Do I Need to File a CT600 If My Company Made No Profit?

Yes. If your limited company is registered for corporation tax with HMRC, you almost certainly need to file a CT600 — even if you made no profit, had no income, or did absolutely nothing all year.

This catches out thousands of directors every year. They assume "no profit = no tax = no filing." Then a penalty notice arrives in the post. £100 gone, just like that — for a return that would have shown £0 tax owed.

Let's clear this up once and for all. We'll cover every scenario: loss-making companies, dormant companies, newly formed companies that haven't traded yet, and companies about to close. Plus, we'll show you exactly how to file a nil CT600 in minutes.

The Short Answer: Almost Every Company Must File

HMRC requires a CT600 from every company that is active for corporation tax purposes. This means:

Your company has been incorporated at Companies House, AND
HMRC has set up a corporation tax record for your company (they do this automatically when you incorporate)

The obligation exists regardless of whether you:

Made a profit
Made a loss
Had any income at all
Actually traded
Are planning to close the company

The only exception is if HMRC has formally agreed that your company is dormant for corporation tax purposes and has made it dormant in their systems. We'll explain that exception properly below — because it's narrower than most people think.

Scenario 1: Your Company Traded But Made a Loss

If your company was actively trading during the accounting period but expenses exceeded income (i.e., you made a loss), you absolutely must file a CT600.

Here's why this matters beyond just avoiding penalties:

Filing Locks In Your Loss for Future Use

Corporation tax losses can be incredibly valuable. If you make a £20,000 loss this year and a £30,000 profit next year, you can offset the loss against the profit — reducing your taxable profit to £10,000 and saving up to £5,000 in corporation tax.

But here's the catch: HMRC needs to know about the loss. You declare it on your CT600. If you don't file, the loss isn't formally recorded, and you could lose the ability to use it.

Learn how to use losses: Corporation tax losses: how to carry forward and carry back

What Goes on Your CT600 for a Loss-Making Year?

You still fill in the standard boxes — company information, turnover, expenses, and the resulting loss. The tax calculation will show £0 tax owed.

Key boxes you'll complete:

Box 145 (Turnover): Your total sales/income
Box 155 (Trading profits): £0 (since you made a loss)
Box 780 (Losses): The amount of your trading loss
The tax computation section will show no tax payable

You'll also need to submit iXBRL-tagged accounts with your return, even if those accounts show a loss.

Need help with boxes? See our CT600 box-by-box guide.

How Taxpipe Handles Loss-Making Companies

Taxpipe is designed for this exact situation. You enter your income and expenses, and we handle everything else — including calculating and declaring the loss, generating the iXBRL accounts, and filing with HMRC. £59, about 15 minutes, done.

You don't need to understand how Box 780 works or what a "Type I" loss claim looks like. We sort that out for you.

File your nil/loss return now →

Scenario 2: Your Company Exists But Hasn't Traded

Maybe you formed a company but never got around to trading. It's just sat there on Companies House — no bank account, no transactions, no activity.

You might think: "Surely HMRC doesn't want a return from a company that did literally nothing?"

They do. If HMRC has your company on their corporation tax register (and they will, since Companies House notifies them of every new incorporation), they expect a CT600 for every accounting period.

The "Dormant for Corporation Tax" Exception

There IS an exception, but it requires you to actively contact HMRC and tell them your company is dormant. Here's how it works:

You write to HMRC (or call them) and tell them your company has been dormant — meaning it has had no business transactions whatsoever during the accounting period
HMRC reviews and, if they agree, marks your company as dormant on their system
Once dormant, HMRC won't issue notices to file and won't expect CT600 returns — until you tell them the company has become active again

But — and this is the crucial bit — dormant for corporation tax purposes means zero transactions. Not "very few." Not "just a little bank interest." Zero. Even a tiny amount of bank interest technically makes your company active for CT600 purposes.

Detailed dormant filing guide: Dormant company CT600 filing: do you still need to file?

What If You Haven't Told HMRC You're Dormant?

If you never contacted HMRC to tell them your company is dormant, they're still expecting returns. That means:

Penalties are accumulating for every unfiled period
HMRC may have already estimated your tax liability
You need to file all outstanding returns to clear the record

The fastest way to sort this out is to file the overdue returns (showing nil activity) and then ask HMRC to make the company dormant going forward.

Already accrued penalties? Read what happens if you miss the CT600 deadline to understand the penalty structure and how to appeal.

Scenario 3: Your Company Has Only Earned Bank Interest

A common situation: your company has money in a bank account earning interest, but isn't actively trading. Is that enough to trigger a CT600 requirement?

