A company authentication code is a six-character code that Companies House issues to each company. It is needed to file information online or through software, including the annual accounts.
What it is
The company authentication code is a six-character code of letters and numbers. It acts as the company’s signature for electronic filings, so Companies House knows a filing is authorised. It is posted to the company’s registered office address.
Using it
You need the code to file accounts with software such as Tax Optimiser. Anyone with the code can file for the company, so share it only with people you trust to file, such as your accountant. If it is lost, request a new one from Companies House; the letter can take up to five working days.
Read more: Your Companies House authentication code.