Does Form 5471 really require US GAAP if my UK company only files FRS 102 accounts?

Yes. The Instructions for Form 5471 require Schedule C to report information in the foreign corporation's functional currency in accordance with US GAAP, and Schedule F to report in US dollars translated using US GAAP translation rules. FRS 102 accounts filed at Companies House satisfy UK company law but are not US GAAP. A conversion is needed, though Regulations section 1.964-1(a)(2) limits the required adjustments to material ones.

My UK company files FRS 105 micro-entity accounts. Is that enough for the return?

No, and it is the hardest starting point. FRS 105 recognises no deferred tax and removes the accounting choices in FRS 102, and the accounts filed at Companies House are heavily reduced, frequently with no profit and loss account on the public register. Schedule C therefore cannot be populated from the filing. The conversion has to be rebuilt from the underlying trial balance and the UK accountant's year-end working papers.

Should I convert to US GAAP first or translate sterling into dollars first?

Convert the accounting framework first, in sterling, then translate the resulting US GAAP figures into dollars. Translation applies different rates to income statement and balance sheet items, so making US GAAP adjustments after translation forces a separate rate decision for every adjustment and leaves the cumulative translation account unreconcilable. Framework first, currency second, produces a bridge that ties cleanly to both the UK accounts and the return.

Do the FRS 102 Periodic Review 2024 changes make the conversion easier?

Structurally yes, operationally not at first. The FRC's Periodic Review 2024 amendments introduce a new Section 20 bringing most lessee leases on balance sheet as a right-of-use asset and liability, and a rewritten Section 23 revenue model, with a principal effective date of accounting periods beginning on or after 1 January 2026. That narrows the recurring gap with ASC 842, but the transition year needs a longer reconciliation because the UK starting point itself changes.

Can I tick the alternative information box and file the UK GAAP numbers instead?

Almost certainly not if you control the company. Item G code 03 covers audited local-country GAAP statements, but the instructions allow a code only where information under any preceding code is not readily available, and the Rev. Proc. 2019-40 safe harbours are written for unrelated section 958(a) shareholders and unrelated constructive shareholders of foreign-controlled corporations. A US founder who owns and controls a UK company falls outside that population.

Form 5471 FRS 102 US GAAP: Converting UK Accounts

Q: How material does a difference have to be before I have to adjust for it?

Regulations section 1.964-1(a)(2) states that no conforming adjustment is required unless it is material, and names the factors that decide it: the amount of the adjustment, its size relative to the corporation's total assets and annual profit or loss, the consistency with which the practice has been applied, and whether the item is recurring or non-recurring. Document the items you conclude are immaterial as well as those you adjust.

Form 5471 FRS 102 US GAAP conversion is the step most US owners of UK companies skip entirely, and it is the step that quietly breaks the rest of the return. The instructions to Form 5471 require the foreign corporation's income statement to be reported in the functional currency in accordance with US generally accepted accounting principles, and require the balance sheet to be reported in US dollars translated using US GAAP translation rules. A UK limited company does not keep its books that way. It keeps them under FRS 102, or under FRS 105 if it qualifies as a micro-entity, because that is what the Companies Act and the Financial Reporting Council require of it. Those are two different accounting frameworks, and moving between them is a separate exercise from converting sterling into dollars.

This is not the same subject as functional currency reporting, and it is not the same subject as filling in Schedule C or Schedule F. Those are downstream problems. The prior problem, the one that determines whether the downstream numbers can ever be reconciled, is the accounting framework itself. In the returns we prepare for founders and shareholders with UK operating companies, the conversion schedule bridging the filed statutory accounts to the figures on the return is the single document that decides whether an examination is a conversation or an argument.

What do the Form 5471 instructions actually say about US GAAP?

The wording matters, so it is worth reading it precisely rather than paraphrasing it. The Instructions for Form 5471 (Rev. December 2025), published at https://www.irs.gov/pub/irs-pdf/i5471.pdf and mirrored in HTML at https://www.irs.gov/instructions/i5471, open the Schedule C section with a single sentence: report all information in the foreign corporation's functional currency in accordance with US GAAP and translate using US GAAP translation principles. The Schedule F section is equally short: report all information in US dollars, and generally the foreign corporation's balance sheet is prepared in functional currency and translated to US dollars using US GAAP translation rules.

