Form CT1 Company Tax Return in Gibraltar | Explained

Tax Filing in Gibraltar: The Form CT1 Company Tax Return ExplainedCopy link to section

Tax filing in Gibraltar means submitting Form CT1 – Company Tax Return to the Income Tax Office for each accounting period. The obligation rests on the Income Tax Act 2010 and applies broadly: every company registered with Companies House Gibraltar, and every foreign company with income arising in the territory, must file, whether or not any tax is due. Guidance for the form is published by the Income Tax Office, which administers assessment and collection through the Commissioner of Income Tax.

This article sets out who must file, what the return contains, the deadlines and payment rules, how submissions are made, and the penalties for getting it wrong. It is written for non-resident owners of companies tied to Gibraltar and for the advisers who manage their compliance from abroad.

Which Companies Must File a Form CT1 in GibraltarCopy link to section

The filing trigger is registration, not profit. Since 1 January 2016, any company on the register at Companies House Gibraltar must file a Form CT1 each year, as must any company with assessable income arising in the territory under the Income Tax Act 2010.

There is no de minimis exemption for registered companies. A firm that made no profit, holds no Gibraltar-source income, or conducts all its trade abroad still owes a return.

For a non-resident owner, this point matters most. If your company was set up under the Companies Act 2014, the duty to file follows from incorporation alone, regardless of where the business actually operates.

A company that stops trading does not stop filing. It must confirm the ceased-trading date to the Income Tax Office in writing and continue submitting complete returns until liquidation completes or the registry strikes the company off.

The standard corporation tax rate is 15%, effective 1 July 2024 (raised from 12.5%). Utility businesses and companies with a dominant market position, including electricity, fuel, water, and telephony, are charged at 20%.

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Registering for Tax with the Commissioner of Income TaxCopy link to section

Registration for tax is automatic. When a company is entered on the register at Companies House Gibraltar, it is registered for corporate tax at the same time; no separate application to the Income Tax Office is needed.

A Tax Identification Number (TIN) is issued on registration. If you cannot locate your TIN, request it directly from the Income Tax Office rather than re-registering.

The return must be filed by a statutory officer, a shareholder, or a person authorised to act. Where an agent submits on the company's behalf, the office requires written confirmation of that authority.

Agent authorisation follows a set route: a letter to the Commissioner of Income Tax, carrying an original signature, lodged with the office. Guidance Note CT101 (Form CT3A) covers the process. Without that letter on file, an agent's submission is not valid.

What Must Be Reported on the Form CT1Copy link to section

Form CT1 is an Excel spreadsheet downloaded from the official site. It captures the company's identifying details and tax computation, and it must travel with financial statements showing income and expenses.

A complete Company Tax Return is more than the spreadsheet. It includes every compulsory element named in the guidance: signed accounts, the tax computation, and, where relevant, a PAYE reconciliation. Omitting any required annexure makes the return incomplete, with the same consequences as not filing at all.

The information the return must disclose is straightforward in substance:

• Company identification data: TIN, registered address, and accounting-period dates
• Gross income and allowable deductions
• Taxable profit or loss, with the tax computed at the applicable rate
• A PAYE reconciliation where the company had employees and its year-end is not 30 June
• A signed declaration by an authorised officer

The form of accounts you attach depends on size. Where assessable income exceeds £1.75 million, audited accounts are required. Below that figure, an Independent Accountant's Report may accompany the accounts instead. The threshold rose from £1.5 million to £1.75 million on 1 July 2024.

Size classification under the Companies Act 2014 also matters. A company treated as "small" avoids full audited accounts; that status depends on meeting two of three criteria over two consecutive years, one of which is net turnover below £10.2 million, with balance-sheet and headcount tests set out in Schedule 9 of that Act.

Form CT1 goes to the Income Tax Office, not to Companies House. It sits separately from the annual accounts filed with the registry, which is its own obligation.

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The Filing Deadline and Frequency for the Company Tax ReturnCopy link to section

One return covers one accounting period, filed annually. The deadline is nine months after the end of the month in which the accounting period closes, under Section 29 of the Income Tax Act 2010.

A worked example makes the timing clear. A company with a 31 December year-end must file Form CT1 by 30 September of the following year.

Gibraltar taxes companies on a current-year basis, assessed against their own accounting periods. No formal extension procedure is published in official guidance, so the nine-month date should be treated as fixed.

One sequencing point catches out many foreign owners. The tax return is due at nine months, but the accounts filing at Companies House is due at thirteen months; the tax deadline comes first, and your compliance calendar should reflect that order.

Paying Tax Due and Payments on AccountCopy link to section

Payment and filing share the same deadline. When you submit the return, you must also settle the balance of any tax owed after crediting payments already made during the year.

Payments on Account (POAs) are advance instalments based on the prior year's liability, governed by Schedule 10 of the Income Tax Act 2010. They fall due in two equal parts, by 28 February and 30 September, set against the company's financial period.

If taxable profits for the period exceed the two POAs combined, a balancing payment is due. That additional amount is payable within the same nine-month window as the return.

A company that expects a lower liability than the previous year may apply to reduce its POAs using Form CT4. The form cannot be lodged for a period that has already ended, and surcharges apply if the eventual liability exceeds the reduced instalments.

Surcharges run independently of any late-filing penalty, and legal action may begin at any time after the first default. Payments, including POAs and CT1 assessments, are made through the Income Tax Office portal at tax.egov.gi.

Note one enforcement power. The Commissioner may publish in the Gibraltar Gazette the details of any taxpayer who owes at least £5,000 that has been unpaid for three months past the due date, after giving 30 days' notice of intent to publish.

