Do Dormant Companies Need to File a CT600?
If your limited company is dormant, you may be wondering whether you still need to file a company tax return — the form known as a CT600. The short answer is: once HMRC has been properly notified that your company is dormant, you generally do not need to keep filing CT600s. However, there are important steps you must take first, and obligations to Companies House continue regardless. This guide explains exactly what is required.
What Is a Dormant Company?
In HMRC's definition, a dormant company is one that is not trading and has no income — including no investment income, no interest received, and no other taxable activity. Even a single pound of bank interest can mean HMRC no longer considers your company dormant for Corporation Tax purposes.
It is important to note that HMRC and Companies House use different definitions of dormancy. Companies House considers a company dormant if it has had no "significant accounting transactions" during the period, whereas HMRC focuses on whether the company has any Corporation Tax liability.
This distinction matters in practice. A company may be dormant for Companies House purposes whilst still having obligations to HMRC — for example, if it has received a small amount of interest on a business bank account.
Do Dormant Companies Need to File a CT600?
Once you have formally notified HMRC that your company is dormant and HMRC accepts this, you are no longer required to file annual CT600 company tax returns. HMRC will stop sending you notices to deliver a tax return.
However, before you reach that point, there is one important obligation: if your company was previously required to file CT600s, you must submit a final CT600 covering the period up to the date of dormancy. You cannot simply stop filing without closing off the period during which the company was active.
Skipping this final return — or failing to notify HMRC at all — can result in penalties. See our guide on late CT600 filing and penalties for a full breakdown of what HMRC charges.
What If You Haven't Notified HMRC Yet?
If your company has been dormant for some time but you have never told HMRC, HMRC may still be expecting a company tax return. In this situation, it is not enough simply to stop filing.
You should:
- Identify the date on which your company became dormant (ceased trading, received no further income).
- File any outstanding CT600 returns up to and including that period.
- Notify HMRC in writing that the company is now dormant (more on how to do this below).
To understand whether your company was required to file in the first place, read our guide on who needs to file a company tax return.
How to Tell HMRC Your Company Is Dormant
You can notify HMRC that your company has become dormant by writing to them or by using your HMRC online account. The notification should state:
- The company name and registration number
- The date on which trading ceased
- Confirmation that the company has no income or taxable activity
If your company has never traded and was dormant from the moment of incorporation, you should still register for Corporation Tax and then immediately notify HMRC of the dormant status. HMRC typically accepts this without requiring any CT600 filing at all.
Companies House Obligations Still Apply
Even if your company is exempt from CT600 filings, it still has ongoing duties to Companies House. These do not go away simply because the company is dormant.
You must continue to:
| Obligation | Frequency |
|---|---|
| File annual accounts (dormant accounts) | Once per year |
| File a confirmation statement | Once per year |
| Notify Companies House of director or address changes | As they occur |
What If the Company Holds Assets or a Bank Account?
This is one of the most common sources of confusion. A company can be dormant for HMRC purposes even if it holds assets — such as property or equipment — provided those assets generate no income.
However, if the bank account earns interest, or if the company receives any form of income (rent, dividends from investments, or otherwise), it is no longer dormant for HMRC purposes. In that case, you would need to file a CT600 and pay any Corporation Tax due.
If you are unsure whether your company's circumstances meet the dormancy threshold, the safest step is to contact HMRC directly on 0300 200 3410 or speak to an accountant.
What If the Company Starts Trading Again?
If a dormant company resumes trading or begins to receive income, you must notify HMRC within three months of the start of the new accounting period in which the activity begins. Failure to do so can itself result in penalties.
Once you have notified HMRC, the company will need to:
- Register for Corporation Tax (if not already registered)
- Begin filing CT600 returns again for each accounting period
- Pay any Corporation Tax due within nine months and one day of the accounting period end
Common Questions
My company has been dormant for three years but I never told HMRC. Will I be penalised?
Potentially, yes — if HMRC issued you a notice to deliver a tax return and you did not file one. Late filing penalties start at £200 immediately upon the deadline being missed, rising to a further £200 at three months, then 10% of unpaid tax at six months and a further 10% at twelve months. Where a company has filed late for two consecutive years, the flat-rate penalties rise to £1,000 per occurrence. You should file any outstanding returns and notify HMRC of dormancy as soon as possible. HMRC may show leniency if you have a reasonable excuse and act promptly.
Does a dormant company need to pay Corporation Tax?
No. If a company has no taxable income and no Corporation Tax liability, there is nothing to pay. The obligation to file a CT600 arises from HMRC issuing a notice to deliver, not from having a tax bill. Once HMRC accepts your dormant status, both the filing obligation and any tax liability cease — unless the company's circumstances change.
Can a company be dormant if it has a registered office or uses a company secretary service?
Yes. Paying a registered office address provider or a company secretarial service does not count as trading activity for HMRC purposes. These are administrative costs, not income-generating transactions, and they do not affect dormant status. However, you should ensure no other income is flowing through the company.
Summary
Here is a quick overview of the key points for dormant companies and CT600 obligations:
- Once HMRC is notified of dormancy, you no longer need to file a CT600 each year.
- You must file a final CT600 covering the period up to dormancy if you were previously required to file.
- HMRC defines dormancy as no trading and no income — even small amounts of interest can break dormancy.
- HMRC and Companies House have different definitions — check both.
- Companies House obligations continue: annual accounts and a confirmation statement must still be filed.
- Assets are permitted, but any income from those assets ends your dormant status.
- If trading restarts, notify HMRC within three months and resume filing CT600s.
- Late filing penalties escalate quickly: £200 on the day, £200 at three months, then percentage-based charges at six and twelve months.
- HMRC helpline: 0300 200 3410 for Corporation Tax queries.