US UK Tax Returns Preparation for Angels in US Startups

For a UK-resident American angel, a US startup exit, a write-off and a SAFE conversion each have to be reported twice, once to the IRS and once to HMRC, and the two systems rarely agree. A gain the IRS excludes under section 1202 can still carry full UK Capital Gains Tax, with no US tax to credit against it.

That mismatch is why US UK Tax returns preparation for an active angel portfolio is its own discipline. It is not a routine Form 1040 with a Self Assessment return bolted on. This guide sets out, event by event, how each typical outcome of a US startup investment (Delaware C-corporation shares, SAFEs and convertible notes) is reported on both returns. It also covers where the two regimes diverge, and how to put things right if earlier years were filed incompletely. It is written for preparation and compliance. It does not recommend investments or structures.

Why angel investing from the UK creates two different tax answers

A US citizen living in the UK is taxed by the IRS on worldwide income and gains because of citizenship. The same person is taxed by HMRC as a UK resident. Under the US-UK income tax treaty, gains on shares are generally taxable in the country of residence. The "saving clause", however, lets the US keep taxing its own citizens as though the treaty did not exist. The treaty then decides which country gives up tax through a credit. For most share gains realised by a UK resident, the UK has the primary right to tax, and the US gives relief for the UK tax on the US return.

That arrangement works well when both countries tax the same gain at similar rates. It breaks down when one side grants a relief the other does not recognise. Angel investing is full of such reliefs: the US has the qualified small business stock exclusion and ordinary-loss treatment for small business stock, and the UK has EIS, SEIS and Investors' Relief. Almost none of them carry across the Atlantic. The outcome is a portfolio in which the same event can be exempt in one country and fully taxable in the other, or deductible against salary in one and only against gains in the other.

What the leading guides tend to miss

Most published material on this topic looks at one country only. It either explains QSBS for US founders or explains EIS for UK investors. The cross-border commentary that does exist often predates two major changes. First, the UK abolished the remittance basis from 6 April 2025 and replaced it with a residence-based regime, so "keep the proceeds offshore" no longer shelters gains for most long-term residents. Second, the 2025 US legislation reshaped section 1202 for stock issued after 4 July 2025. Both changes affect how an exit should be reported today.

Scenario 1: a successful exit and the QSBS mismatch

How section 1202 works on the US return

Section 1202 lets a non-corporate shareholder exclude some or all of the gain on the sale of qualified small business stock. The stock must be original-issue shares in a domestic C-corporation that met an aggregate gross assets test when the shares were issued and that ran a qualifying active business for substantially all of the holding period. The rules now depend on when the stock was issued:

• Stock issued before 5 July 2025 (and, for full exclusion, after 27 September 2010): a five-year holding period for any exclusion, a 100% exclusion, a gross assets limit of $50 million at issuance, and a per-issuer cap equal to the greater of $10 million or ten times the adjusted basis of the stock sold.
• Stock issued after 4 July 2025: a tiered exclusion of 50% after three years, 75% after four years and 100% after five years. The per-issuer cap rises to $15 million, with inflation indexing scheduled from 2027, and the gross assets limit rises to $75 million.

The excluded gain is still reported. It appears on Form 8949 with the sale, and the exclusion is shown as an adjustment to that gain. The IRS instructions for Form 8949 set out the adjustment code. Each qualification condition should be supported by documents kept on file: the original issue date, what was paid, the company's gross assets at issuance, and evidence of an active business. The company's own QSBS representation is useful, but it is not a guarantee.

Where only a partial exclusion applies, as with post-July 2025 stock sold after three or four years, the non-excluded portion is taxed at a 28% rate rather than the usual long-term capital gains rates. The 3.8% Net Investment Income Tax may also apply to that portion. On the IRS's stated position, foreign tax credits generally cannot reduce the Net Investment Income Tax.

How HMRC sees the same sale

HMRC does not recognise section 1202. For a UK resident, the disposal of shares in a US company is a chargeable disposal like any other. The gain is worked out in sterling (explained below) and reported on the capital gains pages of the Self Assessment return. For disposals from 30 October 2024 the main rates are 18% and 24%, according to the individual's income. HMRC publishes the current rates on its Capital Gains Tax rates page. The annual exempt amount is now small (£3,000), so a meaningful exit is almost entirely taxable.

The credit problem, in plain terms

Foreign tax credits work by setting tax paid in one country against tax due in the other on the same income. If the US excludes 100% of the gain, there is no US tax on it. The UK then has nothing to credit, because under the treaty the UK has the primary right and was never going to give a credit here anyway. The US has nothing to relieve, because there is no US liability. The practical result is that the investor pays full UK CGT and no US federal tax. The QSBS exclusion saves US tax that the UK charge would largely have removed through the credit in any event.

