US estate tax on non-residents applies to US-situs assets, and shares of US companies are US-situs regardless of where you hold them. The IRS states it plainly: the rule applies "even if the nonresident held the certificates abroad or registered the certificates in the name of a nominee". Holding VOO at an Asian or European broker changes nothing.
A US citizen dying in 2026 gets a basic exclusion of $15,000,000. A non-resident alien gets a unified credit of $13,000 — which shelters exactly $60,000. Everything above that is taxed on a graduated scale reaching 40 %, and the estate must file Form 706-NA.
A fund domiciled in Ireland is not a US-situs asset, so it sits outside the US estate tax net. It also pays a lower rate on the way in: 15 % withholding at fund level under the Ireland–US treaty, against the full 30 % that applies to a resident of a country with no US income tax treaty. For a UAE or Singapore resident, the Irish route wins on both counts — every year, and at the end.
US citizens and green-card holders abroad face the opposite problem. Irish UCITS are PFICs, triggering Form 8621 per fund per year and an excess-distribution regime that can cost more than the withholding it saves. The correct answer for a US person is usually the one that is wrong for everyone else — which is exactly why generic expat advice is dangerous.