Companies must submit a corporation tax return within 12m of their period end
They must pay the tax within 9m + 1day of their period end (CAP) but they do not have to file their return until 12 months after the CAP end.
Therefore many submit their corporation tax return before the 9m + 1day payment deadline too
Features of self assessment for companies
Must be done online
Financial statements are submitted along with it - using iXBRL
Inline eXtensible Business Reporting Language (iXBRL)
iXBRL allows for the exchanging of business information electronically and tags the accounts so they can be read by a computer
HMRC then uses online software which produces iXBRL information.
Integrated Software Applications
These automatically insert the iXBRL tags and produces accounts/computations in the iXBRL format
Managed Tagging Services
Company outsources this tagging process
Applies tags and so converts the info into iXBRL