Two instructions, two sentences, and an enormous amount of work hidden inside them. Notice that the US GAAP requirement is not a general aspiration. It is embedded at line level throughout the form, which you can see on the form itself at https://www.irs.gov/pub/irs-pdf/f5471.pdf in black and white. Schedule C line 20 tells you that the term unusual or infrequently occurring items is defined by US GAAP, pointing to ASC Topic 220, Subtopic 220-20. Schedule C line 21 tells you to enter income tax expense or benefit reported in accordance with US GAAP under ASC 740, including current and deferred income tax expense or benefit. Schedule F lines 3 and 17 tell you to report derivative assets and liabilities in accordance with ASC 815 and not to net positions.

Read those three together and the point becomes concrete. A UK micro-entity reporting under FRS 105 recognises no deferred tax at all. Schedule C line 21 asks for an ASC 740 number that includes deferred tax. There is no version of that filing where the FRS 105 figure can simply be copied across. The framework difference is not cosmetic; it is the reason the box cannot be filled from the statutory accounts.

What does 'in accordance with US GAAP' realistically demand of a small UK company?

The underlying authority is Regulations section 1.964-1, available at https://www.law.cornell.edu/cfr/text/26/1.964-1, and it is more forgiving and more structured than the bare instruction suggests. Paragraph (a)(1) sets out three sequential steps: prepare a profit and loss statement for the year from the books of account regularly maintained by the corporation for the purpose of accounting to its shareholders; make the adjustments necessary to conform that statement to the accounting principles described in paragraph (b), which is US GAAP; then make the further adjustments necessary to conform it to the US tax accounting standards described in paragraph (c).

That first step is the sentence UK owners consistently miss. The regulation does not ask you to invent a parallel set of US books. It starts from the books of account regularly maintained for accounting to shareholders, which for a UK company is the nominal ledger that produced the FRS 102 or FRS 105 statutory accounts. The starting point is legitimate. What follows is a conforming exercise, not a reconstruction.

The second sentence UK owners miss is paragraph (a)(2), and it is the most useful sentence in the entire regulation for an owner-managed business: no adjustment shall be required under paragraph (a)(1)(ii) or (iii) unless it is material. The regulation then names the factors that decide materiality, which is what makes it defensible rather than a matter of taste. Those factors are the amount of the adjustment, its size relative to the general level of the corporation's total assets and annual profit or loss, the consistency with which the practice has been applied, and whether the item to which the adjustment relates is recurring or merely non-recurring.

In practical terms, a proportionate conversion for a UK company with a few million pounds of turnover looks like this:

List every FRS 102 or FRS 105 accounting policy actually applied in the statutory accounts, taken from the accounting policies note or, where there is no note, from the accountant's working papers.
For each policy, state the US GAAP treatment and whether it differs in principle.
For each difference in principle, quantify the effect on profit and on net assets for the year, even roughly.
Apply the four materiality factors from Regulations section 1.964-1(a)(2) to each quantified difference and record the conclusion.
Adjust the material ones, document the immaterial ones, and apply the same conclusions consistently in the following year rather than re-deciding them annually.

The documentation of the immaterial differences is not busywork. Consistency of application is one of the named materiality factors, so a schedule showing that you considered an item, measured it and concluded it was immaterial is worth considerably more on examination than a clean set of numbers with no visible reasoning behind them.

Why is an FRS 105 micro-entity the hardest starting point?

FRS 105 is the Financial Reporting Council's standard for companies qualifying under the micro-entities regime, described at https://www.frc.org.uk/library/standards-codes-policy/accounting-and-reporting/uk-accounting-standards/frs-105/ on the regulator's own site. It is deliberately minimal. A micro-entity prepares a balance sheet and a profit and loss account and nothing else, the accounting policy choices available in FRS 102 are removed, and deferred tax and equity-settled share-based payment amounts are simply not recognised. That is a perfectly proper UK filing. It is also, from a US reporting perspective, an accounting framework that has deleted several of the very numbers Form 5471 asks for.

