What changes when you move from New Zealand to the United States?

Can you just go?

No, and there is no shortcut. Australians have a US work visa of their own, the E-3, and New Zealanders do not. What New Zealand does have, since 10 June 2019, is treaty status for the treaty trader and treaty investor visas, E-1 and E-2, on the State Department's list of treaty countries. Those suit people running trade or an investment between the two countries, not most employees. Anything else starts at the State Department, and this guide does not try to choose for you.

1Before you leave New ZealandStudent loan starts charging interest once you're overseas-basedKiwiSaver can come out after a year away, not the government's part

2ArrivingA visa first: no dedicated one for New ZealandersHealth insurance is yours to arrange

3Your first US tax yearResident for tax once you pass 183 days, weighted over 3 yearsThen taxed on worldwide income, KiwiSaver included

4Five years as a green card holderMedicare opens to you, to buy into

5After at least ten years of work40 credits, at most four a year: enough for Social Security

Before you leave New Zealand

You may stay a New Zealand tax resident longer than you think. Inland Revenue only lets you go when you both "do not have a permanent place of abode in New Zealand" and "are away from New Zealand for more than 325 days in any 12-month period". A few people are also caught by a rule for offshore shares and funds: when you become non-resident, "you'll be treated as having sold your interests for market value immediately before the change for the purpose of calculating FIF income."

A student loan stops being interest-free once you are overseas-based, which Inland Revenue puts at "around 5 out of 6 months" away. Interest then runs at 5.6% a year for 2026-27, and repayments are set by the size of the loan rather than your pay.

KiwiSaver can come out, most of it. Emigrating anywhere other than Australia lets you withdraw after you have lived outside New Zealand for a full year, but "You cannot take out the government contributions." Whether to take it is tied up with the next section, because the United States will tax it in its own way whether it stays or comes out.

Your first year in the United States

When the US starts taxing you. A green card makes you resident for tax straight away: "You are a resident, for U.S. federal tax purposes, if you are a lawful permanent resident of the United States at any time during the calendar year." Without one, you are resident once you pass the substantial presence test: "31 days during the current year, and" "183 days during the 3-year period", counting all of this year's days, a third of last year's and a sixth of the year before. "The most common dual-status tax years are the years of arrival and departure", so expect your first year to be split in two.

From then on the US taxes your worldwide income, the way it taxes its citizens. KiwiSaver, New Zealand bank accounts and New Zealand managed funds come with you on to US forms. The FBAR applies once your accounts outside the US together pass $10,000 at any time in the year. And US tax treats many foreign funds as passive foreign investment companies, which the IRS defines by its income and asset tests, not by name. There is no published ruling on whether a New Zealand fund meets them.

Health insurance is yours to arrange. There is no public scheme to join on arrival. "Lawfully present immigrants can get Marketplace coverage and may qualify for the premium tax credit", which is the usual route if a job does not provide cover. Medicare later has conditions of its own: a non-citizen can buy into it only as "An alien lawfully admitted for permanent residence who has resided in the United States continuously for the 5-year period" before, and it is only free of premiums for people who, or whose spouse, "paid Medicare taxes long enough while working", which Medicare puts at generally at least 10 years.

A credit history starts from nothing. Your New Zealand record does not follow you. The Consumer Financial Protection Bureau's suggestions for starting one include a secured card: "You put in an amount of cash, for example $500. Then, you can spend up to that amount on your credit card."

Social Security, without an agreement

The United States has social security agreements with many countries, including Australia, and none with New Zealand. That has two consequences.

Your New Zealand working years do nothing for US Social Security. You need 40 credits to qualify, and a year of work earns at most four, and years elsewhere count as zeros in the average your payment is worked out from.

And if you go home, the payments may not follow you. A New Zealand citizen is paid in New Zealand for six months and then stopped, with no agreement to fall back on. NZ Super, for its part, deducts US Social Security dollar for dollar.

Children born in the United States

A child born overseas to a New Zealand citizen by birth or grant is a New Zealand citizen by descent, and needs registering to get a passport. It passes one generation only: a citizen by descent cannot automatically pass New Zealand citizenship on to their own children born outside New Zealand.

If you go home

US retirement accounts cost more to empty early. Take money from a 401(k) or IRA before 59½ and "Individuals must pay an additional 10% early withdrawal tax unless an exception applies." Once you are no longer a US resident, a plan paying you "must generally withhold 30% of the payment for federal income tax" unless you claim a lower treaty rate.

Keeping US shares has an estate tax edge. After you leave, your estate must file a US estate tax return "if the fair market value at death of the decedent's U.S.-situated assets exceeds $60,000", which includes shares in US companies. The US has an estate and gift tax treaty with Australia, and none with New Zealand.

A long-held green card has an exit rule. You are a long-term resident "if you were a lawful permanent resident of the United States in at least 8 of the last 15 tax years". Giving up that status can bring in the expatriation tax, which applies to anyone whose "net worth is $2 million or more", whose average income tax over the previous five years is above a threshold, or who cannot certify five years of compliance.

What gets easier, and what gets harder

Easier

• Treaty trader and investor visas have been open to New Zealanders since 2019.
• KiwiSaver can come out once you have lived overseas for a year.
• Marketplace health plans are open to lawfully present immigrants.

Harder

• No dedicated work visa, unlike Australians.
• No social security agreement: your New Zealand years don't count, and payments can stop if you go home.
• Health insurance is on you, and Medicare needs 5 years as a permanent resident to buy into.
• KiwiSaver and New Zealand funds sit awkwardly in US tax.
• A credit history starts from nothing.
• Give up a long-held green card and the expatriation tax rules can apply.

What this guide does not tell you

It does not tell you which visa fits you, which is for the State Department and US Citizenship and Immigration Services. It does not work out your US tax, what the tax treaty between the two countries changes, or whether to take KiwiSaver out before you go.

It does not cover state taxes, which differ state by state, or what being born in the US means for a child's citizenship and, later, their taxes. And the one question in the middle of all of it, how the US treats New Zealand managed funds and KiwiSaver as they grow, is one the IRS has never squarely answered.