Two consequences follow for the preparer:

• Unused UK tax. The UK tax paid on a QSBS-excluded gain generally cannot be used on the US return in that year, because there is no US tax on the gain for it to offset. Depending on how the foreign tax credit limitation works out, some of it may carry back one year or forward up to ten years in the relevant category. It should be tracked properly on Form 1116 rather than simply dropped.
• Partial exclusions. Where the US taxes part of the gain, the UK tax on that part can usually be credited. The foreign tax credit calculation must allocate the UK tax between the taxed and excluded portions. This is one of the most common errors we see on prior-year returns.

Is the old "remittance basis" answer still available?

Older commentary suggested that a US citizen on the UK remittance basis could have both a QSBS exclusion and no UK tax, provided the proceeds stayed outside the UK. The remittance basis ended on 5 April 2025. It has been replaced by a four-year foreign income and gains regime, open only to individuals in their first four tax years of UK residence after at least ten consecutive years of non-residence. A newly arrived American angel who qualifies and makes the claim may still find US-company gains outside UK tax during that window. A long-term resident cannot. Anyone whose earlier returns relied on the remittance basis should check how the transitional rules, including the temporary repatriation facility, affect pre-April 2025 gains that have not yet been remitted.

Scenario 2: a failed investment and the loss mismatch

US: section 1244 ordinary loss, with limits

On the US side, a loss on worthless stock is normally a capital loss. It is treated as arising on the last day of the tax year in which the stock became wholly worthless, and it offsets capital gains plus up to $3,000 of ordinary income each year. Section 1244 can turn it into an ordinary loss, which offsets salary or other income without that cap, but only within tight limits:

• the stock must have been issued by a domestic corporation directly to the individual in exchange for money or property (secondary purchases do not qualify);
• the corporation must have been a "small business corporation" when the stock was issued, broadly with $1 million or less of capital received for stock;
• the company must have derived most of its receipts from active business operations rather than passive income over the relevant period;
• the ordinary loss is capped at $50,000 a year, or $100,000 on a joint return, and any excess is a capital loss.

Many venture-backed companies exceed the $1 million capitalisation test by the time of a priced round. Stock acquired on conversion of a SAFE or note also needs careful analysis. The section 1244 part of the loss is reported on Form 4797, and the balance on Form 8949. Because worthlessness is fixed in a particular year, the US has a special seven-year period for amending a return to claim a bad-debt or worthless-security loss that was missed.

UK: the negligible value claim

HMRC does not treat a company's failure as a disposal on its own. Unless the company is formally dissolved, the investor usually needs a negligible value claim under section 24 of the Taxation of Chargeable Gains Act 1992. The claim treats the shares as sold and reacquired at their negligible value, which creates an allowable capital loss. The claim can be backdated to a time when the shares were already of negligible value, but no earlier than the start of the tax year two years before the tax year in which the claim is made. HMRC's helpsheet HS286 explains the mechanics.

Income tax share loss relief, which lets a capital loss on subscribed shares be set against income, does exist in the UK. It depends on the company meeting qualifying trading company conditions that closely follow the EIS rules. US startups often fail them. The conditions should be tested company by company, not assumed.

Timing, which catches people out

The US year of worthlessness is a question of fact. The UK loss arises on the date the negligible value claim specifies. With different tax years (calendar year against 6 April to 5 April) and different triggers, the same failed company can produce a US loss in one year and a UK loss in another. Both should be matched to gains in the correct period. Failing to make a UK claim in time is common, and the loss is then lost for good.

Scenario 3: SAFEs and convertible notes

SAFEs on the US return

The US has no single codified treatment of a SAFE. The common view treats a standard post-money SAFE as an equity-like instrument or a prepaid forward contract, not as debt. On that view, buying the SAFE is not taxable, conversion into preferred stock is usually not taxable, and the basis of the shares received equals the amount paid. The QSBS holding period is the real point of uncertainty. Many practitioners start it on conversion, when stock is actually issued. Some argue that an equity-like SAFE lets the period start earlier. The position taken should be written down and applied consistently.

SAFEs on the UK return: genuinely uncertain

UK legislation does not refer to SAFEs. For an individual, a SAFE is likely to be a chargeable asset for CGT. It is probably not a share or a loan. The open question is whether conversion is a disposal of the SAFE for shares, and if so whether the reorganisation or conversion-of-securities rules can apply so that no gain arises. In practice, many conversions produce shares worth roughly the amount invested, so little turns on it. Where a discount or cap produces shares worth far more than the investment, however, the point can matter. The UK position should be settled and documented when the conversion happens, not when the shares are later sold.

