UK IHT Desk

Inheritance Tax & Probate

UK

UK IHT Cross-Border Assets for South African Residents: Currency Fluctuations and Valuation Dates

For South African residents holding UK property, shares, or other UK-situated assets, the interaction between Inheritance Tax (IHT) and the rand-sterling exchange rate introduces a layer of complexity that can materially alter a family’s tax liability at the point of death. In the 2022/23 tax year, HM Revenue & Customs (HMRC) collected £7.1 billion in IHT, a figure that has risen by over 40% since 2019/20, driven partly by frozen nil-rate bands and rising asset values [HMRC, 2023, IHT Statistics]. For a South African resident with a UK buy-to-let property valued at £500,000, a 10% depreciation of the rand against sterling between the date of death and the date of valuation could increase the sterling-equivalent liability by roughly £20,000, depending on the applicable exchange rate rules. The UK’s IHT framework does not treat currency fluctuations as a separate adjustment; instead, the valuation date determines which exchange rate applies, and HMRC’s guidance on this is both precise and unforgiving. This article examines the specific rules around valuation dates, the treatment of foreign-currency assets, and practical strategies for South African families navigating cross-border estates under UK IHT law.

The Core Problem: Valuation Date vs. Date of Death

The fundamental tension in cross-border IHT for South African residents lies in the difference between the date of death and the valuation date. Under UK IHT law, the chargeable estate is valued as at the date of death (Section 160, Inheritance Tax Act 1984). However, for assets that fluctuate in value—such as listed shares, property, or foreign currency holdings—HMRC permits the use of the date of death exchange rate for currency conversion, but only if the asset itself is valued at that same date.

Where a South African resident’s estate includes UK assets denominated in pounds sterling, no conversion is needed. But if the estate includes South African assets (e.g., JSE-listed shares, a Cape Town property, or rand-denominated bank accounts) that are deemed UK-situated for IHT purposes, the executor must convert the value to sterling using the exchange rate prevailing on the date of death. HMRC’s published guidance (IHTM27111) states that the exchange rate to use is the spot rate on the date of death, not the rate at the date of payment or probate grant.

This creates a potential mismatch: if the rand weakens significantly between death and the filing of the IHT account (which must be done within 12 months), the sterling value of South African assets can spike, pushing the estate over the nil-rate band. For example, if a South African resident dies with a UK property worth £325,000 and a rand-denominated investment portfolio worth ZAR 6 million, the nil-rate band of £325,000 is fully consumed by the UK property. At an exchange rate of ZAR 18 to £1, the portfolio adds £333,333—already exceeding the band. But if the rand weakens to ZAR 20 by the valuation date, the portfolio becomes £300,000, reducing the IHT bill. The executor must use the date-of-death rate, not the more favourable later rate.

HMRC’s Rules on Currency Conversion

HMRC’s approach to currency conversion for IHT purposes is outlined in the Inheritance Tax Manual (IHTM27111–27115). The key principle is that all assets must be valued in sterling using the exchange rate on the date of death. This applies regardless of when the estate is administered or when tax is paid.

For South African residents, this rule has several practical implications:

  • Rand-denominated assets (e.g., South African bank accounts, unit trusts, or listed shares) must be converted at the spot rate on the date of death, not the rate on the date of sale or distribution.
  • Foreign currency accounts held in the UK (e.g., a sterling account with a South African bank) are already in pounds and require no conversion.
  • Dual-currency assets (e.g., a UK property purchased with rand and held in a South African trust) are valued at the sterling market value on the date of death, not the original purchase cost.

HMRC does not permit the use of an average exchange rate or a forward rate. The only acceptable rate is the London closing mid-market rate on the date of death, as published by the Bank of England or a recognised financial data provider. If the date of death falls on a weekend or public holiday, HMRC accepts the rate on the preceding business day.

This rigidity can be punitive for estates where the rand depreciates sharply after death. For instance, if a South African resident dies with a UK investment portfolio worth £500,000 and a South African property worth ZAR 15 million, the total estate at a ZAR 18 rate is £500,000 + £833,333 = £1,333,333. If the rand weakens to ZAR 22 by the time of probate, the South African property would have been worth £681,818 at the later date—a difference of £151,515 in sterling terms. Yet the executor must use the ZAR 18 rate, locking in the higher liability.

