How to file a dormant company tax return

In short: A company is dormant for Corporation Tax if it isn't trading and has no other income (such as investments). If HMRC has sent a "notice to deliver a Company Tax Return", you must still file a nil CT600 showing the company was dormant — even though no tax is due (GOV.UK). "Dormant for HMRC" and "dormant for Companies House" are two separate things.

A dormant company is one that is not carrying on any business activity and has no income for the period. Being dormant can reduce what you owe to nothing — but it does not automatically switch off your filing obligations. If you've been told to deliver a return, you can file a dormant (nil) return yourself in a few minutes.

What does 'dormant' mean for Corporation Tax?

A company is dormant for Corporation Tax when it has stopped trading and has no other income — for example, a company that has paused, or a new company that hasn't started trading yet (GOV.UK: dormant for Corporation Tax). With no trading and no income, there is no taxable profit, so no Corporation Tax is due for that period.

"No other income" is the part people miss: a company earning bank interest or other investment income is not dormant for Corporation Tax, even if it isn't trading.

Does a dormant company have to file a tax return?

It depends on whether HMRC has asked for one. If HMRC has sent a notice to deliver a Company Tax Return, you must file one — even when the company is dormant and owes nothing. As GOV.UK puts it, you'll still need to file a Company Tax Return online, and the return shows HMRC that the company was dormant for that period.

Once you've filed and HMRC accepts the company is dormant, HMRC may stop issuing notices for future years, so you won't have to file again until the company starts trading. Until that happens, ignoring a notice risks a late-filing penalty — £200 once it's late, and another £200 after three months (uprated from £100 for filing dates on or after 1 April 2026, GOV.UK penalties).

Dormant for HMRC vs dormant for Companies House

These are separate statuses with separate filings, and a company can be dormant for one but not the other. Confusing them is the most common dormant-company mistake.

Being dormant for Corporation Tax does not excuse you from Companies House: a dormant company must still file annual dormant accounts and a confirmation statement to stay on the register (GOV.UK: dormant for Companies House).

How to tell HMRC your company is dormant

1. Check you're actually dormant — no trading and no other income for the period.
2. Tell HMRC the company is dormant (you can do this through your business tax account or by contacting HMRC).
3. File any return HMRC has already requested — if a notice to deliver covers a period, submit a nil CT600 for it showing the company dormant.
4. Keep evidence of when trading stopped, in case HMRC asks.

If the company never traded at all, HMRC may not issue a notice — but if one arrives, you still answer it with a return.

What goes in a dormant company tax return?

A dormant Company Tax Return is a normal CT600 with nil figures — no trading profit, no income, no tax due — plus, where required, simple accounts showing the company was dormant. There's no Corporation Tax to pay, but the return is the formal record that closes off the period for HMRC.

Even though the numbers are zero, the return still needs your company UTR, your CRN, and Government Gateway details enrolled for Corporation Tax Online — the same references as any other CT600. Our guide to what a CT600 is covers those references in full.

Filing a dormant return with Taxley

Taxley has a dormant path built in: you confirm the company was dormant for the period, and it prepares a nil CT600 (and the accounts where needed) ready to file — without you working through boxes that don't apply. Because there's nothing to compute, a dormant nil return is the quickest and cheapest filing on the pricing page.

You're still responsible for confirming the company really was dormant. If it had any income or activity, it isn't dormant for Corporation Tax — file a normal return instead (for a rental company, see our property company guide). When you're ready, start your dormant return.

Frequently asked questions

Do I have to file a tax return for a dormant company?

Only if HMRC has sent a notice to deliver a Company Tax Return. If it has, you must file a nil CT600 showing the company was dormant, even though no tax is due. Once HMRC accepts the company is dormant, it may stop asking.

Is dormant for HMRC the same as dormant for Companies House?

No. They're separate. A company can be dormant for Corporation Tax yet still owe Companies House annual dormant accounts and a confirmation statement. Each is assessed under its own rules.

Does a dormant company pay Corporation Tax?

No. With no trading and no income, a dormant company has no taxable profit, so no Corporation Tax is due. You may still have to file a nil return to confirm that to HMRC.

What happens if I ignore a notice to deliver for a dormant company?

You can be charged a late-filing penalty — £200 once the return is late, and another £200 after three months — even though no tax is owed. File the nil return to avoid it.

Can a new company that hasn't started trading be dormant?

Yes. A company that has been set up but hasn't begun trading and has no income can be dormant for Corporation Tax. If HMRC issues a notice before you start trading, file a nil return for that period.

Taxley prepares the CT600 and, where needed, dormant accounts as iXBRL from the details you enter, ready to file. This guide is general information, not tax advice — you're responsible for confirming the company was dormant and for the accuracy of the return.