New Zealand has a treaty but no totalization agreement — so self-employment tax stays.
There is a US–New Zealand income tax treaty, so double income tax is addressable and New Zealand tax is creditable. There is no totalization agreement, which means US self-employment tax at 15.3% applies to net self-employment income with no relief — the exception among Commonwealth postings.
Tax snapshot — New Zealand
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Sources: IRS Publication 54; IRS Publication 901; US–New Zealand income tax treaty (1982, protocol 2008); SSA totalization agreement list; Rev. Proc. 2025-32. Checked 28 August 2026.
What that means on your return
The distinction that matters: a treaty relieves double income tax, a totalization agreement relieves double social security. New Zealand has the first and not the second. Employees are usually comfortable; consultants and contractors pay SECA on top of whatever New Zealand takes.
KiwiSaver is tax-favoured locally, and its US treatment does not follow automatically. PIE funds inside it are commonly PFICs, so the account can generate both reporting and an unfavourable default calculation.
New Zealand's foreign investment fund rules govern how New Zealand taxes your offshore holdings. They have nothing to do with how the US taxes them — Form 8938 and the PFIC rules apply independently, and both regimes can bite the same asset.
If you are in New Zealand as a…
Questions I get about New Zealand
Why do I pay US self-employment tax in New Zealand?
Because there is no totalization agreement between the two countries. The income tax treaty does not reach social security, so 15.3% SECA applies to net self-employment income even when the exclusion or the credit removes the income tax.
How is KiwiSaver treated on my US return?
Not as automatically tax-deferred. The account is reportable, and PIE funds held inside it are commonly PFICs, so the US treatment is usually less favourable than the New Zealand one.
I already pay high tax in New Zealand. Do I still file a US return?
Yes, every year. Citizenship-based taxation does not care what you pay locally. The foreign tax credit usually removes the US liability, but the filing obligation stands, and FBAR and FATCA reporting stand with it.
When is my return due?
15 June, under the automatic extension for filers living abroad. Form 4868 moves it to 15 October, and I file the extension free.
Do I have to file an FBAR for my New Zealand bank account?
If your foreign accounts together passed $10,000 at any point in the year, yes. You can file it free through FinCEN's own system. The non-willful penalty for not filing is $16,536.
I have not filed for several years. What now?
The Streamlined Foreign Offshore Procedures: three returns, six FBARs and Form 14653 certifying non-willfulness. Penalties are waived. Note that the IRS terminated the separate Delinquent FBAR Submission Procedures around 1 July 2026.
Filing from New Zealand this year?
Twenty minutes with the Enrolled Agent who will prepare and sign it. Complete return, $599.
An IRS Enrolled Agent working only on US tax for Americans living abroad. I prepare and sign every return myself — 17 years in practice, 12 of them as an Enrolled Agent.