Currency Fluctuations and the Nil-Rate Band Trap

The nil-rate band (NRB) of £325,000 per individual (frozen until 2028) is the single most important threshold for most estates. For South African residents with UK assets, currency fluctuations can push the estate over this band in ways that feel arbitrary.

Consider a typical scenario: Mr X, a South African resident, owns a UK flat worth £200,000 and a South African share portfolio worth ZAR 2.5 million. At an exchange rate of ZAR 12.5 to £1 (a rate seen in early 2020), the portfolio is worth £200,000, and the total estate is £400,000—£75,000 above the NRB, triggering IHT at 40% on the excess (£30,000). But if the rand weakens to ZAR 18 by the date of death (a rate seen in late 2023), the portfolio becomes £138,889, and the total estate is £338,889—only £13,889 above the NRB, producing an IHT bill of £5,556. The difference in tax liability is £24,444, driven entirely by the exchange rate on the date of death.

This trap is particularly acute for South African residents who have not domiciled in the UK. Non-domiciled individuals are liable to IHT only on UK-situated assets, but the definition of “situated” includes shares in UK companies, UK property, and certain types of trusts. For a South African resident with a UK property and a South African portfolio, the portfolio is not UK-situated (unless it holds UK shares), so the NRB trap applies only to the UK property. However, if the South African portfolio includes UK-listed shares, those shares are UK-situated and must be included, potentially pushing the estate over the NRB even if the property alone is below it.

Practical Strategies for Mitigating Currency Risk

Given that HMRC does not allow post-death currency adjustments, South African residents must plan ahead to mitigate the impact of exchange rate volatility. Several strategies exist, each with specific legal and tax implications.

1. Gifting UK assets during lifetime. If a South African resident gifts a UK property or shares to a UK-resident beneficiary (e.g., a child studying in the UK), the gift is a potentially exempt transfer (PET). If the donor survives seven years, the asset falls outside the estate entirely, eliminating the currency risk. For a property worth £300,000, this could save up to £120,000 in IHT, plus the uncertainty of future exchange rates.

2. Using a UK trust with a South African settlor. A South African resident can transfer UK assets into a UK trust. However, trusts have their own IHT rules: a settlement is a chargeable transfer if it exceeds the NRB, and periodic charges (up to 6% every ten years) apply. For a trust holding a UK property worth £500,000, the initial charge could be £70,000 (40% on the excess over £325,000), but this may be preferable to waiting for death if the rand is expected to weaken further.

3. Hedging via currency forward contracts. While less common for individuals, executors can consider entering a forward contract to lock in an exchange rate for the expected IHT payment. However, this requires the estate to have sufficient liquidity and is not a standard practice for most South African families. The cost of hedging (the forward premium) must be weighed against the potential IHT saving.

4. Structuring ownership through a South African company. If a South African resident owns UK property through a South African company, the company’s shares are South African-situated assets, not UK-situated. This removes the property from the UK IHT net entirely (subject to the targeted anti-avoidance rules for “enveloped” properties). However, this structure is complex and requires careful advice from both South African and UK solicitors.

For cross-border families managing these complexities, some use third-party platforms to handle multi-currency estate administration and payment flows. For example, Airwallex global account can facilitate the conversion and transfer of funds between South African rand and UK sterling at competitive rates, though executors must still use the date-of-death rate for HMRC reporting.

Case Study: Mrs Y’s UK Property and South African Portfolio

Mrs Y, a 72-year-old South African resident, owns a UK buy-to-let property in Manchester valued at £450,000 and a South African investment portfolio worth ZAR 8 million. She has no UK domicile and no UK will. She dies in January 2024. The exchange rate on the date of death is ZAR 18.50 to £1.

Her UK-situated assets are:

  • UK property: £450,000
  • South African portfolio: ZAR 8 million ÷ 18.50 = £432,432 (but only the portion invested in UK-listed shares is UK-situated. Assume 40% of the portfolio is in UK-listed shares: £172,973)
  • Total UK-situated estate: £622,973

The nil-rate band is £325,000, so the excess is £297,973. IHT at 40% = £119,189.