The filing position compounds it. Companies House guidance at https://www.gov.uk/government/publications/life-of-a-company-annual-requirements/life-of-a-company-part-1-accounts confirms that a company meeting at least two of the micro-entity conditions from 6 April 2025, being turnover of no more than 1 million pounds, a balance sheet total of no more than 500,000 pounds and no more than 10 employees on average, may file greatly reduced information. The previous thresholds, applying from 30 September 2013 to 5 April 2025, were 632,000 pounds, 316,000 pounds and 10 employees. GOV.UK's overview at https://www.gov.uk/annual-accounts/microentities-small-and-dormant-companies makes the same point from the other direction: micro-entities can prepare simpler accounts meeting statutory minimum requirements and send only a balance sheet with reduced information to the register.

So the document sitting on the public register frequently contains no profit and loss account at all. It cannot populate Schedule C, because the information needed for Schedule C was never published. The conversion has to be rebuilt from the underlying trial balance and the accountant's working papers, not from the filed accounts. In practice that means going back to the UK accountant for the full year-end file rather than downloading the PDF from the register and hoping.

One forward-looking point that will change this landscape: Companies House has confirmed that from 1 April 2028 a micro-entity must prepare and deliver a copy of its profit and loss account, though it will have the option to opt out of publishing that account on the public register, and that from the same date companies will no longer be able to file abridged accounts. For US filers this eventually improves the raw material available, but it does not change the framework problem. A profit and loss account prepared under FRS 105 is still not a US GAAP income statement.

The full nominal ledger trial balance at the year end, not the filleted filing.
The accountant's year-end journals, including any fixed asset, accrual and prepayment schedules.
The fixed asset register showing original cost, additions, disposals and the depreciation policy applied.
Any lease or hire purchase agreements, with commencement dates and terms.
Details of any capitalised development expenditure, acquired goodwill or other intangibles, with original cost and amortisation to date.
The corporation tax computation, which is where UK capital allowances and disallowed items become visible.

Which FRS 102 and US GAAP differences actually change the numbers?

Not every textbook difference matters for an owner-managed UK company. The ones that recur in real files, and that actually move profit or net assets rather than just presentation, are a short list. FRS 102 itself is described by the FRC at https://www.frc.org.uk/library/standards-codes-policy/accounting-and-reporting/uk-accounting-standards/frs-102-the-financial-reporting-standard-applicable-in-the-uk-and-republic-of-ireland/ as the single financial reporting standard for entities not applying adopted IFRS, FRS 101 or FRS 105. Within it, these are the areas that generate conversion adjustments:

Capitalised development costs and the US treatment of research and development.
Goodwill and other intangibles, where the amortisation and impairment models diverge sharply.
Lease accounting, which is moving under the FRS 102 Periodic Review 2024 amendments.
Revenue recognition timing, also rewritten by the Periodic Review 2024 amendments.
Holiday pay and other short-term employee benefit accruals.
Deferred tax, where the measurement approach is conceptually different.
Investment property, where FRS 102 uses fair value and US GAAP generally does not.
Financial instruments, including director loans on non-market terms and derivatives.

How do development costs and research and development diverge?

This is the difference that most often produces a large adjustment in a UK technology or product company. Under FRS 102 a company has an accounting policy choice: development expenditure meeting the recognition criteria may be capitalised as an intangible asset and amortised, or it may be written off as incurred. Many UK owner-managed companies capitalise, because it flatters the balance sheet and supports covenant headroom and valuation discussions. US GAAP under ASC 730 takes the opposite default position and generally requires research and development costs to be expensed as incurred, with narrow exceptions such as certain internal-use software costs under ASC 350-40.

The conversion consequence is direct. Capitalised development expenditure that sits on the FRS 102 balance sheet generally comes off on conversion, the current-year addition is expensed, and the amortisation charge that was reducing FRS 102 profit is reversed. The net effect on profit depends entirely on whether the company capitalised more this year than it amortised. In a growing company it almost always reduces US GAAP profit relative to the UK figure, sometimes substantially, and it reduces net assets on Schedule F. Owners who have been quietly comfortable because their UK accounts show a healthy retained earnings figure are frequently surprised by the restated position, and the surprise is worth having before the return is filed rather than after.

What happens to goodwill and intangibles on conversion?

