• 2 May, 2025
• HMRC CT600
• Reading time: 2mins
• By FinTags UK

Joint Filing for Companies House and HMRC Ends in March 2026 – Save Time with These Tips

For finance professionals, companies, CFOs, clients, and investors, keeping up with regulatory changes is critical to ensure compliance and streamline operations. One significant change on the horizon is the closure of the joint filing service for company accounts between Companies House and HM Revenue & Customs (HMRC). This service, in place since 2011, has been a valuable tool for simplifying the filing process, but it’s set to end in 2026.

In this blog post, we’ll break down what the joint filing service is, why it’s closing, how it affects you, and how to prepare for the transition in a clear and straightforward way.

What is the Joint Filing Service?

The joint filing service allows companies, particularly small businesses with straightforward financial affairs, to submit their annual accounts to both Companies House and HMRC using a single online platform. This includes statutory accounts for Companies House (full, abbreviated, or dormant) and the Company Tax Return (CT600) for HMRC. By entering data once, companies avoid duplicating efforts, saving time and reducing the risk of errors. The service, accessible through HMRC’s Online Services, requires a Government Gateway user ID and password, as well as a Companies House authentication code. It automatically converts accounts to Inline XBRL (iXBRL) format for HMRC, ensuring compliance with digital filing requirements.

The service has been particularly beneficial for:

• Small companies with simple finances.
• Incorporated charities filing their own accounts.
• Dormant companies submitting basic accounts.

Since its launch in 2011, it has streamlined compliance for many businesses, especially those filing frequently, by offering a one-stop solution for meeting regulatory obligations.

Why is the Service Closing?

The joint filing service is scheduled to close on 31 March 2026 because it no longer meets the needs of modern regulatory frameworks. Several factors contribute to this decision:

• Outdated Technology: The service doesn’t align with current digital standards, making it less efficient compared to newer systems.
• Enhanced Corporation Tax Requirements: HMRC’s updated tax rules require more robust and flexible filing solutions that the joint service cannot support.
• Economic Crime and Corporate Transparency Act 2023 (ECCTA): Changes to UK company law under the ECCTA, such as stricter identity verification processes, are not compatible with the current service.
• Support for New Measures: Closing the service allows Companies House to implement ECCTA-driven reforms, like enhanced checks to prevent economic crime, aligning with international best practices.

This closure reflects a broader shift toward modernized, secure, and standardized digital filing processes across the UK.

How Will This Affect You?

The closure of the joint filing service will impact how companies manage their compliance obligations. Here’s what you need to know:

• • Separate Filings Required: From 1 April 2026, you’ll need to file your annual accounts with Companies House and your Company Tax Return with HMRC separately. This applies to all entities currently using the joint service, including small companies, incorporated charities, and dormant companies.

Filing Methods:

• • Companies House: You can file using third-party software, Companies House web services, or paper filing (though software is encouraged for efficiency).
  • HMRC: You must use commercial software to file your Company Tax Return, as paper filing is only allowed in exceptional cases (e.g., reasonable excuses or filing in Welsh, requiring form WT1).
• Access to Previous Filings: After the closure, you won’t be able to access previously filed returns through the joint service. It’s recommended to download and save at least the last three years’ filings for compliance checks or future reference.
• Impact on Workflow: Companies that rely on the service’s convenience may face increased administrative effort. However, modern software solutions can mitigate this by offering flexibility and additional business support features.

The table below summarizes the key changes:

How to Prepare for the Transition

To ensure a smooth transition, companies should take proactive steps now:

• Explore Software Options: Start researching approved software suppliers for filing with both Companies House and HMRC. Lists of suppliers are available at HMRC – Corporation Tax Software and GOV.UK – Company Accounts Software.
• Save Past Filings: Download and store copies of at least the last three years’ filed returns using HMRC’s Online Services before the closure date.
• Understand New Requirements: Ensure your accounts are balanced (total assets match liabilities) and familiarize yourself with the iXBRL format for HMRC filings.
• Plan Early: Transition to software-based filing now to avoid last-minute challenges. This is especially important for companies with frequent filings or complex compliance needs.
• Stay Informed: Sign up for newsletters from Companies House and HMRC to receive updates on filing changes and ECCTA implementation. Visit GOV.UK Newsletters for subscriptions.

For companies using accountants or tax advisers, share your Companies House authentication code to streamline the process. If you’re a charity or community interest company, check specific filing requirements, as they may differ.

Future of Filing

The closure of the joint filing service is part of a larger move toward fully digital and standardized filing processes. Companies House plans to eventually require all account filings to be submitted via software, with at least 21 months’ notice before this change takes effect. This aligns with global trends toward digital compliance and supports efforts to enhance transparency and prevent economic crime. By adopting modern software solutions, companies can not only meet regulatory requirements but also gain access to tools that offer data analytics and business insights, improving overall financial management.

Contact FinTags today for 30 minutes AI XBRL tagging for your company accounts and tax computations. Learn more at www.fintags.ai