Pre-immigration movers
Moving to the US soon? The window before you become a US tax resident is the best time to restructure investments, realise gains, and document basis. After arrival, the planning options narrow sharply.
The 12 months before you arrive in the US is the best tax-planning window of your life.
Once you become a US tax resident, the toolkit shrinks. ISAs you've held tax-free for 20 years become PFICs. Property gains crystallise at acquisition cost, not market value. Pension drawdown options narrow. Family trust distributions become reportable events. The pre-immigration window — typically 6-12 months before crossing the substantial presence threshold — is when you can step up basis, restructure investment vehicles, realise gains in the friendlier UK regime, and document everything for the IRS to accept later. Get this right and the first US return is uneventful. Get it wrong and you're catching up for a decade.
- Substantial presence countdown mapped against intended arrival date
- Pre-arrival basis step-ups on UK assets where it makes sense
- ISA and OEIC restructuring before they become PFICs
- Pension drawdown timing across the residency line
- 183days that trigger US tax residency (current year)
- 12 moideal pre-arrival planning window
- $0additional US tax on pre-arrival realised UK gains
- 37%PFIC rate that pre-arrival restructuring avoids
What we look at first.
- Timing your arrival around the substantial presence test
- Pre-immigration basis step-up planning
- Restructuring UK investment vehicles before US residency
- ISA and UK pension decisions pre-arrival
The forms we’ll likely prepare.
- Dual-status 1040 for arrival year
- Planning memos (pre-arrival)
Four steps from intake to filed return.
- 01
Arrival timeline
Confirm intended move date and US residency trigger date. Map the planning runway you have left.
- 02
Asset audit
Walk through ISAs, OEICs, brokerage, pensions, property, family trusts. Identify what should be restructured, sold, or stepped-up before US residency starts.
- 03
Execution plan
Coordinate with UK financial advisers and tax counsel on the order of operations — gift, sell, contribute, liquidate — so each step is clean for both UK and US tax.
- 04
Arrival-year filing
Prepare the dual-status 1040 for the arrival year with all pre-arrival positions documented.
Three months before moving to Boston I was about to liquidate everything 'to keep it simple'. TaxStone pulled the brakes — we restructured the ISA, stepped up basis on a UK property, and arrived with a clean tax position instead of a multi-year cleanup project.
Common mistakes we see — and fix.
These are the four positions that most often get filed wrong before clients come to us. Sometimes it’s a prior preparer’s call we’d disagree with; sometimes it’s a default election that compounded for years. Either way, we work backwards through them before drafting your return.
- Triggering US residency mid-year without realising it
- Liquidating ISAs after arrival, paying ordinary US income tax on every penny of gain
- Missing pre-arrival pension contribution windows
- Failing to document basis step-ups for the IRS to accept later
Three snapshots from our practice.
Anonymised, paraphrased, but representative — three of the shapes the work tends to take for pre-immigration movers.
Founder relocationUK founder moving to San Francisco for a Series B. We restructured a UK Ltd before residency to dodge a Form 5471 trap, stepped up basis on founder shares, and timed the move past July 2 to delay residency.
Property + ISA wind-downCouple moving from Manchester to Boston with two BTL properties and £400k of ISAs. Pre-arrival sale of the ISA wrapper to step up basis, retained property + treaty disclosure on rental income.
Academic + family trustResearcher moving to NIH on a 3-year grant. UK family-trust beneficiary — pre-arrival distribution of the relevant share, post-arrival Form 3520 only for what couldn't be wound down in time.
See if pre-immigration movers describes your situation.
We'll confirm what you need to file — and just as importantly, what you don't.