FRS 102 amortises goodwill over its estimated useful life, with impairment testing where indicators arise, and where the useful life cannot be reliably estimated the standard imposes a cap. US GAAP's default model for goodwill is an impairment-only approach with no routine amortisation, although an accounting alternative is available to private companies that permits amortisation. That optionality is genuinely useful here, because a private UK company converting for Form 5471 purposes may be able to elect a US GAAP treatment that stays closer to its UK numbers, which reduces the size of the bridge and the ongoing cost of maintaining it.

The point to be careful about is that the choice has to be made deliberately, documented, and then applied consistently. Switching between an amortisation approach and an impairment-only approach across years, or applying one on Schedule C and a different logic in the earnings and profits computation, is exactly the kind of inconsistency that turns a routine information return into a reconciliation exercise. The same discipline applies to acquired customer lists, brands and software, where useful life assumptions under the two frameworks can differ even where the recognition principle does not.

How does lease accounting differ, and what changed under the Periodic Review 2024?

Historically this was one of the widest gaps. FRS 102 as previously drafted classified leases as operating or finance, and a lessee's operating leases stayed off the balance sheet with a straight-line rental charge. US GAAP under ASC 842 requires a lessee to recognise a right-of-use asset and a lease liability for leases with a term of more than twelve months, while retaining an operating and finance distinction for how the expense is presented. For a UK company with an office lease and a few vehicles, that difference alone could rewrite the Schedule F balance sheet.

The FRC's Periodic Review 2024 amendments narrow this. The headline changes include a new Section 20 that removes the operating and finance lease distinction for lessees and brings most leases on balance sheet as a right-of-use asset with a corresponding lease liability, with exemptions permitted for short-term leases and leases of low-value assets. The FRC has confirmed the principal effective date for the Periodic Review 2024 amendments as accounting periods beginning on or after 1 January 2026, with early application permitted, and the amendments were published on 27 March 2024. Supplier finance arrangement disclosures carry an earlier effective date of 1 January 2025.

For US filers this is good news structurally and awkward operationally. Going forward the UK and US balance sheets will look more alike on leases, so the recurring adjustment shrinks. But the transition year is a genuine problem: the UK accounts change basis mid-stream, the comparative period is restated under UK transition rules that do not match US GAAP transition rules, and the conversion schedule has to explain a change in the UK starting point as well as the usual UK to US bridge. Anyone preparing a Form 5471 for a UK company across that transition should expect the reconciliation for that year to be longer than usual and should not assume the prior-year bridge simply rolls forward.

Where do revenue recognition, holiday pay and other accruals move the profit figure?

Revenue is the second headline area of the Periodic Review 2024 amendments, with Section 23 substantially rewritten around a five-step model of the kind US preparers will recognise. Before those amendments bite, the practical divergences for owner-managed UK companies tend to sit in the timing of recognition on long-term or milestone contracts, the treatment of upfront fees, and the point at which a service arrangement is treated as satisfied. These rarely change annual profit dramatically for a stable business, but they can move a material amount of revenue across a year end in a company with lumpy contracts, and that year-end movement is precisely what feeds into a single year's earnings and profits.

Holiday pay is the accrual that catches UK companies out most often, and it runs in the opposite direction from what owners expect. FRS 102 requires an accrual for short-term employee benefits, including the undiscounted cost of unused paid annual leave expected to be settled within twelve months of the reporting date. Many UK companies carry a meaningful holiday pay accrual as a result. US GAAP has its own criteria for accruing compensated absences, and they are not identical, so the accrual may be measured differently or, in some fact patterns, not carried at all. Directors' bonuses accrued but unpaid at the year end deserve the same scrutiny, because the UK accounting accrual, the UK corporation tax deduction and the US GAAP position can each sit in a different period.

Why does deferred tax cause the most trouble on Schedule C line 21?

Because the two frameworks measure it from opposite ends of the accounts. FRS 102 measures deferred tax on a timing difference plus basis, which is fundamentally a profit and loss concept concerned with differences between when amounts enter the tax computation and when they enter accounting profit. ASC 740 uses the asset and liability method, comparing the carrying amount of each asset and liability on the balance sheet with its tax basis and recognising deferred tax on the resulting temporary differences. In many cases the two produce similar answers. In a UK company with revalued property, capitalised development costs, or significant differences between book depreciation and capital allowances, they do not.

