A US founder moving to London should settle three things before landing: who will really run the Delaware company from then on, which UK tax year the arrival date falls into, and what records and elections cover the founder shares. A few weeks' difference in the landing date can move the end of the four-year regime by a full tax year, and running the company from London can take its dividends outside that regime.
This post is for US citizen founders who have not lived in the UK for at least ten tax years and will keep working on a Delaware corporation after moving. It turns the moving section of our guide to US-UK tax for founders, fund managers and executives into a timeline counted back from arrival. The claim itself is weighed in our post on the FIG regime for US citizens.
What should a founder do before arriving in London
Work backwards from the landing date, because the early steps decide what the later ones can achieve. Company governance needs the longest lead time, since real decision-making cannot be moved overnight. The arrival date comes next, and the share records can be assembled alongside both.
The order and timings below are our suggested framework, not an official sequence, and they carry no legal force. A founder on an urgent move can compress them but should keep the order. Our tax planning service can run the company and personal questions together.
- Twelve months out: list every UK-resident year ever, and count ten clear tax years back from the likely first year
- Nine months out: decide who will hold top-level decisions at the Delaware company after the move
- Six months out: gather share purchase papers, vesting schedules and any section 83(b) election
- Three months out: choose a landing date against the 5 April year end and log every UK night already spent
- One month out: model a share sale before arrival, during the regime and after it
- Landing week: start a dated record of UK nights, UK workdays and where board decisions are made
Does a Delaware company become UK resident when its founder moves to London
It can. A company incorporated outside the UK is UK resident if its central management and control is exercised here, and that is a question of fact. Where a founder makes the decisions that matter, those decisions can arrive with them. Delaware incorporation does not prevent this, and no election switches the test off.
HMRC's manual on central management and control (opens the official HMRC page in a new tab) looks for the highest level of control, which may sit with a board or with a shareholder who has in fact taken over management. Its older handbook guidance (opens the official HMRC page in a new tab) says that where one person holds real power over important decisions and moves country, control may move too. It also treats board meetings that merely confirm decisions taken elsewhere as a form of words. A US board that approves whatever the founder sends from London is weak evidence.
UK residence means Corporation Tax on all profits from the UK and abroad (opens the official GOV.UK page in a new tab), and HMRC's registration guidance for non-UK incorporated companies (opens the official HMRC page in a new tab) sets a limit of three months from the date the company became UK resident. The company does not stop being American: it remains a domestic corporation filing Form 1120 (opens the official IRS page in a new tab). HMRC's migration guidance (opens the official HMRC page in a new tab) adds that the company's assets get no general uplift in base cost on arrival, so growth in its intellectual property before the move can stay within a later UK gain.
How can a founder plan for central management and control before the move
Decide which outcome you are planning for, and change how decisions are actually made to fit it. Either a real board outside the UK will make the top-level decisions, or the company accepts that it will probably be UK resident and prepares for that before the founder arrives.
The US-UK treaty does not settle dual residence automatically for a company. Under Article 4(5) of the 2001 convention (opens the official GOV.UK page in a new tab), the two tax authorities try to agree how the treaty applies. Without agreement, the company generally cannot claim treaty benefits, apart from a short list in Articles 24(4), 25 and 26.
A founder working from London may still give the company a permanent establishment, as our post on a US startup's first UK employee explains. HMRC's guidance gives no safe number of directors or meetings, so the points below are evidence to weigh and depend on the facts.
- Who sets strategy, approves budgets and authorises funding rounds, and from which country
- Whether directors outside the UK have the knowledge and standing to refuse the founder
- Whether the founder holds a voting veto or shareholder powers that decide matters in practice
- What the founder will still decide alone from London, and who can overrule it
How does the arrival date affect the Statutory Residence Test and the four-year clock
The date decides which tax year comes first. Someone who was not UK resident in any of the three previous tax years, and who spends fewer than forty-six days here in a tax year, is automatically non-resident for it. Land later than that cut-off and the next year is the first; land earlier and this year may be.
HMRC's guidance on the Statutory Residence Test (opens the official HMRC page in a new tab) says the automatic overseas tests come first, and the manual confirms that meeting one (opens the official HMRC page in a new tab) settles the year. A day counts if you are here at midnight (opens the official HMRC page in a new tab), subject to transit days. Otherwise, the third automatic UK test can make a founder resident through full-time UK work over a year-long period starting in the year. Case 5 of split-year treatment (opens the official HMRC page in a new tab) may then divide the year. Yet HMRC's manual on the qualifying new resident (opens the official HMRC page in a new tab) says a split year counts as a full year of residence, so a short stub still uses one of the four.
