CT600H guide

CT600H: cross-border royalties, withholding, and treaty relief evidence.

A practical guide for UK companies and advisers preparing CT600H where cross-border royalty payments are disclosed with the Corporation Tax return.

What CT600H is for

CT600H is the HMRC supplementary page for cross-border royalties. HMRC's form guidance says to use CT600H where a UK company made cross-border royalty payments and reasonably believed that the recipient would be entitled to treaty relief on any tax deducted.

In practice, CT600H is about disclosure discipline. The company needs a clear trail showing who received the royalty, what was paid, what withholding position was taken, and why treaty relief was believed to apply.

When CT600H may be needed

CT600H is relevant for UK companies with cross-border royalty payments in the accounting period. It is not enough to know that a payment left the UK; the filing team also needs to understand whether the payment is a royalty, who received it, and how any treaty position was judged.

  • The payer is a UK company filing a CT600.
  • The company made cross-border royalty payments in the accounting period.
  • The company reasonably believed the recipient would be entitled to treaty relief on tax deducted.
  • The recipient, royalty type, gross amount, and tax deducted need to be disclosed.
  • The CT600 supplementary-page indicator must agree with the filing output.

What information belongs in the CT600H review

A strong CT600H workflow captures the transaction detail and the reasoning behind the withholding position. That is especially important where a payment is one of several connected-party charges, intellectual-property licences, or overseas group arrangements.

  • Name and address of the royalty recipient.
  • The type of royalty payment made.
  • The gross amount of royalty paid.
  • The amount of UK tax deducted, if any.
  • The country and treaty basis considered by the reviewer.
  • Evidence supporting the reasonable-belief position.

The reasonable-belief point

The phrase "reasonably believed" matters. CT600H is not a substitute for doing the treaty and withholding analysis. It is the supplementary page that records the cross-border royalty detail when the company has taken a treaty-relief position on tax deducted.

For accounting practices, the file should show the source of the belief: contract review, recipient residence evidence, treaty article considered, clearance or direction where relevant, and the amount of tax withheld or not withheld. That evidence can be more important than the form fields themselves if the position is queried later.

How Robocount handles CT600H workflow

Robocount keeps CT600H inside the Corporation Tax review workflow so cross-border royalty detail can be checked with the main CT600, computations, attachments, and filing output.

  • Captures royalty entries and payment-level detail.
  • Tracks recipient, royalty, gross payment, and withholding information for review.
  • Connects treaty and reasonable-belief notes to the filing pack workflow.
  • Keeps the CT600H indicator aligned with the supplementary page included in the return.
  • Supports API and AI-assisted workflows where royalty data needs structured review before filing.

Review checklist before filing

  • Classify the payment and confirm it is a royalty for CT600H purposes.
  • Confirm the recipient details and country information are complete.
  • Review the treaty-relief reasoning and supporting evidence.
  • Check gross payment and tax deducted figures against the ledger and working papers.
  • Make sure the main CT600 indicator and CT600H output agree.

FAQ

Is CT600H needed for every overseas payment?

No. CT600H is specifically for cross-border royalty payments in the circumstances covered by HMRC's CT600H guidance. Other overseas payments may need different tax analysis but not this page.

Does CT600H prove treaty relief is correct?

No. CT600H records relevant disclosure information. The company still needs support for the treaty and withholding position, including why it reasonably believed relief applied.

Why does this matter for AI or API filing?

Cross-border royalty fields are structured but judgment-heavy. An AI or API workflow should collect the transaction data and force a human review of the treaty-relief evidence before the CT600 package is submitted.

Useful HMRC references

This guide is general product and filing workflow information, not tax advice. Check the current HMRC guidance and the company's treaty and withholding facts before filing.