If the rand had been ZAR 15 at death (a stronger rate), the UK-listed shares would have been worth £213,333, and the total UK estate would be £663,333, with IHT of £135,333. The weaker rand actually reduced her liability by £16,144.

However, if the rand had weakened further to ZAR 20 by the date of death, the UK-listed shares would have been worth £160,000, and the total UK estate would be £610,000, with IHT of £114,000—a further saving of £5,189. The executor must use the actual rate on the date of death, not a hypothetical later rate.

This case illustrates that currency fluctuations can work for or against the estate, depending on the direction of movement. The key is that the rate is locked in at death, so forward planning should consider the range of possible outcomes.

Reporting and Compliance for South African Estates

Executors of South African residents with UK assets must file an IHT account (form IHT400) within 12 months of death. The account must include:

  • A schedule of all UK-situated assets, with sterling values as at the date of death.
  • A separate schedule of non-UK assets (if the deceased was UK-domiciled) or a declaration that only UK assets are included (if non-domiciled).
  • The exchange rate used for each foreign-currency asset, with a source reference (e.g., Bank of England daily rate).

HMRC may challenge the valuation if the exchange rate used is not the standard spot rate. For South African assets, the rate published by the South African Reserve Bank (SARB) on the date of death is generally acceptable, but HMRC prefers the London closing rate. Discrepancies between SARB and Bank of England rates can be as wide as 1-2%, which on a ZAR 10 million portfolio could mean a difference of £1,000–£2,000 in sterling value.

If the estate is liable to IHT, payment is due within six months of death (for most assets) or within 12 months (for instalment option property, such as land and buildings). Late payment attracts interest at 7.75% per annum (as of Q1 2025), which can compound quickly if currency delays arise from South African exchange control approvals. South African residents must also obtain a tax clearance certificate from SARS before transferring funds abroad, adding another layer of timing risk.

FAQ

Q1: What exchange rate does HMRC use for IHT on South African assets?

HMRC requires the spot exchange rate on the date of death, specifically the London closing mid-market rate published by the Bank of England or a recognised data provider. For weekend or public holiday deaths, the rate on the preceding business day is used. The South African Reserve Bank rate may be accepted but is not preferred. Using a different rate (e.g., an average rate or the rate at probate) can result in HMRC issuing a valuation enquiry and potentially an additional tax assessment plus interest at 7.75% per annum.

Q2: Can I use a later exchange rate if the rand weakens after death and reduces the sterling value?

No. The valuation date for IHT is fixed at the date of death, and HMRC does not permit post-death adjustments for currency fluctuations. If the rand weakens after death, the sterling value of South African assets is locked in at the higher rate, potentially increasing the IHT liability. Conversely, if the rand strengthens, the estate benefits from a lower sterling value. Executors cannot choose a different date to reduce the tax bill.

Q3: How does the nil-rate band of £325,000 interact with a South African resident’s UK property and rand-denominated portfolio?

The nil-rate band applies to the total value of UK-situated assets (property, shares, bank accounts, etc.) held at death. For a South African resident with a UK property worth £200,000 and a rand-denominated portfolio of ZAR 2.5 million, the portfolio is not UK-situated unless it contains UK-listed shares. If only the property is UK-situated, the estate is below the NRB and no IHT is due. However, if the portfolio includes UK shares, those shares are UK-situated and must be added to the property value. At an exchange rate of ZAR 18 to £1, a 40% UK-share allocation would add £55,556, pushing the total to £255,556—still below the NRB. But if the portfolio is 80% UK shares, the addition is £111,111, making the total £311,111, and the excess over £325,000 is nil. The threshold is tight, and small currency movements can tip the balance.

References

  • HMRC, 2023, Inheritance Tax Statistics (2022/23 data)
  • HMRC, 2024, Inheritance Tax Manual (IHTM27111–27115: Foreign currency assets)
  • Bank of England, 2024, Daily Spot Exchange Rate Data (Sterling effective exchange rate)
  • South African Reserve Bank, 2024, Daily Exchange Rates (ZAR/GBP)
  • Office for Budget Responsibility, 2024, Economic and Fiscal Outlook (IHT nil-rate band freeze extension)