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Does a CIO need to file a Company Tax Return?

Last updated: 3 October 2026

Short version. A charitable incorporated organisation (CIO) must deliver a Company Tax Return when HMRC issues a notice to file, even if no Corporation Tax is payable. It uses CT600 and, when claiming charity exemption, CT600E. It does not need a Companies House number.

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1. Why a CIO uses CT600

A CIO in England and Wales is a body corporate under Charities Act 2011 section 205. Corporation Tax law treats a body corporate as a company. That does not make it a Companies Act company. A CIO is registered with the Charity Commission, not Companies House.

HMRC places charities other than trusts within Corporation Tax Self Assessment. A charitable trust uses Self Assessment instead. Do not send a CIO’s return as SA900 merely because it is a charity. Nor should you ignore a notice to file because the charity expects full exemption.

The return to HMRC is separate from the annual accounts and return due to the Charity Commission. Common mistakes include putting the charity number in CT600 box 2, searching for a Companies House record that does not exist and assuming a charity’s tax return is a Gift Aid repayment claim. See the CIO and charitable company comparison.

2. Prepare and check the return

Use the charity’s Corporation Tax UTR in CT600 box 3. CT600 box 4 is code 8 for a charity. CT600E box E5 is the HMRC repayment reference. E10 is the Charity Commission or OSCR number, if applicable. Do not confuse either number with the UTR or enter a charity number as a Companies House number.

A full-exemption claim uses E15 and E20 on each return. All income and gains must be exempt and have been, or be intended to be, applied for charitable purposes. Spending money on charitable purposes alone does not establish that the income is exempt. A partly taxable charity uses different treatment and is outside this service’s charity route.

HMRC Chapter 6 paragraph 6.9.7 permits PDF or iXBRL accounts from unincorporated associations and incorporated charities not required to prepare accounts under the Companies Act or Friendly and Industrial and Provident Societies Act 1968. That includes CIOs and SCIOs. This permission has no income threshold. It is separate from the £6.5 million smaller Companies Act charity concession. Annual accounts normally accompany the return. Giving a reason for omission does not remove that obligation.

Under paragraph 6.9.9, a wholly exempt CT600E return needs no tax computation. The supported filing includes an explanation PDF instead. An accounts period over 12 months and up to 18 months produces two CT600 and CT600E returns. Enter full-period recurring figures once, use the visible allocation controls for amounts assigned to a return and check both previews and receipts. The same supplied accounts accompany both.

The proper officer of a body corporate is normally the secretary or acting secretary. If there is none, the treasurer or acting treasurer is the proper officer. Another person with the organisation’s authority can also act, except where a liquidator has been appointed. A liquidator or administrator is the proper officer when appointed. Enter the capacity in which the authorised person actually signs.

For example, a fictional charity that has established full exemption has £10,000 of donations and £8,000 of charitable spending. It enters the prepared CT600E disclosures rather than treating the £2,000 surplus as automatically taxable or automatically exempt. Its full-exemption claim produces nil Corporation Tax. For a long period, review the figures attributed to each accounting period.

A Company Tax Return is normally due 12 months after the accounting period ends. A late notice to file can extend that deadline, so read the notice and check each return’s filing date. For filing dates on or after 1 April 2026, the fixed penalty is £200 when late and another £200 after three months. Earlier filing dates use the previous amounts. Repeated late filing and tax-related penalties have separate rules. A charity can incur a late-filing penalty even when no tax is due.

SimpleCompanyTax files wholly exempt CIO and SCIO returns without a Companies House number. Follow the CIO and SCIO filing steps and related FAQs. We do not prepare charity accounts, decide entitlement to exemption or submit Charity Commission or OSCR filings.

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