Guernsey Corporate Income Tax Return
Annual company tax return filed with the States of Guernsey Revenue Service. Due 6 months after the end of the company's accounting year. All Guernsey-incorporated companies must file, even if their tax liability is nil under the 0% standard rate.
Who this applies to
- All companies incorporated in Guernsey
- Companies tax-resident in Guernsey by management and control
- International Business Entities (IBEs)
- Exempt companies
- Companies subject to the 10% rate (financial services licensees)
What to file
Company tax return (forms ET1 or ET3 depending on company type) including profit and loss account, balance sheet, income reconciliation, economic substance declaration, and details of any related party transactions.
How to file
Online via the Revenue Service online portal at taxreturn.gov.gg. First-time filers must register the company. Some advisers file on behalf of their clients using agent access.
Payment due
Tax assessed (if any) is due 30 days after the date of the Revenue Service assessment notice, which is typically issued after the return is processed.
Penalties for missing this deadline
£300 late filing penalty immediately on the missed deadline; a further £300 if still not filed after 30 days; escalating penalties thereafter. Interest accrues on unpaid tax at the statutory rate.
Filing checklist
- Prepare statutory accounts (profit and loss, balance sheet) for the accounting year
- Reconcile accounting profit to taxable profit (add back non-deductible costs, deduct exempt income)
- Complete the economic substance declaration for relevant activities
- Disclose related party transactions and director loan accounts
- Apply the correct tax rate: 0%, 10%, or 20% (Guernsey property income)
- File online via taxreturn.gov.gg by the 6-month deadline
- Pay any assessed tax within 30 days of the assessment notice
Common mistakes to avoid
- Failing to file even though the company owes 0% tax — the filing obligation exists regardless
- Not including the economic substance declaration for holding companies or IP income companies
- Using the wrong form type (ET1 vs ET3) for the company category
- Missing the deadline because the accounting year end is not 31 December and the 6-month rule catches filers off guard
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