Late CT600 and Companies House Penalties for US Owners

For an American-owned UK trading company, late CT600 and Companies House penalties run on two separate clocks. Companies House charges £150 to £1,500 for late accounts, doubled if they are late two years running. HMRC charges £200 and then a further £200 on a late CT600, followed by 10% or 20% of unpaid tax, plus late payment interest.

This guide is written for the founder who kept the business trading but let the company's filings slide while personal US and UK returns took priority. It sets out every penalty figure as it stands in September 2026, the order in which to repair the damage, how appeals actually work at each regulator, the strike-off risk, and the part generalist guides leave out: what overdue UK statutory accounts do to your own US returns for the same years. At Jungle Tax we prepare both sides of that catch-up, so the figures filed in London and the figures filed with the IRS finally agree.

Two regulators, two clocks: why the penalties stack

Companies House and HMRC are separate bodies enforcing separate laws. Companies House administers company law: every UK company must deliver statutory accounts and an annual confirmation statement to the public register. HMRC administers tax law: once it has issued a notice to deliver, the company must file a Company Tax Return (form CT600) with its accounts and tax computations attached. One set of accounts feeds both, but each regulator has its own deadline, its own penalty scale and its own appeal test, and neither waives its penalty because the other has been satisfied.

Since 1 April 2026 the two filings are also physically separate for every company. HMRC's free joint service for filing accounts and tax returns closed on 31 March 2026, so the CT600, the computations and the tagged accounts must now reach HMRC through commercial software, while the accounts go to Companies House through its own channel. Founders who used the old combined service in earlier years often assume one submission still does both. It no longer does, and a catch-up that files only half the pair leaves the other penalty clock running.

Obligation	Regulator	Statutory rule	Deadline for a year ended 30 June 2025
Statutory accounts	Companies House	9 months after the financial year ends (first accounts: 21 months after incorporation)	31 March 2026
Corporation tax payment	HMRC	9 months and 1 day after the accounting period ends (large companies pay by instalments)	1 April 2026
CT600, accounts and computations	HMRC	12 months after the accounting period ends	30 June 2026
Confirmation statement	Companies House	Within 14 days of the end of each 12-month review period	Set by incorporation date or last statement

What are the Companies House late filing penalties?

Companies House penalties are automatic, fixed by statute and charged to the company. The amount turns only on how late the accounts arrive. The deadline does not move if it falls on a weekend or bank holiday, and delivery means accounts received and accepted in the correct form, not merely posted. The current scale, published on gov.uk, is:

Time after the filing deadline	Private company	Public company
Up to 1 month	£150	£750
1 to 3 months	£375	£1,500
3 to 6 months	£750	£3,000
More than 6 months	£1,500	£7,500

The penalty is doubled when the accounts for the previous financial year were also late. A founder two years behind therefore typically faces £1,500 on the first set and £3,000 on the second, before HMRC has charged anything. Unpaid penalties go to debt collection and, ultimately, county court proceedings against the company.

The penalty is the company's liability, but the filing duty is personal to each director. Under Companies House's own late filing guidance, failing to deliver accounts or confirmation statements is a criminal offence, and directors can be personally fined. Prosecutions of directors for non-filing have risen markedly since the Economic Crime and Corporate Transparency Act 2023 gave Companies House more staff and powers, including civil financial penalties of up to £10,000 for a wide range of company law failures since May 2024. Being resident in the United States is no defence, and repeated convictions can lead to disqualification.

An extension is possible only in narrow cases. The application must be made before the deadline, the reason must be outside the company's control (sudden illness, records destroyed), and the law caps the total filing period at 12 months. Once the deadline has passed, the extension route is closed and the only questions are how late the accounts will be and whether the penalty can be appealed.

The confirmation statement: no sliding-scale fine, but the fastest route to strike-off

The confirmation statement is due within 14 days of the end of each 12-month review period and costs £50 online. Unlike the accounts, there is no automatic late filing scale. The gov.uk guidance is nonetheless clear that a company can be fined up to £5,000, may receive a financial penalty, and may be struck off if the statement is not filed. In practice, a missing confirmation statement alongside missing accounts is exactly the pattern that leads the registrar to conclude the company is no longer carrying on business.

The statement has also become harder to file at the last minute. Since 18 November 2025 every director must verify their identity, and each confirmation statement must carry each director's Companies House personal code. Existing directors supply the code with the company's next confirmation statement. The statement must also confirm that the company's intended future activities are lawful and give a registered email address. For an American director living in the US, verification can take time, so start it on day one of the catch-up rather than on the day the statement is due.

What are the HMRC penalties for a late CT600 in 2026?

HMRC's fixed penalties for late company tax returns doubled for returns whose filing date falls on or after 1 April 2026. It is the first increase since 1998, confirmed in HMRC's policy paper on the increases. The scale that applies depends on each return's statutory filing date, not the date you finally file it, so a multi-year catch-up often mixes the old and new scales.

