US vs Irish-Domiciled ETFs: Why the After-Tax Answer Depends on Your Client's Tax Residence

Published 21 October 2026 by Borderfolio

"Hold Irish-domiciled ETFs instead of US ones to save withholding tax" is common advice for investors outside the United States. For some clients it is right. For others it reduces what they keep, because their home country would have credited the US withholding anyway. The difference is the client's tax residence, and it is worth working through before a switch is proposed.

Two layers of tax on the same dividend

A US company's dividend paid to a non-US investor can be taxed twice:

• At source, in the United States. Through a US-domiciled ETF, the investor suffers US withholding: the treaty rate of their residence (often 15%) with a W-8BEN on file, or the statutory 30% without one or without a treaty. Through an Irish-domiciled ETF, the fund suffers 15% on its US dividends under the US–Ireland treaty, inside the fund, and Ireland withholds nothing on what the fund pays to non-Irish investors.
• At home, in the residence. Many residences tax dividends and give a credit for foreign tax withheld, usually up to the treaty rate. That credit applies to withholding the investor suffered personally. The 15% lost inside an Irish fund is not the investor's tax and is generally not creditable.

So the Irish structure removes a tax the home country may have refunded through the credit, and replaces it with one it will not refund.

A worked example

Take 1,000 of US-source dividends a year, flat home rates and no allowances. This is illustrative arithmetic, not any country's full rules.

• Home tax 30%, credit for US withholding, W-8BEN on file (15%). US ETF: 1,000 − 150 withheld − 150 home tax after a 150 credit = 700 kept. Irish ETF: 850 paid out − 255 home tax = 595 kept. The switch costs 105 a year.
• The same client without a W-8BEN (30% withheld). The credit still stops at the 15% treaty rate. US ETF: 1,000 − 300 − 150 = 550 kept; Irish ETF: 595. The switch looks better by 45, but filing a W-8BEN takes the US ETF back to 700, without selling anything.
• Home tax 10%, credit, W-8BEN on file. US ETF: 1,000 − 150 − 0 = 850 kept, because the credit covers the home tax; Irish ETF: 850 − 85 = 765. The switch costs 85.
• No home tax on dividends and no US treaty (30%). US ETF: 700 kept; Irish ETF: 850. Here the switch saves 150 a year, the full gross figure.

Only the last case matches the usual advice. Residences that tax fund income under their own investment-fund rules, or tax accumulating funds on deemed income, need those rules applied on top; a flat rate does not capture them.

Then the fees, and the estate question

An Irish counterpart often has a higher TER than the US fund it replaces. A small after-tax gain can be smaller than the extra fee, so a switch should be judged on dividends kept after tax, net of fund fees. Separately, US-domiciled funds are US-situs assets for US estate tax, which applies to non-resident non-citizens above a low threshold (USD 60,000) unless a treaty gives relief. Irish funds are not US-situs. For some clients that is the strongest reason to switch, whatever the dividend arithmetic says.

How Borderfolio for Advisors handles it

• Per holding, after all tax. For each US-domiciled holding the engine works out what the client would keep through an Irish fund, at the chosen residence, with the credit capped at the treaty rate and at the home tax due.
• A tax basis per scenario. Compare at the client's current residence, at a planned move from their relocation plan, or at any residence the engine covers. Rates are the statutory default unless you entered the client's expected rate.
• Regimes as your note. A special regime, such as a new-resident regime, is recorded and printed as your own commentary. Borderfolio does not hold or apply regime rules; it uses the rates shown.
• W-8BEN flagged. When no W-8BEN is on file and the client holds US instruments, the scenario says so before any switch is considered.
• Net of fees. The comparison shows dividends kept after tax and the same figure net of fund fees, current against proposed.

Portfolio proposal scenarios describes the rest of the comparison. Figures are decision support for professional review, not tax advice.

Frequently asked questions

Do Irish-domiciled ETFs always reduce tax for non-US investors?

No. They reduce US withholding, but the 15% suffered inside an Irish fund is generally not creditable at home. Where the residence taxes dividends and credits US withholding up to the treaty rate, a US-domiciled ETF can leave the client with more. Where the residence does not tax dividends, the Irish fund usually keeps more.

What does a W-8BEN change?

With a W-8BEN on file, US withholding drops from the statutory 30% to the residence's treaty rate, often 15%. Home countries generally credit only up to the treaty rate, so without the form the excess is a pure cost. Filing it changes the comparison without selling anything.

Does Borderfolio apply special tax regimes such as new-resident regimes?

No. The adviser records the regime and the rates they expect; Borderfolio calculates with those rates and prints the regime as the adviser's note. It does not hold or apply regime rules.