What is CATO HMRC?
Company Accounts and Tax Online (CATO) has been operating since 2011 on the HMRC website as a free online filing service intended for micro companies to do the following:
- Submit their corporation tax return (CT600) online to HMRC
- Submit their annual abridged accounts to Companies House
- Submit their CT600 to HMRC and abridged accounts to Companies House all under one service.
When does it close?
The Company Tax and Online Accounts service is closing permanently on 31 March 2026, and businesses who have been using CATO need to prepare for this change to ensure that they continue to meet tax filing obligations. Government advice states that businesses should download their last three years of company accounts before the closure[1], as after March next year these accounts will no longer be available on the system, and businesses will not be able to submit their CT600 return or annual accounts using this service.
Why is the online service closing?
HMRC announced that the service is closing "Because it’s now outdated. It no longer aligns to modern digital standards, enhanced corporation tax requirements or changes to UK company law under the Economic Crime and Corporate Transparency Act (ECCT act)."[2]This reform aims to strengthen the business environment, improve national security, and combat economic crime.
Can I file Ltd company accounts myself?
You are legally allowed to prepare your own limited company accounts and submit them to HMRC and Companies House. However, it's important that the person handling the submissions has a solid understanding of accounting principles. Since not all directors have prior accounting knowledge, the UK Government recommends businesses choose from a list of approved software providers for CT600 filing and annual company accounts.
Do I need accounting software for my business?
With the imminent change, companies are being strongly encouraged to use third party software to ensure accuracy and meet tax compliance obligations; but there are not many available options for companies to create and submit their filings simultaneously to Companies House and HMRC. This means that companies will often need to purchase more than one product to meet their filing needs and create separate submissions, and why Easy Digital Filing has created our own CATO joint filing service to help companies save time and provide streamlined record keeping.
What do I need to file?
Using third party software, businesses will need to submit the following filings annually:
- Corporation tax return (CT600) to HMRC
- Fully tagged iXBRL accounts
- Abridged accounts to Companies House
These filings are available as a bundle on our filing platform starting at £139 + VAT for micro accounts, allowing you to submit filings to both HMRC and Companies House including one set of Micro iXBRL accounts, one CT600, and one Companies House submission; making it easy to submit everything in one place, just like using CATO.
What is the CATO joint fing service?
Our joint filing service has been designed for small businesses to file to both Companies House and HMRC online, complete with iXBRL computations to accompany the CT600 tax calculation along with fully tagged iXBRL accounts for both small and micro companies. Our software is cloud based, meaning you can log on anywhere with nothing to download, and our simple to use platform allows you to save in progress templates until you are ready to file. We also have an expert team of in-person account specialists based at our London office, available on live chat Mon-Fri.
Looking For Further Information?
If you’d like more details about the CATO closure, please check out our other article on the CATO closure. You can register for free and explore our platform templates for as long as you like - there’s no charge until you’re ready to submit your filings. If you have any questions about how our software can accommodate your annual filing needs, feel free to get in touch and we'll be happy to assist.
[1] https://www.gov.uk/guidance/closure-of-the-service-to-file-your-company-accounts-and-tax-return
[2] https://www.gov.uk/government/news/the-online-accounts-and-company-tax-return-service-is-closing
