US shares are one of the most common surprises in Irish estates. Many people held a few US technology stocks, an employer share scheme, or a US brokerage account — and the rules for transferring them after death are very different from Irish assets. For the wider picture, see our guide to cross-border inheritance in Ireland.
Two issues sit at the heart of this. First, US-incorporated shares are treated as located in the US for estate tax, which can create a US tax charge even where everyone involved is Irish. Second, the practical steps to release the shares — an IRS transfer certificate and a Medallion Signature Guarantee — are unfamiliar and can take time. This guide explains both, and how Irish CAT interacts with the US charge.
When are US shares treated as US-situs?
“Situs” means the location an asset is treated as having for tax. For shares, situs follows the place of incorporation, not where the shareholder lived or where the certificate is kept. Shares in a US-incorporated company are therefore US-situs, which is what brings them within US federal estate tax even for an Irish-resident shareholder.
This catches more estates than people expect. Holding US shares through an Irish stockbroker or a nominee account does not change the situs — the underlying company is still US-incorporated. By contrast, cash in a US bank account is specifically excluded from US estate tax for non-resident non-citizens, even though shares are not.
Shares in a US-incorporated company (e.g. Apple, Microsoft, held directly)
Yes — US-situs
Situated where the company is incorporated. Registered US shares are within the US estate tax charge regardless of where the certificate is held.
US shares held through an Irish or non-US broker or nominee
Usually yes — US-situs
The underlying shares remain US-incorporated, so they stay within the US charge. The nominee arrangement does not change the situs.
Shares in an Irish or UK company quoted on a US exchange (ADRs vary)
Often no
Situs follows the place of incorporation, not the exchange. Depositary receipts need case-by-case analysis — take advice.
US-domiciled mutual funds and most US-listed ETFs
Generally yes — US-situs
Treated as US-situs assets. Many Irish investors instead hold Irish-domiciled (UCITS) funds, which are not US-situs.
Cash in a US bank account of a non-US-resident
Generally not US-situs for estate tax
Deposits with US banks are specifically excluded from US estate tax for non-resident non-citizens, though shares and securities are not.
How common US-linked holdings are treated for US estate tax. Treatment can be technical — take advice on significant holdings.
| Asset | US-situs for estate tax? | Why |
|---|---|---|
| Shares in a US-incorporated company (e.g. Apple, Microsoft, held directly) | Yes — US-situs | Situated where the company is incorporated. Registered US shares are within the US estate tax charge regardless of where the certificate is held. |
| US shares held through an Irish or non-US broker or nominee | Usually yes — US-situs | The underlying shares remain US-incorporated, so they stay within the US charge. The nominee arrangement does not change the situs. |
| Shares in an Irish or UK company quoted on a US exchange (ADRs vary) | Often no | Situs follows the place of incorporation, not the exchange. Depositary receipts need case-by-case analysis — take advice. |
| US-domiciled mutual funds and most US-listed ETFs | Generally yes — US-situs | Treated as US-situs assets. Many Irish investors instead hold Irish-domiciled (UCITS) funds, which are not US-situs. |
| Cash in a US bank account of a non-US-resident | Generally not US-situs for estate tax | Deposits with US banks are specifically excluded from US estate tax for non-resident non-citizens, though shares and securities are not. |
The practical takeaway is to identify early which holdings are genuinely US-situs. That decides whether a US estate tax return and an IRS transfer certificate are needed, and it shapes the Irish CAT position too. Where the answer is unclear — for example with depositary receipts or mixed fund structures — it is worth confirming rather than assuming.
US estate tax exposure for a non-resident estate
US federal estate tax is charged on the estate of the person who died, on the value of their US-situs assets. For someone who was neither a US citizen nor US-domiciled, a low $60,000 filing threshold applies and it is not index-linked. Above that, US estate tax can apply at rates up to 40%.
The $60,000 is not a simple cap on US assets at death. The executor must file Form 706-NA where the total of the US-situs assets at death, plus any adjusted taxable gifts (US gifts made since 1977) and the gift tax specific exemption used, exceeds $60,000. So substantial US lifetime gifts can trigger a filing even where US assets at death look modest.
