date for a lease.

IAS 21 permits a rate that approximates the actual rate. In practice this means a weekly or monthly average rate is acceptable, provided exchange rates have not fluctuated significantly. A period of volatility removes that concession, and actual daily rates must be used.

Monetary vs Non-Monetary Items

Everything after initial recognition depends on this classification.

The essential feature of a monetary item is a right to receive (or an obligation to deliver) a fixed or determinable number of units of currency.

Ask one question: **does this balance entitle me to, or oblige me to hand over, a set amount of cash?

If the balance will be settled by delivering goods or services, or represents an ownership interest rather than a claim to cash, it is non-monetary.

The Three Reporting Date Rules

At each reporting date, IAS 21 applies one of three rules depending on the item's classification and measurement basis.

When a non-monetary item is remeasured — a fair value adjustment, a revaluation, an impairment, a write-down to net realisable value — the new measurement is translated at the rate on the date of that measurement. The exchange effect is therefore bundled into the remeasurement and is not split out.

It also follows the remeasurement's destination: if the revaluation goes to other comprehensive income, so does the exchange component; if it goes to profit or loss, so does the exchange component.

Realised vs Unrealised Exchange Differences

The two labels describe when an exchange difference crystallises, not how it is measured.

• An unrealised exchange difference arises from retranslating a monetary balance that is still outstanding at the reporting date. No cash has moved; it is a pure remeasurement.
• A realised exchange difference arises on settlement, when cash actually changes hands at the settlement date spot rate. The gain or loss is locked in.

Using the $100,000 payable above: the £3,000 loss recognised at 31 December X1 is unrealised, because the liability is still outstanding. The further £2,000 loss on payment at 1 March X2 is realised, and the £3,000 previously unrealised becomes realised at that point too. IAS 21 treats both identically — profit or loss in the period in which they arise — and does not require them to be presented separately.

The distinction is however importnat in two places outside the income statement:

The cash flow statement. Unrealised differences are not cash flows at all and must be eliminated from profit. Realised differences are cash flows, but they need to be reclassified so they follow the underlying transaction rather than defaulting to operating activities. The mechanics of both adjustments, including the separate "effect of exchange rate changes on cash" line, are covered in detail in our article on foreign exchange transactions in the cash flow statement.

Tax. Many jurisdictions tax exchange differences on an accruals basis that broadly follows IAS 21, but defer recognition in specific cases. South Africa has 3 key types:

• foreign debt used to acquire an asset not yet brought into use,
• long-term loans between connected parties, and
• forward contracts entered into before the underlying transaction.

Where the tax treatment defers what accounting recognises, a temporary difference originates and deferred tax must be provided.

Where Exchange Differences Are Recognised

Example 1: Importing Inventory on Credit

The classic monetary liability.

• 30 June X1 — the entity purchases inventory for $100,000
• Settlement — payable in dollars on 1 March X2
• Year end — 31 December
• Inventory — held at a foreign branch and unsold at 31 December X1
• Rates (£ per $1) — 30 June X1: 0.75; 31 December X1: 0.78; 1 March X2: 0.80

The two sides of the original entry now behave completely differently:

• The payable is monetary. It is retranslated at every closing rate and on settlement, producing a total exchange loss of £5,000 in profit or loss.
• The inventory is non-monetary and carried at cost. It stays at £75,000 for as long as it is held, and is charged to cost of sales at £75,000 when sold. The exchange rate is irrelevant to it.

Total cash outflow is £80,000 on 1 March X2 — that is the figure the cash flow statement must show, which is precisely why the realised £5,000 has to be folded into cash paid to suppliers rather than left as a separate exchange line in the reconciliation from profit.

Example 2: Export Sale Settled in Instalments

The mirror image, with a part-settlement.

• 30 June X4 — the entity sells inventory for $100,000
• 30 September X4 — receives $50,000
• 31 March X5 — receives the balance of $50,000
• Year end — 31 December
• Rates (£ per $1) — 30 June X4: 0.70; 30 September X4: 0.74; 31 December X4: 0.76; 31 March X5: 0.80

The cleanest way to handle staged settlement is to run a receivable ledger in both currencies, calculating each exchange difference on the dollars affected and the rate movement over the period they were held.

Revenue is fixed at £70,000 — it was recognised at the transaction date rate and is never revisited. Total cash collected is £77,000, and the £7,000 excess is an exchange gain: £5,000 in X4 (of which £2,000 realised and £3,000 unrealised) and £2,000 in X5.

Example 3: Inventory Written Down to Net Realisable Value

Non-monetary, but remeasured.

• Facts — continuing Example 1: inventory purchased for $100,000
• 31 December X1 — net realisable value is $90,000
• Sales currency — dollars

Inventory is non-monetary and would ordinarily sit at its historical rate. But the lower of cost and net realisable value test is a remeasurement, so IAS 21's third rule applies — and the two sides of the comparison are translated at different rates.