Yes. Bank interest is taxable income. Your company needs to:

File a CT600 reporting the interest income
Pay corporation tax on that interest (at 19% or 25% depending on your total profits)

Even if the interest is small — say, £50 — the filing obligation exists. The tax might only be £9.50, but the penalty for not filing is £100.

More on this: Corporation tax on bank interest: how it works

Scenario 4: Your Company Is About to Be Closed Down

If you're planning to close your company, you still need to file a CT600 for the final accounting period — from the start of the last period up to the date of cessation.

Many directors assume they can just dissolve the company and everything goes away. It doesn't. HMRC will pursue outstanding returns even after a company has been struck off, and they can request restoration of the company at Companies House specifically to issue penalties.

Closing your company? Read Closing a limited company: your final CT600 and what to do

Scenario 5: You Just Incorporated and Haven't Done Anything Yet

When you incorporate a limited company, HMRC automatically sets up a corporation tax record. They'll write to your registered office with your UTR (Unique Taxpayer Reference) and your first accounting period dates.

Your first CT600 is due 12 months after the end of your first accounting period. If you incorporated on 1 June 2025, your first accounting period likely runs to 31 May 2026, and your first CT600 is due by 31 May 2027.

Even if you haven't started trading by then, you need to file — unless you've contacted HMRC to go dormant.

New company? Our first company tax return guide walks you through everything.

What Is a "Nil Return" and How Do I File One?

A nil return (sometimes called a nil CT600 or zero return) is simply a CT600 that reports no taxable profit and no tax due. It's a real CT600 — you can't just send HMRC a letter saying "nothing to report." You need to submit the actual form electronically, with iXBRL-tagged accounts.

A nil return includes:

Your company details (name, UTR, accounting period)
A profit and loss account showing no (or minimal) activity
A balance sheet
The CT600 form itself with zeros in the tax calculation boxes
iXBRL-tagged accounts (a legal requirement for all CT600 submissions)

The iXBRL Requirement

This is what trips up most directors trying to file a nil return themselves. Even if there's nothing to report, HMRC requires your accounts in iXBRL format (Inline eXtensible Business Reporting Language). You can't just upload a PDF or type numbers into a box.

iXBRL conversion requires specialist software. You can't do it in Excel, Word, or standard accounting packages that don't have built-in tagging.

More on iXBRL: iXBRL accounts: what are they and why you need them for your CT600

Filing a Nil Return With Taxpipe

This is where Taxpipe comes in. We handle the iXBRL conversion automatically. You don't need to understand what iXBRL is or how it works. Our process:

Sign up — takes 2 minutes
Enter your company details — we pull information from Companies House automatically
Answer a few questions — plain English, no jargon
We generate your iXBRL accounts and CT600 — automatically
We file with HMRC — electronically, instantly

Total time: about 10-15 minutes. Cost: £59. Compare that to the £100-£200 in penalties for not filing, and it's a no-brainer.

File your nil return now →

What About Companies House Dormant Accounts?

There's an important distinction between:

Dormant at Companies House — you file simplified "dormant accounts" instead of full annual accounts
Dormant at HMRC — you don't need to file CT600 returns

These are separate things with separate criteria. A company can be dormant at Companies House but still need to file CT600s with HMRC, or vice versa.

Companies House considers you dormant if you've had no significant accounting transactions during the period (other than shares issued on formation and filing fees paid to Companies House).

HMRC considers you dormant only if you've had no business transactions at all — and only after you've told them and they've agreed.

Don't assume that filing dormant accounts at Companies House means you're covered with HMRC. Check both.

The Cost of Not Filing vs. the Cost of Filing

Let's do the maths:

Not Filing (First Year Late)

£100 penalty (1 day late)
£100 penalty (3 months late)
Potential HMRC determination of your tax (they guess, usually high)
Stress of dealing with penalty notices
Risk of further penalties if you continue not filing
Total: £200+ in penalties, plus ongoing compliance issues

Filing With Taxpipe

£59 flat fee
15 minutes of your time
Proper iXBRL accounts filed with HMRC
Loss recorded (if applicable) for future tax relief
Clean compliance record
Total: £59

The maths doesn't lie. Filing a nil return costs less than a single late filing penalty.

See Taxpipe pricing →

What If I'm Already Late? Can I Still File?

Absolutely. File now and limit the damage:

Under 3 months late: You'll face the £100 penalty but avoid everything else
3-6 months late: £200 in fixed penalties, but you'll avoid the percentage penalties
6-12 months late: You'll face percentage penalties, but filing now prevents the 12-month penalty from hitting
Over 12 months late: File immediately. The penalties are already substantial, but continuing to not file only makes things worse

After filing, you can appeal the penalties if you had a reasonable excuse. But file first — don't let the appeal process delay you further.

