CT600 Nil Return: How to File When Your Company Has No Trading Activity

Got a limited company that hasn't traded? Maybe you set it up and never got started, or perhaps you've paused operations. Either way, you might still need to file a CT600 — even if there's nothing to report.

This guide explains exactly when a nil return is required, how to file one, and what happens if you don't.

What Is a CT600 Nil Return?

A CT600 nil return is simply a Company Tax Return where you declare that your company had no taxable income, no gains, and no Corporation Tax liability for the accounting period. Every figure on the return is zero (or close to it).

It's the same CT600 form that trading companies use — there's no special "nil return" version. You're just filling it in with zeros.

Does My Dormant Company Need to File a CT600?

This is the question most directors get wrong. The answer depends on whether HMRC considers your company "active" for Corporation Tax purposes.

You MUST file a CT600 nil return if:

HMRC has issued a "Notice to Deliver" a Company Tax Return (form CT603)
Your company is registered for Corporation Tax, even if it's not trading
Your company earned any bank interest (even a few pence)
Your company received any other income, however small

You may NOT need to file if:

Your company has been officially classified as dormant by HMRC
You've told HMRC the company is dormant and they've confirmed no return is needed

Key point: Being dormant at Companies House is NOT the same as being dormant for HMRC. You can be dormant at Companies House but still need to file a CT600 with HMRC. For a detailed breakdown of the differences, see our guide on dormant company corporation tax obligations. Always check your obligations with HMRC directly.

How to Tell HMRC Your Company Is Dormant

If your company has never traded or has stopped trading, you should notify HMRC:

For companies that have never traded: Write to HMRC or call the Corporation Tax helpline (0300 200 3410) to let them know the company has never been active. HMRC may then make it dormant on their records, meaning you won't receive a Notice to Deliver
For companies that have stopped trading: Write to HMRC within 3 months of ceasing to trade. Include your company name, UTR, company registration number, and the date trading stopped

If HMRC accepts the dormant notification, they'll stop issuing Notices to Deliver. But until that confirmation comes through, you should assume you still need to file.

Filing Deadlines for Nil Returns

The deadline is the same as for any CT600:

12 months after the end of your accounting period

For example, if your accounting period runs from 1 April 2025 to 31 March 2026, your CT600 nil return is due by 31 March 2027.

If you miss this deadline, HMRC will impose automatic penalties — even though you owe no tax. The penalties for late filing are:

How late	Penalty
1 day late	£100
3 months late	Another £100
6 months late	HMRC estimates your tax and charges 10% of that (minimum £100)
12 months late	Another 10% of estimated tax

Yes, HMRC will fine you for filing a zero return late. It doesn't matter that you owe nothing — the penalties are for the late filing, not late payment.

Step-by-Step: How to File a CT600 Nil Return

Option 1: Using HMRC's Online Service

Log in to your Government Gateway account
Navigate to Corporation Tax services
Select the accounting period and choose "File a return"
Complete the CT600 — enter zeros in the turnover, income, and tax fields
Attach nil accounts — you'll need to submit accounts in iXBRL format, even if they show zero activity. HMRC's service can generate basic nil accounts
Submit and save your confirmation receipt

Option 2: Using Commercial Software

Most CT600 software (including Taxpipe) supports nil returns. The advantage is that the software handles the iXBRL tagging for your accounts automatically, which is often the trickiest part of a nil return.

Option 3: Paper Filing

Paper CT600 filing is no longer accepted for most companies. You must file electronically.

What to Include in Your Nil Accounts

Even a nil return needs accounts attached. Your nil accounts should show:

Balance sheet with minimal or zero assets and liabilities (often just the £1 share capital)
Profit and loss / income statement showing zero turnover and zero expenses
Notes confirming the company was dormant or non-trading during the period

These accounts must be in iXBRL format — you can't just attach a PDF. This is where many directors get stuck, and it's one of the main reasons people use software even for nil returns.

Bank Interest: The Nil Return Trap

Here's a common gotcha: if your company has a business bank account with even £0.01 of interest earned, it's technically not a nil return. That interest is taxable income and must be declared.

In practice, the Corporation Tax on a few pence of interest is zero (it rounds down). But you still need to declare it. Don't just ignore it and enter zeros everywhere — HMRC can check bank records.

What If I Haven't Filed for Several Years?

If your non-trading company has missed multiple CT600 deadlines, you likely have penalty notices stacking up. Here's what to do:

File all outstanding returns immediately — even though they're late, filing stops further penalties accumulating
Appeal the penalties — if you have a reasonable excuse (e.g., you genuinely didn't know you needed to file), you can appeal using form SA370 online
Consider closing the company — if you have no plans to trade, striking off the company eliminates future filing obligations

Tip: HMRC is often sympathetic to appeals from dormant companies, especially first-time directors who weren't aware of the filing obligation. File first, then appeal.

Should I Just Close the Company Instead?

If your company has no assets, no liabilities, and you don't plan to use it, striking it off at Companies House (via form DS01, costing £33) is often the simplest option. Once the company is dissolved:

No more CT600 filing obligations
No more Companies House annual filings
No more Confirmation Statements

Just make sure all outstanding CT600s are filed before you apply for strike-off, or HMRC may object to the dissolution.

File Your Nil Return in Minutes with Taxpipe

Even a nil return requires iXBRL accounts and a properly completed CT600. Taxpipe handles all of that for you — just confirm your company had no activity, and we'll generate the return, tag the accounts, and file everything to HMRC electronically. No accountant needed, no iXBRL headaches. Get started for free.

CT600 Nil Return: How to File When Your Company Has No Trading Activity