What CT600H is for

CT600H is the HMRC supplementary page for cross-border royalties. 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.

CT600H box and data-entry checklist

Robocount uses the MDD to separate return details, entered royalty data, and calculated filing indicators. The CT600H fields should still be tied back to the royalty contract, ledger, withholding analysis, and treaty evidence before filing.

H1: Company name. Prefilled from the return record so the supplementary page matches the main CT600.
H2: Tax reference. Prefilled from the company's CT600 tax reference.
H3: Period from. Prefilled from the accounting period start date used on the main CT600.
H4: Period to. Prefilled from the accounting period end date used on the main CT600.
Royalty recipient name. Enter the actual recipient of the royalty, not just the supplier group or invoice contact.
Recipient address. Enter the recipient's full address so residence and treaty evidence can be reviewed.
Payment type. Enter the royalty type, for example intellectual property, software, trademark, franchise, patent, or another licence payment.
Amount. Enter the gross royalty amount for the period and reconcile it to the ledger, invoices, bank records, and computation.
Agreement or treaty basis. Select or record the relief basis used for the withholding position.
Deduction rate. Enter the withholding rate applied to the payment.
Deduction amount. Enter the amount of UK tax deducted from the royalty payment.
Additional notes. Use this for reviewer context such as treaty article, HMRC direction, clearance, mixed-payment split, or other explanation that supports the filing position.
Main CT600 box 130. Calculated from the CT600H royalty data and filing package state; it should not be treated as a loose manual tick.

This guide focuses on CT600H because Robocount's product metadata has a structured royalty data model and the HMRC filing builder emits the CT600H body when royalty rows are present. If box 130 is set, the CT600H entries, royalty expense treatment, withholding support, and computation should all reconcile.

Royalty classification triage

CT600H should not be driven by keyword matching alone. Words like licence, software, platform, IP, hosting, support, recharge, and subscription can point to different tax treatments depending on the contract and what the UK company actually received.

Pure royalty. A payment for the right to use intellectual property is the clearest CT600H candidate and needs recipient, treaty, gross payment, and withholding support.
Mixed invoice. If one invoice covers licence rights, support, implementation, hosting, or maintenance, split the analysis before completing the payment type and amount fields.
Connected-party charge. Check whether the royalty review also needs transfer-pricing support, beneficial ownership evidence, and an intercompany agreement.
Marketplace or reseller payment. Identify the actual recipient and whether the payment is a royalty, commission, service fee, or onward recharge.
No withholding deducted. Treat nil withholding as a review trigger, not as an administrative detail. The evidence should explain the treaty, direction, clearance, or other basis relied on.

This is where CT600H differs from many other supplementary pages: the form asks for compact payment details, but the filing risk usually sits in classification and treaty reasoning. Robocount surfaces uncertain classifications before the return is approved, so reviewers can resolve the tax treatment while the evidence is still in front of them.

How to enter CT600H details in Robocount

In Robocount, enter CT600H from the return workspace after the royalty payment has been identified from the ledger, contract, or intercompany recharge review.

Open the return and go to Data Entry, then choose the Supplementary section.
Add a CT600H royalty row; Robocount then keeps the supplementary page aligned with main CT600 box 130.
Enter the recipient name and address, using the actual royalty recipient rather than only the invoice contact.
Enter the royalty type, gross royalty paid, treaty or agreement basis, withholding rate, and tax deducted.
Use the additional-notes field or evidence note to record the treaty article, HMRC direction, clearance, nil-withholding explanation, or mixed-invoice split.
Attach or reference the contract, invoice, payment record, recipient-residence evidence, and any intercompany agreement.
Run Compute and Validate, then clear any warnings about missing treaty evidence, nil withholding, or inconsistent gross-payment figures.

Client intake questions for royalties

CT600H cases often start as ordinary ledger entries: licence fees, intellectual property charges, software royalties, franchise payments, brand fees, or connected-party charges. The intake process needs to force the right tax questions before the return reaches final review.