Full penalty breakdown: What happens if you miss the CT600 deadline

How to Tell HMRC Your Company Is Dormant

If your company genuinely has had no transactions and you want to avoid future CT600 filing obligations, here's how:

File any outstanding CT600s — clear your backlog first
Write to HMRC at the Corporation Tax Services address for your area, or call the Corporation Tax helpline (0300 200 3410)
State that your company is dormant and has had no business transactions
Provide the date the company became dormant
HMRC will confirm in writing that they've marked the company as dormant

Once dormant, HMRC won't issue notices to file. But if your company later becomes active (even just earning bank interest), you must tell HMRC immediately and resume filing.

Frequently Asked Questions

Do I need to file a CT600 if my company made a loss?

Yes. A company that traded but made a loss must file a CT600 reporting that loss. This is actually in your interest — filing the return formally records the loss with HMRC, which you can then carry forward to offset against future profits and reduce your tax bill. The penalties for not filing apply regardless of whether you owe tax.

Do I need to file a CT600 for a dormant company?

It depends. If HMRC has formally agreed that your company is dormant and removed it from their active register, you don't need to file. But if you haven't contacted HMRC to tell them your company is dormant, they're still expecting returns — and penalties are accumulating. Filing dormant accounts at Companies House does NOT satisfy your HMRC CT600 obligation.

What counts as "dormant" for HMRC corporation tax purposes?

For HMRC, dormant means your company has had zero business transactions — no income, no expenses, no bank interest, nothing. Even a small amount of bank interest makes your company active. This is stricter than Companies House's definition of dormant, which allows shares issued on formation and filing fees.

Can I file a CT600 with zero turnover?

Yes, and this is very common. Thousands of companies file CT600 returns every year showing zero turnover. The return simply confirms to HMRC that your company had no taxable activity. You still need to submit iXBRL-tagged accounts alongside the return.

How do I file a nil CT600 return?

The easiest way is to use Taxpipe. Sign up, enter your company details, confirm you had no trading activity, and we generate and file the complete CT600 with iXBRL accounts. It takes about 10-15 minutes and costs £59. Alternatively, you can use other CT600 software or an accountant, but those options are typically more expensive.

What happens if I don't file a CT600 for a nil return?

The same penalties apply as for any late CT600: £100 at 1 day late, another £100 at 3 months, 10% of tax at 6 months, and 20% at 12 months. Since your tax bill is £0, the percentage penalties won't add anything — but the fixed £200 in penalties still applies. And if you're a serial late filer, daily penalties of £10/day can add another £900.

My company only earned bank interest. Do I need to file?

Yes. Bank interest is taxable income for corporation tax purposes. You need to file a CT600 reporting this income and pay the corporation tax due on it. Even if the interest is just £10, the filing obligation exists. See our bank interest and corporation tax guide for details.

I formed my company but never traded. Do I still need to file?

Yes — unless you've contacted HMRC and they've agreed to mark your company as dormant. HMRC is automatically notified when you incorporate and will expect CT600 returns. If you never intend to trade, contact HMRC to go dormant as soon as possible.

How much does it cost to file a nil CT600?

With Taxpipe, it costs £59 — the same price whether your company made £1 million or £0. An accountant might charge £200-£500+ for the same thing. Some other software options range from £80-£200. Taxpipe is the most affordable way to stay compliant.

Can I carry forward a loss if I file late?

Yes, filing late doesn't prevent you from carrying forward the loss — but it does attract penalties. The loss claim itself isn't affected by the timing of the filing, as long as you file within 4 years of the end of the accounting period. However, you should file on time to avoid unnecessary penalties and to ensure HMRC has your loss on record.

Don't Risk Penalties for a £59 Return

If your company made no profit — whether through trading losses, dormancy, or simply not having started yet — the CT600 filing obligation doesn't go away. The penalties for not filing are the same whether you owe tax or not.

Taxpipe makes nil returns and loss-making returns just as easy as profitable ones:

✅ £59 flat fee — same price for every company
✅ iXBRL accounts included — no extra software needed
✅ Loss declarations handled — protect your future tax position
✅ 15-minute process — plain English questions, no accounting jargon
✅ Direct HMRC submission — filed instantly, confirmation receipt provided

File your nil return now → | See pricing → | Calculate your tax →

The cost of filing: £59. The cost of not filing: at least £100 in penalties, a messy compliance record, and the stress of dealing with HMRC. The choice is obvious.

Do I Need to File a CT600 If My Company Made No Profit?