CT600 Supplementary Pages: Which Ones Do You Need?
The main CT600 form covers basic company information, income, and tax calculation. But depending on your circumstances, you may also need to file one or more supplementary pages.
Don't worry — most small companies need none or just one. Here's the complete guide.
Quick Decision Table
| Page | You Need It If... | Most Small Companies? |
|---|---|---|
| CT600A | You have trading losses | Sometimes |
| CT600B | You're claiming group relief | Rarely |
| CT600C | You have capital gains/losses | Sometimes |
| CT600D | You have overseas income or dual residence | Rarely |
| CT600E | You're a charity or CASC | Rarely |
| CT600F | You have loan relationships or derivative contracts | Sometimes |
| CT600G | You're in a tonnage tax scheme | Almost never |
| CT600H | Cross-border royalties (EU Interest & Royalties Directive) | Almost never |
| CT600I | Supplementary charge for oil & gas | Almost never |
| CT600J | Disclosure of tax avoidance schemes | Almost never |
CT600A: Losses, Deficits and Excess Amounts
File this if your company has:
- Trading losses to carry forward or carry back
- Non-trading loan relationship deficits
- Excess management expenses
- UK property business losses
When Most Companies Need It
If your company made a loss in the current period, or is using losses from a previous period, you need CT600A. This is the most commonly filed supplementary page for small companies.
Key Boxes
- Box A1: Current period trading loss
- Box A5: Trading losses carried back
- Box A10: Trading losses carried forward
- Box A35: Non-trading loan relationship deficit
CT600B: Group Relief
File this if your company is part of a group and is either surrendering or claiming losses between group members.
When You Need It
Group relief allows profitable companies in a group to offset losses from loss-making group companies. Both the surrendering and claiming companies file CT600B.
Most single-company directors will never need this page.
CT600C: Capital Gains
File this if your company:
- Sold shares, property, or other chargeable assets at a profit (or loss)
- Received capital distributions
- Needs to report capital losses
Key Points
- Company capital gains are taxed at the normal corporation tax rate (not the CGT rates that individuals pay)
- Capital losses can only be offset against capital gains, not trading profits
- The annual exempt amount for individuals does NOT apply to companies
CT600D: Overseas Income and Foreign Tax Credit
File this if your company:
- Receives income from overseas sources
- Is claiming Double Taxation Relief (foreign tax credit)
- Is dual-resident (resident in the UK and another country)
Most UK-only companies don't need this page.
CT600E: Charities and Community Amateur Sports Clubs
File this if your organisation is a registered charity or CASC claiming tax exemptions.
CT600F: Loan Relationships and Derivative Contracts
File this if your company has complex financial instruments beyond simple bank interest:
- Corporate bonds
- Inter-company loans with non-trivial terms
- Derivative contracts (options, futures, swaps)
- Foreign currency gains/losses on financial instruments
Note on Bank Interest
Simple bank interest (from a current or savings account) does NOT require CT600F. It's reported in the main CT600 body (box 170).
CT600G, H, I, J
These are specialist pages for tonnage tax, cross-border royalties, oil & gas, and disclosure of tax avoidance schemes. If you need any of these, you almost certainly have professional advisers already.
What If I'm Not Sure?
If your company is a straightforward trading company with:
- No losses to claim
- No capital gains
- No overseas income
- No group companies
Then you likely need no supplementary pages at all. Just the main CT600 form.
Filing software like Taxpipe asks the right questions and automatically determines which supplementary pages are needed based on your answers.
Key Takeaways
- Most small companies need 0-1 supplementary pages
- CT600A (losses) is the most common for small companies
- CT600C (capital gains) is needed if you sold assets
- CT600B-J are for specialist situations
- Filing software determines which pages you need based on your data
Let Taxpipe Handle It
Taxpipe's guided wizard determines which supplementary pages your company needs and includes them automatically. No guesswork required.
File your CT600 → — £59, all supplementary pages included.