The single journal is Dr Write-down of inventory (P/L) £4,800, Cr Inventory (SFP) £4,800.

Example 4: Foreign Equity Investment

Non-monetary at fair value.

• Holding — dollar-denominated shares
• Fair value — $50,000 at the start of the year, $55,000 at year end
• Rates (£ per $1) — opening 0.80, closing 0.76

The classification of the investment decides only where the £1,800 lands:

Note what is absent: there is no exchange difference line. The shares gained $5,000 in value while the dollar weakened, and the two effects net to a single £1,800 gain that is recognised as an ordinary fair value adjustment. The exchange component simply follows the fair value movement to whichever statement it belongs in. The same logic applies to a revalued foreign property — the revaluation surplus in other comprehensive income silently carries the currency effect with it.

Example 5: Deferred Payment with a Financing Component

Where interest and currency interact.

• 30 November X1 — the entity buys equipment for $500,000
• Settlement — payable in full on 30 November X3
• Financing — two years' credit is not the industry norm, so the arrangement contains a significant financing component
• Market-related rate — 12% per annum
• Year end — 30 November

The purchase price is first discounted in the foreign currency, then translated at the transaction date spot rate. Discounting $500,000 for two years at 12% gives $398,597.

Rates (£ per $1): spot 30 November X1 — 0.70; average X2 — 0.74; spot 30 November X2 — 0.78; average X3 — 0.82; spot 30 November X3 — 0.85.

Interest accrues over the period, so it is translated at the average rate for the period. The closing liability is monetary, so it is translated at the closing spot rate. The exchange difference is then the balancing figure.

The journals in the year to 30 November X2 are:

• Dr Finance costs (P/L) £35,396
• Dr Exchange difference (P/L) £33,801
• Cr Payable (SFP) £69,197

Settlement on 30 November X3 is:

• Dr Payable (SFP) £425,000
• Cr Bank (SFP) £425,000

Meanwhile the equipment is recognised once, at £279,018, and depreciated off that sterling figure for its whole life. It is non-monetary and carried at cost, so none of the £66,658 of exchange differences or £79,324 of interest ever touches it. A cash outflow of £425,000 eventually settles an asset recorded at £279,018 — the entire gap runs through profit or loss.

Example 6: Hedging with a Forward Exchange Contract

Two instruments, two standards.

• 1 April X4 — the entity takes out a seven-month forward exchange contract to buy $100,000 on 1 November X4 at a forward rate of 0.75
• 1 May X4 — purchases equipment for $100,000
• 1 November X4 — settles the supplier using the dollars acquired under the contract
• Year end — 30 June
• Hedge accounting — assume it is not applied, so the forward contract is measured at fair value through profit or loss under IFRS 9
• Spot rates (£ per $1) — 1 April: 0.72; 1 May: 0.74; 30 June: 0.78; 1 November: 0.80
• Comparable forward rate — at 30 June, for a contract maturing 1 November: 0.79

Keep the two instruments separate — the creditor follows IAS 21 at spot rates, the forward contract follows IFRS 9 at forward rates:

Reading the result:

• The exchange loss on the creditor is £6,000; the gain on the forward contract is £5,000. Net cost to profit or loss: £1,000. That residual is exactly $100,000 × (0.75 − 0.74) — the difference between the forward rate contracted on 1 April and the spot rate on the transaction date of 1 May. Everything else offsets, which is the hedge doing its job even without hedge accounting.
• Cash out is £75,000, the rate the entity locked in, not the £80,000 spot value of the payable.
• The equipment stays at £74,000. Neither the exchange differences nor the hedge result adjusts it.

Example 7: Advance Payment for Inventory

Non-monetary, and never retranslated.

• Purchase — $100,000 of inventory from a US supplier
• 1 October X1 — the entity pays a non-refundable deposit of $30,000
• 1 March X2 — the goods are delivered and the remaining $70,000 becomes payable
• 30 April X2 — the entity pays the $70,000 balance
• Year end — 31 December
• Rates (£ per $1) — 1 October X1: 0.72; 31 December X1: 0.78; 1 March X2: 0.80; 30 April X2: 0.84

The inventory ends up at £77,600, made of two slices translated at two different rates, and the only exchange difference in the whole transaction is the £2,800 on the monetary payable. Retranslating the deposit at 31 December would have put a spurious £1,800 loss through profit or loss and carried an inflated cost into inventory.

Quick Reference Summary

Conclusion

Foreign exchange accounting under IAS 21 is largely driven by what happens to the underlying balance after initial recognition. Foreign currency transactions are initially recorded at the spot rate on the transaction date. Monetary items are subsequently retranslated at the closing rate, while non-monetary items measured at historical cost remain at their original rate. Non-monetary items measured at fair value use the exchange rate at the date that fair value is measured, with the resulting exchange effect following the treatment of the underlying gain or loss.

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