This has a direct line-level consequence. Schedule C line 21 asks for income tax expense or benefit under ASC 740, including both current and deferred components. If the UK company reports under FRS 105 it recognises no deferred tax whatsoever, so line 21 has to be built from scratch. And the instructions add a further step that is easy to overlook: differences between the functional currency income tax expense or benefit reported on line 21 and the amount of taxes that actually reduce or increase US earnings and profits should be accounted for on line 2g of Schedule H. The deferred tax conversion therefore does not stop at Schedule C. It follows through into the earnings and profits computation.

What about investment property and financial instruments?

Investment property is a common holding in UK owner-managed structures and it produces one of the cleanest, largest adjustments. FRS 102 measures investment property at fair value with changes recognised in profit or loss, where fair value can be measured reliably without undue cost or effort. US GAAP for an operating entity generally carries real estate at historical cost less accumulated depreciation, with impairment testing. A UK company that has recognised several years of upward revaluation gains in its profit and loss account will see those gains reversed on conversion, and will pick up a depreciation charge that never existed in the UK accounts. Net assets on Schedule F fall, sometimes sharply.

Financial instruments are less dramatic but more fiddly. FRS 102 splits instruments into basic and other, with basic instruments generally at amortised cost and others at fair value through profit or loss. The recurring item in owner-managed companies is the director or shareholder loan on non-market terms, where the two frameworks can take different views on initial measurement and imputed interest. Derivatives deserve separate attention because Form 5471 addresses them directly: Schedule F lines 3 and 17 require derivative assets and liabilities to be reported in accordance with ASC 815, both short term and long term, and expressly prohibit netting positions. A UK company that shows a single net figure for an interest rate swap or a forward contract has to unpick it.

Why do these differences matter beyond presentation?

Because Schedule C is not a display case. It is the first number in a chain. Schedule H starts from net book income and applies the adjustments required by Regulations section 1.964-1(b) and (c) to arrive at current earnings and profits, and the instructions describe those adjustments as including both positive and negative adjustments to conform the foreign book income to US GAAP and to US tax accounting principles. Current earnings and profits then drive whether there is subpart F income, they feed the tested income figures on Schedule I-1 that flow through to Form 8992, and they determine what becomes previously taxed earnings and profits tracked on Schedules J and P. Previously taxed earnings and profits in turn affect the shareholder's basis in the stock, which surfaces years later on a sale or a liquidation.

Get the framework conversion wrong and every one of those figures is wrong by the same amount, in the same direction, in every subsequent year. That is the real cost. An error in a single year's Schedule C is an error; an error in the accounting framework is a permanent distortion of the previously taxed earnings and profits pool and of stock basis, and it is discovered at the worst possible moment, which is usually a transaction.

There is also a specific trap in the earnings and profits layer that interacts with the UK numbers. The instructions to Schedule H lines 2b and 2c state that depreciation, depletion and amortisation allowances must generally be based on the historical cost of the underlying asset, that depreciation must be figured according to section 167, and that if 20 percent or more of the foreign corporation's gross income is from US sources, depreciation must be figured on a straight-line basis. A UK company with a revalued property or a UK capital allowances mindset has to strip all of that out and rebuild on historical cost. This is one of the places where a UK accountant's instinct and the US requirement point in genuinely different directions.

Framework first or currency first, and does the order matter?

It matters, and the correct order is framework first, currency second. Convert the FRS 102 or FRS 105 figures to US GAAP in sterling, then translate the US GAAP sterling figures into dollars using US GAAP translation principles as the instructions require. Doing it the other way round produces figures that cannot be reconciled to anything.

The reason is arithmetic rather than doctrine. Translation applies different rates to different categories of item: broadly, average rates to income statement items and closing rates to balance sheet items, with equity carried at historical rates. If you translate the UK statutory figures into dollars first and then start making US GAAP adjustments, every adjustment has to be made in dollars at a rate you now have to select and justify individually, and the cumulative translation account no longer ties to anything. Reverse an item of capitalised development expenditure in dollars and you have to decide whether to reverse it at the rate on the date it was originally capitalised, the average rate for the year of capitalisation, or the current year's rate. Do the same reversal in sterling first and the question never arises, because the reversal simply changes the sterling balance that is then translated once, correctly, at the appropriate rate.