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How to File the Form CT1: Portal and Submission ProcessCopy link to section

There is no online e-filing portal for the return itself. Form CT1 is an Excel file downloaded from the Income Tax Office downloads page, completed offline, and returned by email.

Two email addresses apply, depending on the period:

• Chargeable-period returns to CT1C@gibraltar.gov.gi
• Non-chargeable-period returns to CT1N@gibraltar.gov.gi

Tax payments are handled separately through tax.egov.gi. As a Gibraltar company you therefore deal with two distinct government channels: the Companies House e-Registry for annual returns, accounts, and director changes, and the Income Tax Office for the corporation tax side. Filing the annual return at the registry does not discharge the Form CT1 duty.

The system runs on self-assessment, but the office retains a check. It may open an enquiry into a return within 12 months of the filing due date, or, where the return was filed late, within 12 months of the date it actually arrived.

Penalties for Late or Incorrect FilingCopy link to section

Penalties attach where a complete return is not submitted on time, and the regime changed at the start of 2025. From 1 January 2025, late-filing penalties are scaled to company size as defined in Schedule 9 of the Companies Act 2014, under the Income Tax (Amendment No.3) Act 2024.

For large companies, the late-filing penalty can reach up to £5,000 where the return is more than six months late. Small companies fall into a lower tier; the exact amounts at each trigger point are set out in the Income Tax Office corporate guidance and should be confirmed there before relying on a figure.

The earlier regime, in force until the end of 2024, charged £50 for a late return, with a further £300 once more than three months late and an additional £500 beyond six months. Those figures remain useful only as historical reference.

Other penalties operate alongside the late-filing scale:

• Failing to respond to a notice or information request draws a £200 fine on the day of failure, rising by £1,000 if it continues a month past the relevant date; non-compliance beyond three months can, on conviction, lead to imprisonment.
• An incorrect return delivered fraudulently, recklessly, or negligently can attract a fine of up to 150% of the tax understated.
• Failing to notify the Commissioner of a tax-avoidance arrangement carries the same £200, then £1,000, structure as the notice penalty.

The statutory hooks are Section 65 for failure to file or to meet the return's requirements, and Section 66 for false returns. An incomplete return, missing a compulsory element, is treated as a failure under Section 65.

Legal Basis: The Income Tax Act 2010 and the 2024 AmendmentCopy link to section

The governing statute is the Income Tax Act 2010.pdf) (Act No. 2010-21), as amended, administered by the Commissioner of Income Tax. Several provisions carry the weight of the filing obligation.

• Section 29 sets the duty on every company to make a full and complete return and fixes the nine-month deadline.
• Section 65 governs penalties for failing to file or to meet the return's requirements.
• Section 66 addresses incorrect returns delivered fraudulently, recklessly, or negligently.
• Schedule 10 governs Payments on Account and their timing.
• Section 11 and Schedule 1 define what income is assessable, applying a source-based, territorial test for companies.

The 2024 amendment reshaped the penalty side. The Income Tax (Amendment No.3) Act 2024 (No.21 of 2024) passed into law on 23 December 2024 and took effect on 1 January 2025, tying late-filing penalties to the company-size definitions in Schedule 9 of the Companies Act 2014.

One further measure sits beside, not within, the Form CT1 regime. The Global Minimum Tax Act 2024, enacted on the same date, introduced a Domestic Top-up Tax and an Income Inclusion Rule aligned with the OECD GloBE Model Rules; it reaches only qualifying large multinational groups and is separate from the ordinary company return.

Common Filing Mistakes and How to Stay CompliantCopy link to section

Most failures come from treating Form CT1 as a single document. The return is the spreadsheet plus all compulsory annexures, and a missing element invalidates the whole submission.

Watch the accounts format in particular. Filing unaudited accounts where assessable income exceeds £1.75 million makes the return incomplete, even if every figure is correct.

Several other errors recur among foreign-owned entities:

• Assuming no Gibraltar-source income removes the duty to file; it does not, and the office may ask for supporting evidence.
• Waiting for the Commissioner to issue a return; the obligation is proactive and exists whether or not a return is sent to you.
• Confusing the two deadlines; the tax return is due at nine months, the Companies House accounts at thirteen.
• Letting an agent submit without a signed authority letter on file, which renders the submission invalid.
• Underpaying POAs after a CT4 reduction, then incurring surcharges when the actual liability turns out higher.

Record retention deserves a note of honesty. Official Gibraltar guidance for corporate tax records does not state a fixed retention period; the confirmed reference point is the 12-month enquiry window from the filing date, and practitioners commonly keep records for six years in line with general standards.

ConclusionCopy link to section

Filing Form CT1 turns on registration, not on whether your company earns or profits in the territory. If the firm sits on the Gibraltar register, a full and complete return is due nine months after the accounting period closes, with the tax payable on the same day, and the cost of a late or incomplete submission has risen under the 2025 penalty regime.

The practical priority for a non-resident owner is sequencing: map the nine-month tax deadline, the two POA dates, and the separate thirteen-month accounts filing onto a single calendar, and confirm whether your assessable income crosses the £1.75 million audit line before you choose the accounts you attach.

How Expanship Can Help Your Business in GibraltarCopy link to section

Expanship prepares and submits Form CT1 returns on behalf of foreign-owned companies, handling the tax computation, the supporting accounts, POA scheduling, and the agent-authorisation letter the Income Tax Office requires. The same team supports the wider compliance load that a non-resident owner carries across the territory.

• Company formation under the Companies Act 2014
• Registered agent and registered office services
• Ongoing compliance and management of filing deadlines
• Accounting and bookkeeping, including audit-threshold assessment
• Economic-substance and beneficial-ownership support
• Introductions to banking providers

To discuss your company's filing position, contact Expanship Gibraltar.

Frequently Asked QuestionsCopy link to section