Convertible notes

A convertible note is debt on both sides of the Atlantic. In the US, interest accrues under the original issue discount or stated-interest rules and is taxable even if it converts rather than being paid in cash. Conversion of the principal into stock is generally not a taxable event, and the QSBS holding period normally starts only at conversion. In the UK, interest is taxed as savings income when it is paid or credited, which includes interest satisfied in shares. The conversion itself may be covered by the conversion-of-securities rule in section 132 of the 1992 Act, depending on the note's terms. Because the note is debt, the investor will not qualify for EIS or SEIS on it.

Why EIS and SEIS relief do not apply to US companies

The Enterprise Investment Scheme and Seed Enterprise Investment Scheme give UK income tax relief, CGT exemption, deferral and loss relief. They require the issuing company to have a permanent establishment in the UK and to meet other conditions on its trade, size and independence. A US C-corporation with no UK operations fails that test, and a SAFE or note is not an eligible share anyway. No EIS or SEIS claim can be made on a typical US angel investment. If a prior-year return did claim one, it needs correcting.

Investors' Relief is a separate UK relief for new ordinary shares in unlisted trading companies held for three years. It does not have the same UK-establishment rule, but its conditions still apply, and its value has fallen sharply. The lifetime limit was cut to £1 million for disposals from 30 October 2024, and the rate rises to 18% from 6 April 2026. For many angels it now gives little or no advantage over the standard rates.

US versus UK: how each event is reported

Event	US return (IRS)	UK return (HMRC)
Exit of qualifying C-corp shares	Section 1202 exclusion (full or partial, depending on issue date and holding period); Form 8949 with adjustment	Fully chargeable to CGT at 18% or 24%; no recognition of QSBS
Exit of non-qualifying shares	Long-term or short-term capital gain; credit for UK CGT via Form 1116	Chargeable gain; UK has primary taxing right on share gains of a UK resident
Company fails	Worthless stock loss; section 1244 ordinary loss up to $50,000 / $100,000 if conditions met; Form 4797	Negligible value claim for a capital loss; income tax share loss relief only if strict conditions met
SAFE converts	Usually no tax; basis = amount paid; QSBS holding period typically from conversion	No specific rules; treatment of conversion should be analysed and documented
Convertible note converts	Accrued interest taxable; principal conversion generally tax-free	Interest taxed as savings income; conversion may fall within s132 TCGA 1992
Currency	Everything in US dollars	Cost and proceeds each translated to sterling at their own dates
Upfront incentives	None for the investor at purchase	No EIS/SEIS for US companies without a UK permanent establishment

Basis tracking: dollars versus sterling base cost

For US purposes the investor's basis is the dollar amount invested, adjusted for later events. For UK purposes the base cost is that dollar amount converted to sterling at the exchange rate on the acquisition date. Proceeds are converted at the rate on the disposal date. The UK gain therefore includes currency movement. A company that exits at exactly the dollar price paid can still produce a taxable UK gain if sterling has weakened, or a UK loss if it has strengthened.

In practice, the ledger for each position should record:

• the instrument (common, preferred, SAFE, note), the issuer and whether it was acquired at original issue;
• each funding date, the dollar amount and the sterling equivalent on that date;
• conversion dates, share classes and share counts received;
• the issuer's QSBS representation and the gross assets evidence at each issuance;
• any section 1244 eligibility evidence;
• secondary sales, partial redemptions, tender offers and escrow or earn-out receipts, each with its own exchange rate.

Earn-outs and escrow holdbacks need particular care. The US generally uses installment or open-transaction rules. The UK usually brings the value of a contingent right into the disposal and then treats later receipts as a separate disposal of that right. The same acquisition payment can produce different figures in different years on each return.

State tax: the QSBS exclusion does not always follow

States decide for themselves whether to follow section 1202. Some, notably California, do not, so a gain excluded federally can be fully taxable at state level. For a UK-resident American this turns on whether any state still treats the investor as resident or domiciled. Someone who moved to London but kept a home, a driver's licence, voter registration or family in a high-tax state may still be exposed to state income tax on a worldwide gain. The UK gives no credit for US state tax where the UK has the primary right. Establishing the state position in writing before an exit year is filed is basic compliance, not planning.

Form 8938 and FBAR: are startup shares foreign assets?