CT600 failure	Filing date before 1 April 2026	Filing date on or after 1 April 2026
Return delivered late	£100	£200
Return more than 3 months late (total)	£200	£400
Third successive late return	£500	£1,000
Third successive return, more than 3 months late	£1,000	£2,000

The tax-geared penalty is usually the larger number

Headline articles focus on the £200, but for a profitable trading company the tax-geared penalty matters far more. Under HMRC's Company Taxation Manual at CTM94060, a company that has not delivered its return by 18 months after the end of the accounting period (or the filing date, if later) incurs a further penalty based on the tax still unpaid at that point. It is 10% of that unpaid tax if the return is delivered within two years of the period end, and 20% if it arrives later. On HMRC's public penalty page the same rule appears in simpler form: 10% at six months late, and another 10% at twelve months.

Two practical points follow. First, because the penalty is measured on tax unpaid at the trigger date, paying a realistic estimate of the corporation tax before that date can reduce the tax-geared penalty to nil even if the return itself is still late. Second, a loss-making or nil-tax company still owes the fixed penalties, because the obligation to file does not depend on tax being due.

Determinations and the 2026 penalty notice pause

Once a return is six months overdue, HMRC can issue a determination: its own estimate of the tax, which it can collect as if the company had self-assessed it. A determination cannot be appealed. It is displaced only by filing the actual return within the statutory time limits, and HMRC then recalculates interest and penalties. Founders sometimes treat a determination as the end of the matter. It is not; it is usually an overestimate with enforcement attached.

While HMRC updated its systems for the new penalty amounts, automatic corporation tax penalty notices were temporarily paused in spring 2026 and resumed over the summer. Companies that filed late during the pause may receive their notices later than expected. A missing letter is not a missing penalty.

Late payment interest

Interest is separate from penalties and runs from the day after the normal payment date until the tax is paid. Since 6 April 2025 HMRC's late payment rate has been base rate plus 4 percentage points, which gives 7.75% from 9 January 2026 at the time of writing. Because interest is compensation rather than a penalty, no reasonable excuse will remove it; the only way to stop it is to pay. Companies large enough to pay by quarterly instalments are subject to different interest rules.

Worked example: two years behind in September 2026

Consider an American founder living in London whose UK consulting company has a 30 June year end. Accounts and CT600s for the years ended 30 June 2024 and 30 June 2025 are unfiled, the previous year was filed on time, and £40,000 of corporation tax is outstanding for each year. It is 10 September 2026.

• Year ended 30 June 2024. The accounts were due on 31 March 2025 and are already more than six months late: £1,500. The CT600 filing date was 30 June 2025, so the old scale applies: £100 plus £100. The 18-month point was 31 December 2025, when the full £40,000 was unpaid, and the return can no longer be delivered within two years of the period end, so the tax-geared penalty is 20%: £8,000.
• Year ended 30 June 2025. The accounts were due on 31 March 2026. Delivered by 30 September 2026 they fall in the three-to-six-month band (£750, doubled to £1,500); delivered later they cost £3,000. The CT600 filing date was 30 June 2026, so the new scale applies: £200 already, another £200 if the return is still outstanding after 30 September 2026. The 18-month point is 31 December 2026: pay the tax or file before then and there is no tax-geared penalty; miss it and 10% (£4,000) follows.

Penalty	Everything filed and paid by 30 September 2026	Left until 2027
Companies House, 2024 accounts	£1,500	£1,500
Companies House, 2025 accounts (doubled)	£1,500	£3,000
HMRC fixed, 2024 CT600	£200	£200
HMRC tax-geared, 2024 CT600	£8,000	£8,000
HMRC fixed, 2025 CT600	£200	£400
HMRC tax-geared, 2025 CT600	£0	£4,000
Total penalties (before interest)	£11,400	£17,100

Three weeks of focused work changes the outcome by £5,700 before interest, and the largest single item is a tax-geared penalty the fixed-penalty headlines never mention. The same founder's 2024 and 2025 US returns each straddle two UK accounting periods, so neither can be completed accurately until both sets of accounts exist, a point we return to below.

In what order should you fix late CT600 and Companies House filings?

The right sequence protects the company's existence first, then stops the most expensive clocks, and only then turns to appeals and personal returns.