Was the payment a royalty or a different type of overseas service, subscription, recharge, or management fee?
Who was the beneficial recipient of the payment, and where was that recipient resident?
Was UK tax deducted, and if not, what treaty or clearance basis was relied on?
Is there a contract, invoice, payment record, or intercompany agreement supporting the classification?
Has the reviewer considered whether additional royalty-payment penalty provisions could be relevant?

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.

Withholding and treaty evidence pack

A strong CT600H file does not simply state that treaty relief was available. It shows the route to that conclusion. HMRC's CT600H guidance asks for details of payments made and highlights additional penalty provisions where royalty-payment rules are not observed, so the evidence pack should be practical and durable.

Contract or licence agreement showing the nature of the royalty.
Recipient name, address, country, and beneficial ownership review notes.
Double Taxation Agreement country considered and the rate used.
Tax deducted, tax not deducted, or reduced-rate withholding calculation.
Any HMRC direction, clearance, treaty passport evidence, or adviser note relied on.
Ledger, bank, invoice, and intercompany recharge support for the gross payment figure.

Main CT600 and computation checks

CT600H sits alongside the main return, but the royalty expense may also affect taxable profits, transfer pricing files, related-party disclosures, and withholding-tax controls. The reviewer should not treat the supplementary page as a standalone schedule.

Confirm the CT600H indicator agrees with the supplementary page included in the filing package.
Trace the gross royalty amount to the accounts, tax computation, and supporting payment records.
Check whether the royalty deduction itself has been reviewed separately from withholding disclosure.
Review connected-party cases for transfer pricing or supporting intercompany agreement evidence.
Keep the treaty-relief conclusion with the CT600 approval pack, not only in a tax memo.

Common CT600H traps

The first trap is assuming every overseas technology or software payment is a royalty. Classification matters. Some payments may be subscriptions, services, licence fees, mixed supplies, or cost recharges, and the CT600H conclusion should be based on the facts.

The second trap is recording the country but not the treaty logic. HMRC asks for the country with the Double Taxation Agreement, but the practice file should also show why the reviewer believed the recipient was entitled to treaty relief.

The third trap is letting payment-level detail drift from the ledger. If multiple payments were made to the same recipient, the CT600H entries should be reconciled to gross amounts and tax deducted for the period covered by the supplementary page.

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.

Example review scenarios

Connected company IP licence

A UK company pays a group company for the right to use software, trademarks, or other intellectual property. The CT600H review should capture the recipient, agreement, gross payments, withholding position, treaty basis, and any transfer-pricing support.

Mixed overseas invoice

An overseas invoice includes support services, hosting, and a licence charge. Do not push the whole invoice into CT600H by default. Split the payment analysis and document which element, if any, is treated as a royalty.

AI-assisted ledger classification

If an AI workflow spots royalty-like descriptions, use that as a triage signal only. A reviewer still needs to confirm classification, treaty evidence, gross amount, and withholding treatment 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.
Record who approved the treaty-relief conclusion and where the support is stored.

AI and API workflow controls

CT600H data can be structured, but the judgment behind it should not be hidden. Robocount is designed so imported royalty payments can be held for review until the evidence and approval state are clear.

Flag overseas payment descriptions that look royalty-related for human review.
Require recipient country, gross amount, and tax deducted fields before page completion.
Warn where treaty-relief notes are absent but no UK tax has been deducted.
Keep the filed CT600H output tied to the transaction evidence and approval pack.

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.

What if no UK tax was deducted?

The review needs to show why that was appropriate. CT600H is especially sensitive where the company relied on treaty relief, a direction, or another reasonable-belief basis for reduced or nil withholding.

Can one CT600H entry cover multiple payments?

The filing team should follow the current form structure and keep enough payment-level support to reconcile the disclosed gross amount and tax deducted. Do not lose the underlying transaction trail.

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.

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