For a US citizen, shares in a US corporation held directly are generally not a "specified foreign financial asset" for Form 8938. Nor are they a foreign financial account for the FBAR. A SAFE or note issued by a US company is likewise a domestic asset. The picture changes when the holding sits in the wrong kind of wrapper:

• Non-US nominee or platform accounts. If US startup shares are held through a UK or other non-US nominee, syndicate vehicle or investment platform, the investor may have an interest in a foreign financial account or in a foreign entity. The account can then count toward the FBAR's $10,000 aggregate threshold and the Form 8938 thresholds, which for a single filer living abroad are more than $200,000 at year end or $300,000 at any time in the year.
• Non-US feeder entities. An interest in a non-US partnership or company that holds the US shares is itself a foreign asset. Depending on the level of ownership, it may also trigger Form 8865 or Form 5471. For a non-US corporation, passive foreign investment company reporting on Form 8621 may apply as well.
• Sterling cash awaiting deployment. The UK bank or brokerage accounts that fund or receive investments are foreign accounts in the usual way.

The IRS's FBAR guidance and the Form 8938 instructions are the starting point. The facts of each holding structure decide the answer, so every vehicle in the portfolio should be classified, not just the direct holdings.

How do you catch up on missed UK disposals and US returns?

Missed UK disposals

Exits in US companies are offshore gains from HMRC's point of view, and angels frequently leave them off the UK return in the mistaken belief that "the US has already dealt with it". This is especially common where QSBS meant there was no US tax. The usual route to correct offshore gains is the Worldwide Disclosure Facility. The assessment window depends on behaviour: generally four years where the taxpayer took reasonable care, six where they were careless, and longer for offshore matters and deliberate conduct. A disclosure made before HMRC opens an enquiry normally attracts the lowest penalties. Missing negligible value claims and loss claims should be reviewed at the same time. Losses reported late can still reduce the tax due on the gains being disclosed, within time limits.

Missed US returns and information forms

A US citizen who has not filed, or who filed without reporting foreign accounts and entities, can usually use the IRS streamlined procedures where the failure was non-wilful. For a person living abroad, the Streamlined Foreign Offshore Procedures require three years of amended or delinquent federal returns and six years of FBARs, with a certification of non-wilful conduct. Where the eligibility conditions are met, no miscellaneous offshore penalty is charged. The IRS sets out the conditions on its streamlined filing compliance procedures page. Angels are often surprised to learn that QSBS-excluded exits still had to be reported. Filing the return late does not in itself remove the exclusion, but the documentary support for it needs to be gathered.

Sequencing the two catch-ups

The UK figures usually need to be settled first. UK tax is the creditable tax on the US return, so final UK liabilities feed the Form 1116 calculations in the streamlined submission. The reverse also applies: US amendments can change the section 1244 or worthlessness year, which may affect when UK loss claims should be backdated to. Preparing both at once, from one reconciled ledger, avoids submitting inconsistent figures to two tax authorities.

A practical preparation checklist for angel portfolios

• Build one position ledger in dollars and sterling, reconciled to cap-table statements and closing documents.
• Classify each instrument (share, SAFE, note) and each holding route (direct, nominee, feeder vehicle).
• For each exit, confirm QSBS status by issue date and apply the correct exclusion tier, the cap and the 28% rate on any non-excluded portion.
• Calculate the UK gain separately in sterling and apply the annual exempt amount and any available losses.
• Run Form 1116 with the correct allocation of UK tax between excluded and taxed gain, and track any carryovers.
• For failures, decide the US worthlessness year, test section 1244, and make and date the UK negligible value claim.
• Check state residency before claiming that no state tax is due.
• Complete FBAR and Form 8938 by reference to the holding route, not the underlying company.
• Remove any EIS or SEIS claims on US companies from prior-year UK returns.

How Jungle Tax prepares both returns together

Jungle Tax prepares US and UK returns side by side for angels, founders and executives whose portfolios cross the Atlantic. We reconcile the two ledgers, document the QSBS and section 1244 positions, make the HMRC loss claims in time, and bring prior years up to date where exits or failures were missed. Our US-UK tax accountants work from a single set of figures, so the credit calculations on each return are consistent. Where the wider portfolio also needs coordinated reporting, our cross-border tax team handles the compliance interaction across both systems. Our work is preparation and compliance, not investment or structuring advice.

If you have exited, written off or converted a US startup holding while living in the UK, or you suspect an earlier return missed one, contact our cross-border team for a confidential consultation. We will review your position ledger, identify what each return needs, and give you a clear, fixed-scope plan to file both correctly.