A US citizen founder holding four million shares in a Delaware company has never lived in the UK and will work full time from the day of landing. Land on 1 February 2027 and 2026/27 holds sixty-four midnights, too many for the automatic overseas test. The full-time work test is likely met, the year is probably split, and the regime runs from 2026/27 to 2029/30. Land on 1 March 2027 and there are thirty-six midnights, so 2026/27 is non-resident and the regime runs from 2027/28 to 2030/31.
For a founder expecting an exit in 2030/31, that month decides whether the sale can fall inside a claim. Counting back, 20 February 2027 gives forty-five midnights, provided there were no other UK nights that tax year. A twelve-night scouting trip the previous October would turn a 1 March landing into forty-eight days and lose the automatic test. London salary for those weeks remains UK income for a non-resident (opens the official GOV.UK page in a new tab). Immigration and family may outweigh all this, and the US taxes a citizen on either date.
What does the FIG regime not protect for a US citizen founder
The regime removes UK tax on claimed foreign income and gains. The US still taxes a citizen on worldwide income, UK-source salary stays taxable here, and foreign employment income falls outside it. For a founder, the sharpest gap is that dividends from a company that has become UK resident may not qualify.
HMRC's eligibility guidance (opens the official HMRC page in a new tab) confirms that foreign earnings need a separate relief, overseas workday relief, and that a claim costs the income tax and capital gains allowances. Publication 54 (opens the official IRS page in a new tab) confirms the US position, so a claimed item leaves no UK tax to credit on Form 1116.
HMRC's list of qualifying foreign income (opens the official HMRC page in a new tab) refers to dividends from non-UK resident companies, while qualifying gains (opens the official HMRC page in a new tab) turn on where an asset is situated. Under section 275 of the Taxation of Chargeable Gains Act 1992 (opens the official GOV.UK page in a new tab), registered shares sit where they are registered, and the rule placing shares in the UK is limited to UK-incorporated companies. So a Delaware company that migrates here may pay dividends outside the regime, while a gain on its shares can remain foreign if the register stays abroad. HMRC's guidance does not address this case directly, and a treaty outcome could affect it, so it is a point to confirm on the facts.
What should a founder do with founder shares before arrival
Mostly, establish the facts while the papers are easy to find, then test any transaction against the three possible sale windows. The UK and US compute gains separately, and we found no rule in HMRC's guidance giving an individual a general market-value uplift on arrival, so assume pre-arrival growth can come within UK tax.
Restricted shares need particular care. A section 83(b) election, on Form 15620 (opens the official IRS page in a new tab), must be made within a short fixed period after the transfer and cannot be made late, as our post on growth shares and the 83(b) election explains. HMRC's manual on restricted securities (opens the official HMRC page in a new tab) says the UK rules can apply to shares acquired by a non-UK resident where the related earnings are at least partly within UK tax, and that the separate UK election must be made jointly with the employer within fourteen days of acquisition. It is usually gone by the time a founder arrives.
The Budget announced a Founders' Relief for qualifying disposals from 6 April 2027, but the technical consultation (opens the official HMRC page in a new tab) on its conditions is open until 30 November 2026, so nobody should fix a move or a sale around it yet. Our private client service can test each option on both returns.
- List each tranche with its share count, acquisition date, vesting dates and any election filed
- Record dollar cost and the sterling equivalent at acquisition, since each country measures its own gain
- Confirm where the share register is kept, and do not move it to the UK without advice
- Take advice before a funding round re-imposes vesting on shares close to the move
- Compare a sale before arrival, in a claim year and after the regime ends, on both returns
What filings start once a founder has landed
UK Self Assessment starts first, usually with a residence page and any claim. New filers register by the deadline after the tax year ends. The US return continues without a break, and new UK accounts join the FBAR and Form 8938 counts. Each item is easier to meet when its records begin on the landing date.
The founder registers by 5 October after the first UK tax year. Split-year treatment and regime claims go on the SA109, which needs commercial software or paper, and our UK Self Assessment service files it. On the US side, a filer living abroad has until 15 June to file, although interest still runs from 15 April.
Accounts count for the FBAR, filed with FinCEN once the aggregate exceeds $10,000 at any time in the year, and signature authority over a company account counts as well as ownership. Form 8938 applies above $200,000 at year end or $300,000 at any time for someone abroad not filing jointly. The foreign tax credit often suits UK earners better than the exclusion, and our guide for founders, fund managers and executives sets out the wider picture. To review a planned move, contact us with the proposed date and the company's board papers.
General information, not advice. The right answer depends on your circumstances and the tax year concerned.
