How to File a Nil CT600 Return for a Dormant Company
Your company hasn't traded. No income, no expenses, no activity. But HMRC still expects a Corporation Tax return. If you don't file, you'll face penalties starting at £100 — even though you owe nothing.
This guide shows you exactly how to file a nil CT600 return for your dormant company.
What Is a Dormant Company?
A company is dormant for Corporation Tax purposes if it has:
- No trading income
- No investment income
- No chargeable gains
- Made no accounting transactions (other than filing fees)
Important distinction: A company can be "dormant" at Companies House but "active" for HMRC purposes, and vice versa. For CT600 purposes, even minimal activity (like earning bank interest) means you're not dormant.
Do I Still Need to File a CT600?
Yes. Until HMRC confirms your company is dormant, you must file a CT600 return for every accounting period. Filing a nil return takes very little time and avoids penalties.
How to Tell HMRC You're Dormant
You can ask HMRC to stop issuing CT600 notices by:
- Writing to HMRC Corporation Tax Services
- Calling the Corporation Tax helpline (0300 200 3410)
- Filing a nil return and ticking the "dormant" box
Once HMRC confirms dormancy, they'll stop sending notices. But if your company starts trading again, you must tell HMRC within 3 months.
What Goes in a Nil CT600?
A nil return is straightforward — most boxes are zero or left blank:
Company Details (Always Required)
- Box 1 — Company name
- Box 2 — Company registration number
- Box 3 — UTR (Unique Taxpayer Reference)
- Box 30 — Accounting period start date
- Box 35 — Accounting period end date
Financial Boxes (All Zero)
- Box 155 — Total turnover: £0
- Box 165 — Net trading profit: £0
- Box 235 — Profits before deductions: £0
- Box 300 — Profits before charges: £0
- Box 315 — Profits chargeable to CT: £0
- Box 430 — Corporation tax chargeable: £0
- Box 440 — Net CT chargeable: £0
- Box 525 — Tax payable: £0
Declaration
- Box 975 — Name of person signing (usually the director)
- Box 985 — Status: Director
Attachments
Even a nil return needs:
- iXBRL micro-entity accounts showing zero turnover and zero profit
- A basic tax computation (showing nil tax)
Penalties for Not Filing
| How Late | Penalty |
|---|---|
| 1 day late | £100 |
| 3 months late | Another £100 |
| 6 months late | HMRC estimates your tax + 10% penalty |
| 12 months late | HMRC estimates your tax + additional 10% |
Even though your tax bill is £0, HMRC will still charge the £100 fixed penalties. After 6 months, they may estimate your tax liability at a non-zero amount, creating a much larger problem.
Full guide to CT600 penalties →
Filing Options for Nil Returns
Option 1: Taxpipe (£59)
Taxpipe handles nil returns just like any other CT600. Enter your company details, confirm zero income and expenses, and we generate:
- Nil CT600 return
- iXBRL micro-entity accounts (with zero values)
- Tax computation
- Direct submission to HMRC
Option 2: HMRC Free Tool (Ending March 2026)
HMRC's free CT600 filing service can handle nil returns, but it's being retired in March 2026.
Option 3: Accountant (£150-£400)
Even for a nil return, most accountants charge their minimum fee. This is expensive for zero-activity companies.
Should You Close the Company Instead?
If your company has been dormant for more than a year with no plans to trade, consider:
Striking Off (Cheapest Option)
- Apply to Companies House for voluntary strike-off (form DS01)
- Costs nothing (just the form)
- Company is dissolved after 3 months if no objections
- Must be up to date with all HMRC filings first
Members' Voluntary Liquidation (For Companies with Assets)
- More formal process with a licensed insolvency practitioner
- Required if the company has significant assets to distribute
- More expensive (typically £1,500-£3,000)
Guide to closing your limited company →
Common Questions
Can I file a nil return myself?
Yes. A nil CT600 is the simplest possible return. With software like Taxpipe, it takes about 10 minutes.
What if I earned bank interest?
If your company earned even £1 of bank interest, it's not technically dormant. You'll need to declare the interest income on your CT600 (but the tax due will be minimal).
My company was struck off — do I still need to file?
If the company was struck off mid-period, you need to file a CT600 covering the period up to the date of dissolution. After that, no more returns are needed.
What about Companies House accounts?
Dormant companies still need to file accounts at Companies House — but these can be simple dormant accounts (form AA02) filed free of charge.
File Your Nil Return Now
Don't wait for penalties to stack up. File your nil CT600 with Taxpipe for £59 — or less time than it takes to argue with HMRC about late filing penalties.