1. Check the public register today. If the company's status reads "Active – proposal to strike off", this becomes the priority. Contact Companies House, show that overdue documents are being prepared, and lodge any objection within the two-month Gazette window.
2. Verify every director's identity and file the confirmation statement. It is fast and inexpensive, and it removes one of the two signals that drive compulsory strike-off.
3. Pay a realistic estimate of the corporation tax. Payment stops interest immediately, and tax paid before each 18-month trigger falls outside the tax-geared penalty.
4. Prepare accounts oldest-first, but file against the next threshold. Each year's opening balances depend on the last, so the work runs chronologically. Plot every Companies House band, every three-month HMRC step and every 18-month trigger on one calendar, and file whichever set is closest to a step change first.
5. File each CT600 with its computations and tagged accounts through commercial software. This displaces any HMRC determination and fixes the true tax, penalty and interest position.
6. Reconcile the owner's position inside the company. Dividends, the director's loan account and payroll figures should be settled against the final accounts before any personal return is prepared.
7. Appeal once the returns are filed. HMRC will not consider a late filing appeal until the return is in.
8. Then prepare the personal UK and US returns from final, filed company figures, not management accounts.

Can you appeal? Reasonable excuse versus exceptional circumstances

The two regulators apply very different tests, and advice that works for one routinely fails at the other.

HMRC accepts appeals against CT600 penalties where the company had a reasonable excuse, but only after the return has been filed, and usually within 30 days of the penalty notice. HMRC's published list includes bereavement shortly before the deadline, an unexpected hospital stay, serious illness, software or HMRC system failure and, notably, relying on someone else who then failed to file, or being unaware of or misunderstanding the obligation. Each is judged on the facts, and the excuse only helps if the failure was remedied without unreasonable delay once it ended. "I was dealing with my personal US and UK returns" is a priority choice, not an excuse. A first-year American founder who genuinely did not understand the notice-to-deliver regime has a far stronger case than a director with years of UK filings behind them. If HMRC refuses, you can ask for a review or go to the tax tribunal, normally within 30 days.

Companies House has far less room. Its guidance describes very limited discretion and requires circumstances that were genuinely exceptional and outside the company's control. It lists reasons that normally fail: reliance on an accountant, the accountant's illness, directors being overseas, the company being dormant and the penalty being unaffordable. A rejected appeal can go to a senior casework review and then to independent adjudicators, who cannot compel the registrar to reverse a decision.

Appeal feature	HMRC (late CT600)	Companies House (late accounts)
Legal test	Reasonable excuse, remedied without unreasonable delay	Exceptional circumstances outside the company's control
File first?	Yes, before HMRC will consider the appeal	The penalty band is fixed by the delivery date
Usual time limit	30 days from the penalty notice	As stated on the penalty notice
Reliance on an adviser	Listed as potentially reasonable, judged on the facts	Expressly rejected
Director living abroad	Rarely sufficient alone	Expressly rejected
Escalation	HMRC review, then the tax tribunal	Senior casework review, then independent adjudicators

What happens if Companies House strikes the company off?

Where the registrar has reasonable cause to believe a company is not carrying on business, and unanswered letters about overdue accounts and confirmation statements are the classic evidence, it can begin compulsory strike-off under section 1000 of the Companies Act 2006. After warning letters, a first notice is published in the Gazette and the register shows a proposal to strike off. Unless cause is shown within two months, the company is struck off and dissolved.

For a trading company, dissolution is severe. Everything the company owned, including its bank balance, receivables and intellectual property, vests in the Crown as ownerless property, and the bank account is frozen. Contracts and invoices issued after dissolution are issued by a company that no longer exists. A former director or member can apply for administrative restoration within six years if the company was carrying on business when it was struck off, the Crown's representative consents, all overdue accounts and confirmation statements are delivered, and outstanding penalties are paid. Otherwise restoration requires a court application. Either way, every late filing must be cured as the price of return.

There is a US dimension here that UK-only guides miss. Under UK company law a restored company is generally treated as having continued in existence as if it had never been dissolved, but the US treatment of a dissolve-and-restore sequence, and of any final dissolution, needs separate analysis on the owner's return. A dissolution can look like a liquidation of a foreign corporation for US purposes, with its own reporting in the year it happens. Preventing strike-off is far cheaper than explaining it to two tax authorities.

How do overdue UK accounts affect the owner's US returns?

For an American who owns 10% or more of a UK company, the company's statutory accounts are not just a UK document; they are the raw material for the owner's own US return. Missing UK accounts do not pause US deadlines. They simply leave the US return without its source figures.

• Information reporting. The owner typically has to file Form 5471 with their Form 1040, reporting the company's income statement, balance sheet, earnings and profits, UK taxes and related-party balances. The penalty for a missing or incomplete form starts at $10,000 per form per year, applies whether or not any US tax is due, and can keep the assessment period on the return open. Without finished UK accounts, those schedules cannot be completed properly.
• Income inclusions and foreign tax credits. A UK company controlled by US shareholders is a controlled foreign corporation, and its owner may have to include a share of the company's income on their US return whether or not a dividend was paid. The amount is computed from the company's accounts, and the relief for UK corporation tax depends on the tax actually assessed on the CT600. Until the CT600 is filed and the UK tax is fixed, the US computation is provisional at best.
• Mismatched years. Where one American owns a majority of the company, US rules generally require the company's US tax year to follow the owner's calendar year, and the one-month deferral election was repealed for years beginning after 30 November 2025. A company with a 30 June year end therefore feeds each US year from two sets of UK accounts, and both must exist before that US year can be finished.
• FBAR on the company's bank accounts. A director with signature authority over the company's UK accounts, or an owner of more than half of the company, generally has to report those accounts on the FBAR, even though the money belongs to the company. Our FBAR penalty calculator shows how quickly unreported years accumulate.

