The Year-End Checklist for Non-U.S. Residents: 12 Things to Settle Before 31 December

Almost everything that goes wrong in cross-border tax is fixed cheaply before 31 December and expensively after it. A treaty form signed before a payment goes out costs nothing; the same form produced in March, after 30 percent has already been withheld, starts a refund claim that can take a year. This is the list we work through with clients in November and December, in the order the deadlines fall.

Why the year-end date matters more than the filing date

A U.S. tax year for an individual, and for most companies, closes on 31 December. The filing happens months later, but almost nothing about the year can be changed once the year has ended. Days spent in the United States are already spent. A payment made without treaty paperwork on file was already taxed at the default rate. An intercompany charge that was never documented was already made.

The filing season is where the year is reported. The last quarter is where it is still being decided.

The twelve

1. Count your days in the United States before you book anything else

Enough days inside the country makes you a U.S. tax resident on your worldwide income, with no visa change and no move. The count runs across three calendar years: every day this year, a third of last year's days, a sixth of the days from the year before. Reach 183 on that weighted total, with at least 31 days in the current year, and you are resident for the year unless something else overrides it.

Part days count as whole days. A flight that lands on the 28th and leaves on the 2nd is six days, not four. Run your own numbers on the residency calculator before you add a holiday trip to the total.

2. If the count is close, decide which exception you are relying on

Meeting the day count does not always end the matter, but the alternatives have their own requirements and their own forms. A closer connection claim needs fewer than 183 days in the current year, a tax home abroad, and stronger ties to another country. A treaty tie-breaker needs a treaty in force with the country you are resident in, and a disclosure filed with the return. Deciding in December which one applies is planning. Deciding in April is a defence.

3. Check the expiry date on every W-8BEN-E you have given, and every one you hold

A W-8 form is not permanent. It generally expires on the last day of the third calendar year after it was signed, which means a form signed in 2023 stops being valid on 31 December 2026. The payer is then required to withhold at the default 30 percent rate on U.S.-source payments until a fresh form arrives.

This is the single most common self-inflicted January problem in this practice. It costs one signature to avoid.

4. Get the treaty paperwork in before the last payment of the year, not after

A reduced treaty rate applies to a payment when the documentation supporting it is already in the payer's hands. Producing it afterwards does not un-withhold the money; it starts a refund process that runs through the payer's annual reporting and, in some cases, through a filed return. If a December payment is coming, the form belongs in the file in November.

5. Document what your companies charged each other

Management fees, licence fees, service charges, loans between a foreign parent and its U.S. company: each has to look like a charge between unrelated parties, and has to be supported by something written. The record is expected to exist by the time the return is filed, not to be assembled when someone asks for it. December is when the year's intercompany activity is still recent enough to describe accurately.

6. Reconcile the transactions your U.S. company had with its owner

A foreign-owned U.S. company reports its transactions with its foreign owner and with related businesses on an annual information return. Capital put in, money taken out, loans, services, and payments made on each other's behalf all belong on it. The penalty for not filing starts at $25,000 and repeats for each year, which makes this the most expensive box on the form to leave empty.

7. Decide whether anything needs to be distributed, paid or written off this year

A dividend paid on 30 December falls in this tax year; the same dividend on 2 January falls in the next one, with a year's difference in when the withholding is reported and when the cash is taxed at the other end. Bad debts, bonuses and management charges are the same. This is ordinary timing, and it only exists as a choice while the year is open.

8. Look at what is sitting in a U.S. warehouse right now

Inventory held in the United States over the peak season, staff or contractors working here, and an agent with authority to conclude contracts are the facts that decide whether a business is taxed here at all. Q4 is when those facts are at their highest for anyone selling into the country, and the position is measured on what actually happened, not on what the business calls itself. What peak season does to a seller's position covers this in detail.

9. Fix the filings that were missed in earlier years, before a notice arrives

There are established routes for late international filings, and the one that fits depends on the facts and on whether the failure was reasonable in the circumstances. Every one of those routes is easier to use while nobody has written to you. Once a notice is issued, the options narrow and the clock is someone else's.

10. Confirm who you are paying, and on what paperwork

A contractor in the United States gets one form; a contractor outside it gets a different one, and possibly withholding. Collecting the right form from each person you paid this year is a January task that is far easier in December, while people still answer email and before the reporting deadline arrives.

11. If you own U.S. property, decide the position for the year

Rental income from U.S. real estate can be taxed on the gross rent or, by election, on the net profit after expenses and depreciation. The two produce very different numbers. If a sale is planned, the withholding that applies to the price rather than the gain can often be reduced before closing, but only by applying in advance.

12. Put the next four deadlines in the calendar before the holidays

January and February are short months with hard dates in them. The table below is the one we work to for a calendar-year taxpayer.

Key dates after this year-end

Date	What falls due	Who it applies to
31 December 2026	The tax year closes. W-8 forms signed in 2023 expire.	Everyone
15 January 2027	Final estimated tax payment for 2026	Individuals paying estimated tax
1 February 2027	Contractor and wage statements to recipients (31 January falls on a Sunday)	Anyone who paid U.S. contractors or staff
15 March 2027	Partnership returns; annual withholding returns and the statements that go with them	Partnerships; anyone who withheld on payments to foreign persons
15 April 2027	Corporate returns, the foreign-owner information return, foreign account reports, and individual returns where wages were subject to withholding	Companies; most individuals
15 June 2027	Individual returns with no wages subject to withholding; returns for foreign corporations without a U.S. office	Non-residents filing personally

Dates move when they fall on a weekend or a federal holiday, and extensions exist for most of these. An extension moves the filing date; it does not move the date tax is due.

What this list is not

It is not advice on your situation, and it is not complete for every structure. It is the sequence that catches the expensive, ordinary mistakes: the expired form, the undocumented charge, the day count nobody ran, the filing that was missed three years ago and has been quietly compounding since.

If you want the structural version of this rather than the calendar version, the diagnostic takes about four minutes and reads the exposure sitting in your current setup.