Last updated 31 August 2026.
A cheap portfolio is easy to describe and easy to break. The usual UK shortcuts — an ISA, a SIPP, FSCS language copied from a high-street leaflet — assume one tax residence, one wrapper, and one regulator. This piece is for English-speaking readers who earn, live, and invest in different countries. It is not UK tax advice, and it is not a forecast of returns.
Broker and fund names below are illustrative. Bankrolled has no live affiliate link for any of them, so there is no “sign up here”. Read the fund’s own key information document and the register in the country that actually taxes you.
The first cornerstone in this series was about moving money across borders without a UK bank. This one is about what that money sits in once it is investable.
Three places a tax rule can attach
Cross-border investing has three addresses, and they are not the same.
You. Tax residence (and, for US citizens and green-card holders, US person status) decides whose form you file. The OECD’s Common Reporting Standard is why a broker in Singapore or Ireland will ask where you are resident and then report account data to its local authority for automatic exchange. That is reporting, not a tax rate.
The broker. The firm that holds the account is a financial institution in a jurisdiction. If you are a US person, the Foreign Account Tax Compliance Act (FATCA) is why that institution may need a GIIN and why you may also file Form 8938 for specified foreign financial assets. FATCA is a US reporting statute. It does not make an Irish ETF a US mutual fund.
The fund. Domicile is the country whose fund law the vehicle lives under. A UCITS is an EU collective investment scheme under Directive 2009/65/EC. Ireland is a common UCITS home. The United States has its own registered funds. Buying “the same world index” in two wrappers is not the same legal object.
Name the jurisdiction every time you copy a rule. FSCS deposit protection is a UK scheme for eligible deposits with PRA-authorised banks. It is not a guarantee of your ETF. An ISA is a UK wrapper. If you are not in the UK tax system, do not build the portfolio as if you were.
Fund domicile is not your passport
For a non-US investor, Irish-domiciled UCITS equity funds are the usual cheap building block. One reason is treaty geometry, not marketing. Article 10 of the 1997 United States–Ireland income tax convention limits source-state tax on portfolio dividends to 15% of the gross amount where the beneficial owner is a resident of the other state (as of August 2026, the treaty text on IRS.gov). Irish funds are often used because they are UCITS vehicles resident in a treaty country. Whether a given fund actually qualifies is a fact about that fund. It is not a slogan you can paste onto a Luxembourg lookalike without reading the prospectus.
US statutory withholding on US-source dividends paid to a foreign person is a different, higher default under the Internal Revenue Code. This article does not invent a “best” after-tax yield. It tells you where the 15% cap is written so you can stop treating blog roundups as law.
UCITS share classes are often accumulating or distributing. Accumulating classes reinvest inside the fund. That can be administratively cleaner if your residence does not need a cash dividend. It does not erase tax in a country that taxes deemed income. Distributing classes pay out. Neither class is “tax-free”. Read the KID for ongoing charges rather than copying a TER from a comparison table that will be stale by next quarter. This draft quotes no product fee.
US persons are not everyone else
If you are a US person, a non-US fund is often a passive foreign investment company (PFIC). The IRS instructions for Form 8621 (revised December 2025) define a PFIC as a foreign corporation that meets an income test (75% or more of gross income is passive) or an asset test (at least 50% of assets produce or are held to produce passive income). Many foreign index funds fit that description. A US person who is a shareholder generally files Form 8621 in the circumstances the instructions list, including excess distributions and certain annual reporting under section 1298(f). Excess-distribution tax under section 1291 is not the same as the tax on a US-listed ETF.
The practical split, still as of August 2026, is crude and useful. US persons who want a simple listed portfolio usually stay in US-registered funds at a US broker and accept US estate and reporting rules as the cost of that simplicity. Non-US persons who are not US-taxed usually stay out of US-listed ETFs when an Irish UCITS equivalent exists, because they are not trying to become accidental US estate or withholding problems. That is not tax advice for your facts. It is why “just buy VTI” is a US-person sentence, not a global one.
Costs you can actually read
Three costs matter, and only one of them is on the factsheet.
The fund’s ongoing charges, in the KID or equivalent, as of the document’s date. Do not invent a number here.
Trading costs at the broker: commissions, FX conversion, and the spread on the line you actually click. Those are on the broker’s tariff, not in this article.
Tax drag you cannot see in the TER: withholding inside the fund, your residence tax on dividends or gains, and the reporting burden of the wrong wrapper (PFIC paper for a US person; a local deemed-distribution rule for someone else). Cheap plus the wrong domicile is not cheap.
A default that does not need a UK wrapper
Keep it small enough that you can still explain it after a visa change.
One broad global equity fund and one broad global bond fund, both in a domicile that matches your US-person status, held at a broker that will open and report for your tax residence. Rebalance on a calendar, not a forecast. Hold cash for spending in the payment account from the first cornerstone, not as a pretend bond fund. Do not add a third “smart” product until the first two are funded and you can name the three addresses above without notes.
If a country where you live offers a local pension or savings wrapper (Singapore’s SRS is an example of a local scheme, not a global ISA), treat it as optional and local. It does not replace the brokerage portfolio. It also does not travel when you leave.
What this article is not
It is not a model portfolio with expected returns. It is not an ISA or SIPP explainer. It does not apply FSCS to ETFs. It does not tell you to open a named broker. If a figure is not on a regulator page, a treaty, or the fund’s own document dated 2026, it is not in this draft.
Sources
- IRS — Instructions for Form 8621 (December 2025), PFIC income and asset tests; Form 8621 filing.
- IRS — About Form 8621.
- IRS — Foreign Account Tax Compliance Act (FATCA).
- United States–Ireland income tax convention (1997), Article 10 (dividends; 15% cap on portfolio dividends).
- OECD — Consolidated text of the Common Reporting Standard (2025).
- Directive 2009/65/EC (UCITS).
- ESMA — UCITS interactive single rulebook.
- Bankrolled — Moving money across borders without a UK bank (Earn cornerstone, published).