Self-assessment tax returns are a given for company directors, so you need to be aware that there’s a new requirement for the 2025/26 tax year that you need to be aware of.

HMRC has introduced additional boxes on the employment pages of the self-assessment return, requiring directors to declare their shareholding in any close company in which they have an interest.

This is a change that affects a significant number of people, and missing it could result in penalties.

What is a close company?

A close company is broadly defined as a UK-resident company that is controlled by five or fewer shareholders, or by its directors. Most small and medium-sized limited companies in the UK fall into this category. If you run or are involved in a typical owner-managed business, it is likely to be a close company.

What’s changed?

For the 2025/26 self-assessment return, HMRC has added new boxes to the employment pages requiring directors to provide details of any shareholding they hold in a close company in which they have an interest. This applies to all relevant directorships, not just the company you might consider your primary one.

The purpose is to give HMRC greater visibility over the ownership structure of close companies, and to make it easier to identify situations where income or benefits may not have been fully reported.

Why does this matter?

The keyword here is penalties.

If the required information is not included on your return, HMRC has indicated that penalties will be issued. This is not an optional disclosure or a box that can simply be left blank – it is a mandatory requirement for the 2025/26 return.

It’s also worth being clear about what “any close company you have an interest in” means in practice. This isn’t limited to companies where you are the sole director or majority shareholder. If you hold shares in multiple companies – even as a minority shareholder – you may need to include details of each one.

What you need to do

If you use an accountant to prepare and file your self-assessment return, the most important thing you can do right now is make sure they have a full picture of your directorships and shareholdings.

In particular, let your accountant know if you are a director or shareholder of any company that they may not already be aware of. This includes companies that are dormant, companies you may have a small or passive shareholding in, and companies you have been appointed to more recently.

If your accountant doesn’t know about a company, they cannot include it on your return. And if it’s not on the return, the penalty risk falls on you.

A simple checklist

Before your 2025/26 return is prepared, it is worth running through the following:

  • Are you a director of more than one company?
  • Do you hold shares in any company other than your primary trading company?
  • Have you been appointed as a director or acquired shares in a new company since your last return was filed?
  • Are you involved in any dormant or holding companies?

If the answer to any of these is yes, make sure your accountant has that information before your return is submitted.

Get in touch

If you’re unsure whether this new requirement affects you, or if you’d like to review your self-assessment position ahead of the 2025/26 filing season, we’re happy to help. Call us on 01472 357125 or contact us through the website