US estate tax vs Irish CAT: the key differences
US federal estate tax and Irish Capital Acquisitions Tax (CAT) work on opposite principles, which is why the same shares can be taxed in both countries. US estate tax is charged on the estate before distribution; CAT is charged on each beneficiary on what they receive. Understanding the two helps you see where the treaty credit fits.
Tax name
US Federal Estate Tax
Capital Acquisitions Tax (CAT)
Top rate
Up to 40%
33%
Who is charged
The estate of the person who died (on US-situs assets)
The beneficiary who receives the inheritance
Tax-free amount
$60,000 filing threshold for non-US-domiciled, non-citizen decedents (US-situs assets plus adjusted taxable gifts)
€400,000 (Group A), €40,000 (Group B), €20,000 (Group C)
What triggers the charge
US-situs assets (including US-incorporated shares) above the $60,000 threshold, counting adjusted taxable gifts
Irish-resident/domiciled disponer or beneficiary, or Irish-situs assets
Relief for the other country's tax
Limited under domestic law; the treaty allocates taxing rights
Credit for US estate tax under the Ireland–US treaty (Finance Act 1950)
Comparison of US federal estate tax and Irish CAT. Thresholds current as of June 2026.
| United States | Ireland | |
|---|---|---|
| Tax name | US Federal Estate Tax | Capital Acquisitions Tax (CAT) |
| Top rate | Up to 40% | 33% |
| Who is charged | The estate of the person who died (on US-situs assets) | The beneficiary who receives the inheritance |
| Tax-free amount | $60,000 filing threshold for non-US-domiciled, non-citizen decedents (US-situs assets plus adjusted taxable gifts) | €400,000 (Group A), €40,000 (Group B), €20,000 (Group C) |
| What triggers the charge | US-situs assets (including US-incorporated shares) above the $60,000 threshold, counting adjusted taxable gifts | Irish-resident/domiciled disponer or beneficiary, or Irish-situs assets |
| Relief for the other country's tax | Limited under domestic law; the treaty allocates taxing rights | Credit for US estate tax under the Ireland–US treaty (Finance Act 1950) |
CAT thresholds depend on the relationship between the person who died and the beneficiary, and they are lifetime, cumulative figures. For a fuller explanation of how the thresholds, the 33% rate, and the 80% filing trigger work, see our inheritance tax (CAT) guide. The treaty credit, explained below, then reduces the risk of paying both taxes in full.
How the Ireland–US estate tax treaty prevents double taxation
Ireland and the US have a bilateral estate tax treaty, given effect in Irish law by the Finance Act 1950. It coordinates US federal estate tax and Irish CAT so that the same property is not fully taxed twice. It does this through a credit: Ireland gives credit for US estate tax paid on the same US-situs property.
The credit is calculated at the lower of the US or the Irish effective tax rate, and it cannot exceed the Irish tax payable on that property. The treaty also contains a situs code that determines, for each class of asset, which country has the primary taxing right — for shares, that is the place of incorporation.
One important limit: the treaty covers federal estate tax and Irish CAT, but it does not cover US gift tax or US state-level death duties. Where a US state imposes its own charge, that may not be relieved under the treaty. This is another reason to involve a US estate tax advisor on significant holdings.
Releasing the shares: transfer certificate and Medallion Guarantee
A transfer agent is the company that maintains a US company's share register and processes ownership changes. For a deceased non-resident, the transfer agent or broker generally will not move the shares until it receives an IRS transfer certificate (Form 5173) confirming the US estate tax has been dealt with. This is often the longest step.
The IRS issues the transfer certificate once it is satisfied the US estate tax has been paid or that none is due. The IRS acknowledges the process can take a year or longer. Because it runs in parallel with the Irish grant, it is best to start the US application as early as possible rather than waiting until the Irish administration is finished.
Separately, to actually transfer or sell registered US securities, the transfer agent requires a Medallion Signature Guarantee. This is a special stamp from a financial institution that belongs to the US Securities Transfer Agents Medallion Program (STAMP). It verifies the signer's identity and authority — and a Notary Public or ordinary bank stamp will not be accepted.
Do you need a US ancillary grant?
A US ancillary grant (ancillary probate) is a secondary grant obtained in a US state to deal with assets located there. Whether you need one for US shares depends on how the shares are held and their value, and on the rules of the relevant US state.