The instructions themselves quietly support this sequencing. Schedule H tells you that if the foreign corporation's books are maintained in functional currency in accordance with US GAAP, you enter on line 1 the functional currency GAAP income or loss from line 22 of Schedule C rather than starting with foreign book income, and show the GAAP-to-tax adjustments on lines 2a through 2i. The corollary, and the part that matters for a UK company, is that where the books are not maintained under US GAAP, the computation is expressly contemplated as starting from foreign book income with the conforming adjustments made on the way through. The regime is built for exactly the situation an FRS 102 company is in. It just expects you to show the work.

What conversion schedule would an examiner expect to see?

A single document that starts with the filed UK statutory accounts and ends with the numbers on the return, with every step visible. Not a memo describing the approach, and not a finished set of US GAAP statements with no visible provenance. The bridge is the deliverable. In the files we prepare it contains:

The filed FRS 102 or FRS 105 profit and loss account and balance sheet as the opening column, in sterling, tied to the Companies House filing or the signed accounts.
One row per accounting policy difference, with a plain-language description, the FRS 102 or FRS 105 treatment, the US GAAP treatment, and the sterling adjustment to profit and to net assets.
A materiality conclusion against each row, referencing the four factors in Regulations section 1.964-1(a)(2), including the rows concluded to be immaterial and therefore not adjusted.
A subtotal column showing US GAAP figures in sterling, which is the number that should agree to Schedule C's functional currency column.
The translation step, with the rates used, their source, and the date or period each rate relates to.
The US dollar column agreeing line for line to Schedule C and Schedule F as filed.
A separate continuation showing the US GAAP to earnings and profits adjustments carried to Schedule H lines 2a through 2i, so the chain from statutory accounts to earnings and profits is unbroken.

Keep the prior year's schedule and roll it forward. The cumulative effect of conversion adjustments on retained earnings is as important as the current year effect, and a bridge that only explains one year cannot support the balance sheet.

Does the IRS ever accept UK GAAP figures on Form 5471?

This is the question owners ask once they see the size of the exercise, and the answer is more interesting than a flat no. Page 1 of Form 5471 contains item F, a checkbox indicating that the form has been completed using alternative information as defined in Rev. Proc. 2019-40, and item G, where a code is entered describing what that information is. The codes are revealing. Code 01 is audited separate-entity statements prepared in accordance with US GAAP. Code 02 is audited statements under IFRS. Code 03 is audited statements prepared on the basis of the generally accepted accounting principles of the jurisdiction where the foreign corporation is organised, which the instructions call local-country GAAP, and which for a UK company means FRS 102 or FRS 105. Codes 04 to 06 are the unaudited equivalents, and codes 07 and 08 are separate-entity records used for tax reporting or for internal management controls.

So the IRS plainly knows that local-country GAAP exists and has built a taxonomy for it. The catch is who may use it. The instructions state that information described in a code qualifies as alternative information only if information described in any preceding code is not readily available, as defined in section 3.04 of Rev. Proc. 2019-40, so code 03 is only reachable if codes 01 and 02 are not readily available. More decisively, the safe harbours in sections 5 and 6 of the revenue procedure are framed for unrelated section 958(a) US shareholders and unrelated constructive US shareholders of foreign-controlled CFCs and certain specified foreign corporations. A US founder who owns and controls a UK company, and who can pick up the phone to the company's UK accountant, is not in that population and cannot credibly claim the underlying information is not readily available.

The practical value of knowing this is twofold. First, it settles the question: for the ordinary owner-managed case there is no shortcut, and the conversion has to be done. Second, it explains why generic advice found online sometimes says UK GAAP figures are acceptable. That advice is describing a narrow regime for minority shareholders in foreign-controlled companies, and applying it to a controlling owner is a straightforward misreading of the form.

What changes when the UK company is dormant or in its first year?

