October 20, 2025
By Merranti

CT61 Returns Explained: What They Are, Who Needs One, and When They’re Due

When running a business, there are numerous tax obligations to stay on top of. While most companies are familiar with corporation tax, VAT, PAYE and Self Assessment, CT61 returns are a lesser-known but important part of the UK tax system for certain companies.

In this article, we’ll explore in detail what CT61 returns are, when they apply, which payments trigger them, how to file one, and what to do if you’ve suffered or deducted tax. This guide is relevant to UK companies and other corporate entities that may be paying interest, royalties, or other annual payments where withholding tax rules apply.

1. What is a CT61 Return?

A CT61 return is a quarterly tax return filed with HMRC by UK companies or other corporate bodies that have deducted income tax at source from specific payments.

These payments are typically:

Interest payments
Royalties
Compensation payments are treated as annual interest
Certain other annual payments with a UK source

In these cases, the payer acts as a tax collector on behalf of HMRC, deducting tax from the payment before it reaches the recipient and then sending that tax to HMRC using a CT61 form.

This obligation comes from the Income Tax Act 2007, specifically section 874, which requires companies to withhold tax from payments of yearly interest or annual payments, unless a specific exemption applies.

The rate of tax deducted is normally the basic rate of income tax – currently 20% (as of the 2025/26 tax year).

2. When Does a CT61 Return Apply?

A CT61 return is required only if your company has made payments from which tax must be withheld. This usually involves payments of yearly interest that have a UK source and are paid to:

Individuals
Overseas companies or entities
Partnerships (where not all members are UK companies)
Other non-exempt entities

Examples of payments that require a CT61 return:

Your company pays interest to a director on a loan they’ve made to the company
You pay interest on a loan from an overseas company
You pay interest to an individual investor
You pay royalties to an overseas individual or business (e.g., for using their intellectual property)

In all of these scenarios, you’re required to deduct 20% tax before making the payment and report and pay the tax using a CT61 form.

3. When Is a CT61 Return NOT Required?

There are several exemptions and reliefs where tax withholding (and therefore CT61 reporting) does not apply.

These include:

Interest paid to another UK company
Short interest (on loans lasting less than 12 months)
Interest on quoted Eurobonds
Interest on qualifying private placements
Interest on peer-to-peer (P2P) loans
Distributions from Investment Trusts, OEICs or AUTs

It’s also important to note that domestic transactions between UK companies usually don’t involve withholding tax – one of the most common misunderstandings is that tax must always be withheld from interest, which is not the case when both payer and recipient are UK-resident companies.

4. What Is ‘Yearly Interest’?

The term ‘yearly interest’ refers to interest arising on a loan or debt that could last more than 12 months. It doesn’t matter if it actually does last that long – only that it could.

In contrast, ‘short interest’, i.e., interest on loans expected to be repaid in less than a year, is typically not subject to withholding tax.

For example:

A 3-year director’s loan to a company would involve yearly interest – withholding applies.
A short-term loan of 6 months? That’s short interest – no withholding required.

5. What Counts as a UK Source?

HMRC generally considers the residence of the debtor (payer) and the location of enforceability of the debt as determining whether the interest is UK-sourced.

For example:

If a UK company pays interest to an overseas lender, that payment has a UK source, and withholding applies unless a treaty exemption or clearance is obtained.

6. Filing Periods for CT61 Returns

CT61 returns follow quarterly accounting periods, typically aligned with the calendar year:

1 January to 31 March
1 April to 30 June
1 July to 30 September
1 October to 31 December

However, if your company’s year-end is different from these quarters (e.g. 31 May), you may have five CT61 return periods within your accounting year:

1 June to 30 June
1 July to 30 September
1 October to 31 December
1 January to 31 March
1 April to 31 May

Each return is due 14 days after the end of the relevant period.

Note: If no tax is deducted during the period, you don’t need to file a nil return. Only companies that have actually withheld tax must file CT61.

7. How to Get and Submit a CT61 Form

CT61 returns are not downloadable from the HMRC website.

Instead, they must be requested online via the HMRC website or your Government Gateway account.

HMRC will send you a paper copy, which includes a unique reference number linked to your company. This number is essential to ensure your payments are allocated to the correct account.

Once submitted, HMRC will continue to send a CT61 form each quarter unless you notify them that one is no longer needed.

8. Payments and Repayments

At the end of each quarter:

You calculate the total tax you’ve deducted from payments
You calculate any tax you’ve suffered on receipts (i.e., received income that had tax withheld)

Then, you compare the two:

If you withheld more than you suffered, you pay the balance to HMRC.
If you suffered more than you withheld, you can reclaim the excess or carry it forward to offset future quarters or corporation tax.

However, HMRC will only repay tax up to the amount you’ve already paid in during the accounting period. Any excess is carried forward or deducted from your final corporation tax liability for the year.

9. Interest and Penalties

HMRC charges interest on late payments of tax due under CT61. The interest:

Runs from the due date (14 days after quarter-end) until payment is made
Is not subject to withholding
Is deductible for corporation tax purposes

If HMRC believes your return is incomplete or incorrect, they may issue an assessment to the best of their judgment. This assessment becomes due 14 days after issue.

If you’ve overpaid tax, interest is paid to you by HMRC, but it must be declared as taxable income in your company accounts.

10. Director Loan Example

One of the most common CT61 scenarios involves director loans.

Say a director lends money to their company and agrees to receive interest (as a return on the loan). If the loan is open-ended or extends beyond 12 months, the interest is yearly interest and subject to 20% withholding tax.

The company must withhold tax.
File a CT61 return
Pay the tax to HMRC
Provide the director with a statement of tax withheld, which they can use to claim credit on their own Self Assessment return

11. Double Tax Relief and Treaties

If the interest is paid to a recipient in a country with which the UK has a double tax treaty, a reduced withholding rate may apply – often 0%, 10%, or 15%.

To apply the treaty rate:

The recipient must submit a claim to HMRC
HMRC must approve the claim
Only then can you pay the interest gross or at a reduced rate

Always ensure this paperwork is complete before making any gross payments.

Final Thoughts: Does Your Company Need to File a CT61?

If your company is paying interest or royalties to individuals, overseas entities, or mixed partnerships, there’s a strong chance you may need to file a CT61 return and withhold tax.

It’s vital to:

Identify whether the payment is a yearly interest
Check if the recipient qualifies for exemption
Deduct tax if required
File the CT61 on time

Failure to comply can result in penalties, interest charges, and issues with HMRC audits.

Need Help?

CT61 obligations can be confusing, especially if you don’t make such payments regularly. At Merranti Accounting, we can:

Review whether a CT61 is required
Assist with completing and submitting the form
Help you navigate double tax treaties
Ensure timely compliance to avoid penalties

Contact us today for clear, practical advice tailored to your company’s circumstances.