In many cases, a US broker or transfer agent will release shares to an Irish estate on the Irish grant of representation, together with the IRS transfer certificate and a Medallion Guarantee, without a separate US grant. Larger or more complex holdings, or assets tied to a particular state's probate rules, may require an ancillary grant in that state.
Because requirements vary by institution and by state, confirm the exact documents the transfer agent needs before assuming an ancillary grant is or is not required. A non-resident executor managing this from Ireland will often coordinate with a US attorney for anything beyond a straightforward release. See our guide for the non-resident executor dealing with an estate.
Step-by-step: dealing with US shares in an Irish estate
These steps assume the person who died was Irish-domiciled and the Irish grant is the primary grant. The US steps run in parallel with the Irish administration, so start the US transfer certificate early.
Identify and value the US shareholding
List every US holding: directly registered shares, brokerage accounts, US-domiciled funds, and any legacy paper certificates. Obtain the date-of-death value of each holding in US dollars. The broker or transfer agent will issue a date-of-death statement on proof of death. You will need these figures for both the US estate tax position and the Irish CAT return.
Obtain the Irish grant of representation
Apply for the primary Irish Grant of Probate— the court's permission to manage the estate — in the normal way. If there is no will, you apply for a Grant of Administration instead, which does the same job. Where the person who died was Irish-domiciled, US-situs shares form part of the worldwide estate you disclose in the Statement of Affairs (Probate) Form SA.2. The Irish grant is the foundation document the US institutions will ask to see.
Assess US federal estate tax exposure
Add the date-of-death value of the US-situs assets to any adjusted taxable gifts (US gifts made since 1977) and the gift tax specific exemption used. Where that total goes above the $60,000 filing threshold, you must file a US estate tax return (Form 706-NA), with tax of up to 40%. This threshold applies to people who were neither US citizens nor US-domiciled. The Ireland–US treaty can affect the charge, so a US estate tax advisor should review the position.
Apply to the IRS for a transfer certificate (Form 5173)
A US broker or transfer agent will not release a non-resident decedent's shares until it receives an IRS transfer certificate (Form 5173) confirming any US estate tax has been satisfied or that none is due. The IRS itself notes this process can take a year or longer, so apply early. Small holdings may qualify for a streamlined release — confirm the institution's threshold.
Arrange a Medallion Signature Guarantee
To transfer or sell registered US securities, the transfer agent requires a Medallion Signature Guarantee on the transfer forms — a stamp from a financial institution in the US Securities Transfer Agents Medallion Program (STAMP). An Irish notary cannot provide this. A small number of Irish and UK banks and specialist firms offer the service; arrange it before submitting transfer paperwork.
Transfer or sell the shares and convert to euro
Once the transfer certificate and Medallion Guarantee are in place, the transfer agent can re-register the shares to the beneficiaries or sell them. Convert dollar proceeds to euro and keep a record of the exchange rate applied — Revenue may query the conversion. Hold the funds in the estate account until all tax obligations are settled.
File the Irish CAT return and claim treaty credit
Each beneficiary files a CAT return (Form IT38) through Revenue's myAccount or ROS where they exceed 80% of their threshold. Claim credit for US estate tax paid on the same shares under the Ireland–US treaty, calculated at the lower of the two effective rates. Keep the US documentation — the claim must be made within six years of the inheritance.
When you need professional help
Estates with US shares almost always benefit from professional help on both sides of the Atlantic. The combination of US estate tax, an IRS transfer certificate, Medallion requirements, and Irish CAT with treaty relief is genuinely technical — and the cost of getting the timing or the credit wrong can be significant.
- US-situs assets, with any US lifetime gifts, above the $60,000 filing threshold (US estate tax filing)
- Uncertainty over whether holdings are US-situs (ADRs, mixed funds)
- Larger holdings that may need a US ancillary grant
- Claiming the treaty credit correctly on the Irish CAT return
- Beneficiaries in different countries with their own tax positions
- Any question about the deceased's domicile
On the Irish side, a solicitor handles the grant and a Chartered Tax Advisor handles the CAT return and treaty credit. On the US side, a US estate tax advisor handles Form 706-NA and the transfer certificate. For what the executor is responsible for overall, see our executor duties guide.