A genuinely dormant foreign corporation may be able to use the summary filing procedure in Rev. Proc. 92-70. Under it, only page 1 of Form 5471 is completed, the top margin is labelled to state that it is filed pursuant to Rev. Proc. 92-70 for a dormant foreign corporation, and specified filer and corporate information is included. Where that procedure is properly available there is no Schedule C and no Schedule F, and therefore no conversion at all. The discipline is to test the definition in the revenue procedure against the actual facts each year rather than assuming dormancy persists, because a single transaction can end it, and to remember that a company filing dormant accounts at Companies House is not automatically dormant for this purpose.

A first-year company presents the opposite problem: there is no prior conversion to roll forward and no comparative to sanity-check against. The compensations are that the trial balance is short, the fixed asset history is a single year, and there is no accumulated difference in retained earnings to unwind. The mistake to avoid is treating year one as too small to bother documenting. Year one is where the accounting policy elections are made, including any US GAAP private company alternatives, and those elections have to be applied consistently thereafter. A well-documented first-year bridge, even a one-page one, is the cheapest compliance asset a UK company will ever build.

A worked illustration: converting a UK consultancy from FRS 102

The following is an illustration only. Every figure below is assumed and illustrative, chosen to show the mechanics rather than to describe any client. Assume a UK trading company wholly owned by a US person, reporting under FRS 102 Section 1A, with a sterling functional currency and a 31 December year end. Its filed statutory accounts show a profit before tax of 900,000 pounds and net assets of 1,400,000 pounds. Assume an illustrative average rate for the year of 1.27 dollars to the pound and an illustrative closing rate of 1.29, both stated purely as assumptions for this example.

The conversion review identifies four differences. The company capitalised 260,000 pounds of development expenditure during the year and amortised 90,000 pounds of previously capitalised costs, so under US GAAP the 260,000 is expensed and the 90,000 amortisation is reversed, a net reduction in profit of 170,000 pounds and a reduction in intangible assets. The company carries an investment property revalued upward by 120,000 pounds through profit or loss, which is reversed under a historical cost model, with an illustrative depreciation charge of 15,000 pounds recognised instead, a net reduction in profit of 135,000 pounds. A holiday pay accrual of 40,000 pounds is remeasured to 25,000 pounds on the US GAAP criteria, increasing profit by 15,000 pounds. Deferred tax is rebuilt on a temporary difference basis, and the illustrative effect is a 30,000 pound increase in the deferred tax charge on Schedule C line 21.

The illustrative bridge therefore runs from 900,000 pounds of FRS 102 profit before tax, less 170,000, less 135,000, plus 15,000, to 610,000 pounds of US GAAP profit before tax in sterling, with the 30,000 pound deferred tax movement reflected on line 21 rather than in the pre-tax figure. Only at that point is the currency step taken, translating the sterling US GAAP income statement at the assumed average rate and the sterling US GAAP balance sheet at the assumed closing rate. Had the translation been done first, each of those four adjustments would have needed its own rate decision, and the resulting dollar figures would not have reconciled to either the UK accounts or the US GAAP position. The illustration also makes the substantive point: the US GAAP profit is roughly a third lower than the UK statutory profit, which changes the earnings and profits figure, the subpart F and tested income analysis and the previously taxed earnings and profits pool for every year that follows.

How we handle FRS 102 to US GAAP conversion in practice

The failure mode we see most often is not a wrong adjustment. It is an absent one, made invisible by a return that reports the UK statutory figures with a dollar sign in front of them. That return is internally consistent, superficially tidy, and wrong in a way that compounds annually. The second most common failure is the reverse: a US preparer with no UK accounting background rebuilding the company from first principles at great expense, when Regulations section 1.964-1(a) expressly permits starting from the books regularly maintained for accounting to shareholders and paragraph (a)(2) expressly limits the work to material items.

The right answer sits between them. Start from the UK trial balance rather than the filed accounts. Identify the accounting policies actually applied rather than assuming a standard set. Quantify each difference in sterling, test it against the four named materiality factors, adjust what is material and document what is not. Convert the framework, then translate the currency, in that order and never the other way round. Carry the result through to Schedule H and on into the earnings and profits and previously taxed earnings and profits records so the chain is unbroken. And keep the bridge, because the schedule that reconciles the Companies House filing to the Form 5471 is the document that makes the whole position defensible, in year one and in every year after it.