Americans living abroad receive an automatic extension of the Form 1040 deadline to 15 June and can extend further to 15 October, which is often the cleaner route when UK accounts are weeks away. Filing the US return on management accounts and amending later is sometimes unavoidable, but it doubles the work. Where US years have already been missed, the Streamlined Foreign Offshore Procedures allow eligible non-willful taxpayers who meet the non-residency test to file three years of returns and six years of FBARs without failure-to-file, accuracy-related, information return or FBAR penalties. Those three years of returns need the UK accounts for the same years, which makes the UK company catch-up the critical path for any IRS streamlined filing. Our US tax services team prepares the US side from the same working papers used for the CT600.

What are the director's personal Self Assessment knock-ons?

Being a director no longer, by itself, obliges someone to file a Self Assessment return, but most owner-directors who draw meaningful dividends or other untaxed income still must. From the 2025-26 tax year, directors completing a return must confirm their directorship, and directors of close companies must report the company's name and registration number, the dividends they received from it and their percentage shareholding. A director's return that reports dividends from a company with no accounts on the register is an easy match for HMRC's systems.

Late accounts also make it hard to prove what the director actually received. Dividends declared while the filings lapsed must be supported by distributable reserves shown in the company's accounts. If the late accounts reveal a shortfall, payments treated as dividends may have to be treated differently, which changes the director's UK return and the owner's US return for the same year. An overdrawn director's loan account not repaid within nine months of the year end triggers a temporary corporation tax charge under section 455, reported on the CT600, so an unfiled CT600 often hides an unreported section 455 charge. Loans above £10,000 can also create a taxable benefit reportable on form P11D.

The director's own penalties then run alongside the company's: £100 for a late Self Assessment return, £10 a day after three months up to £900, and the greater of 5% of the tax due or £300 at six and again at twelve months, plus 5% late payment penalties at 30 days, six months and twelve months. For an American director resident in the UK, that UK return in turn feeds the US foreign tax credit, so each link in the chain waits on the one before it.

How the US and UK systems compare for a late company

Question	UK: HMRC and Companies House	US: IRS (owner's personal return)
Who is penalised	The company, with directors exposed to prosecution for non-filing	The US owner personally
What triggers it	Late accounts, late CT600, late confirmation statement	Missing or incomplete Form 5471, FBAR and income inclusions
Penalty with no tax due?	Yes: fixed penalties apply regardless	Yes: information return penalties apply regardless
Scale	£150 to £3,000 per set of accounts; £200 to £2,000 fixed per CT600, plus 10% or 20% of unpaid tax	From $10,000 per Form 5471 per year; FBAR penalties separate
Relief route	Reasonable excuse (HMRC); exceptional circumstances (Companies House)	Reasonable cause; streamlined procedures for eligible non-willful filers
Long-tail risk	Determinations, strike-off and six-year restoration window	Assessment period can stay open while an information return is missing

What changed in 2026: a checklist for returning founders

• CT600 fixed penalties doubled for returns with a filing date on or after 1 April 2026.
• HMRC's joint accounts and tax filing service closed on 31 March 2026; CT600s now require commercial software.
• Automatic CT penalty notices were paused and then resumed, so late notices may still be in the post.
• Every director must be identity-verified, with a personal code on the next confirmation statement.
• Late payment interest remains at base rate plus 4 percentage points.
• Close company directors face new disclosure boxes on their 2025-26 Self Assessment returns.
• Companies House has announced a move to software-only accounts filing and changes to small company filing options, so older paper and web habits will not survive.

For more on the personal side of a lapse, our guides library covers late Self Assessment, FBAR and streamlined filing in depth, and our US-UK tax accountants work across both systems as a single engagement.

Bring the company and your personal returns back into line

A lapsed UK company rarely stays a UK problem for an American owner. The same missing accounts that trigger Companies House and HMRC penalties also leave your US returns, FBARs and Self Assessment returns without their source figures, and every month of delay moves another penalty threshold closer. We prepare the overdue statutory accounts, CT600s and appeals, then carry the same figures into your US and UK personal returns so the whole position is corrected once, in the right order. For a discreet review of where your company and your own filings stand, contact our cross-border team to arrange a confidential consultation.