A scheme for the self-assessment of tax by companies. In the UK, self-assessment of corporation tax was introduced for all companies with an accounting period ending after 1 July 1999. Tax returns must be completed and filed within 12 months of the end of the accounting period. Smaller companies must pay their tax liability within nine months of the end of the accounting period; large companies must make payments on account in advance of this date.
Subjects: Financial Institutions and Services — Accounting.