How to file a CT600 for an investment company

In short: File an investment company's CT600 with its accounts and tax computation, separating investment income, management expenses and chargeable gains. A close investment-holding company pays the 25% main rate. Taxley prepares and files the return for £139 with small-company accounts, using the Advanced editor when you choose “Holds investments”.

Take the 30-second check to see whether Taxley fits your company.

Key facts (checked on 16 October 2026)

What counts as an investment company for this return?

An investment company here holds investments without carrying on a trade or letting property. It may hold shares, funds, bonds, Bitcoin or cash, receive income and pay running costs. Its lack of sales does not remove the need to report taxable income or gains on a Company Tax Return.

Choose the business type that describes the company's actual activities. A company with rent belongs on the property route. Buying and selling assets as a trade is different from holding them as investments. This guide deals with the company whose business is holding investments, with no trade and no letting.

Does every investment company pay Corporation Tax at 25%?

A close investment-holding company, or CIHC, pays the 25% main rate on all taxable profits. It cannot use the small profits rate or marginal relief, even when profits are below £50,000. Investment company status alone does not establish that it is close, so check the company's ownership and purpose.

A close company is broadly controlled by five or fewer participators, or by participators who are directors. Permitted purposes can keep a close company outside CIHC status, including commercial trading, commercial letting to unconnected tenants and certain holdings in controlled companies. A family company mainly holding listed shares or cash will usually be a CIHC.

Our Corporation Tax rates and marginal relief guide explains the rate rules. The small-company test for dividend exemption is separate: paying the CIHC main rate does not automatically make dividends received taxable.

Where do interest, dividends and fund income go?

Bank interest and net non-trading loan relationship profits go in box 170. Non-exempt overseas company distributions go in box 180. Exempt dividends stay outside taxable profits, with qualifying non-group actual distributions reported in box 620. Offshore funds need separate checks for legal form, tax residence, reporting status and bond-fund treatment.

Start with the company bank interest guide and dividends received guide. Do not treat every payment described as a dividend on a broker statement as exempt.

An Irish or Luxembourg corporate fund needs the payer's tax-residence conditions checked. Taxley treats its distributions as taxable unless the customer confirms the exemption conditions with fund-specific evidence. Excess reportable income can also be taxable without a cash payment. A fund holding more than 60% debt-type qualifying investments at any time in the period uses the loan relationship rules and fair value treatment.

The Irish ETF dividends guide has a decision table. A gain on disposing of a non-reporting offshore fund is generally an offshore income gain in box 205. Reporting-fund disposals follow the chargeable gains route.

How are management expenses and Bitcoin treated?

Qualifying management expenses reduce total profits in box 245, with current expenses deducted before other Step 2 deductions. Unused current expenses go in box 850 and may be carried forward. Bitcoin simply held as an investment follows chargeable gains rules, so an accounts impairment does not create an immediate tax deduction.

Keep recurring management costs separate from capital dealing costs, interest, depreciation and investment write-downs. The management expenses guide explains the two-year claim deadline for using a carried-forward excess.

For held Bitcoin, remove an impairment from deductible costs and work out the tax gain or loss on disposal using the relevant tax cost. Our Bitcoin guide distinguishes holding tokens from using them on a continuing basis. The company chargeable gains guide explains boxes 210, 215 and 220.

What does a full investment company CT600 example look like?

A CIHC with £6,000 of bank interest, £3,800 of taxable corporate fund income and £4,000 of chargeable gains has £13,800 before management expenses. Deduct £2,200 of qualifying expenses to leave £11,600 taxable profits. At 25%, Corporation Tax is £2,900, with no marginal relief.

Illustrative assumptions: a 12-month period ending 31 January 2026; no trade or letting; no foreign tax, capital losses, other reliefs, tax paid or outstanding liabilities affecting the calculation. The corporate equity fund is not a bond fund. Its £3,000 distribution and £800 excess reportable income are taxable because exemption has not been established. The £4,000 gain is already worked out for tax.

The accounts also contain a £10,000 impairment of Bitcoin held as an investment. It is excluded from management expenses and gives no deduction in this return. There is no Bitcoin disposal. All figures below are illustrative, rather than a completed return for a real company.

This walks through the boxes relevant to these facts; company details, declarations and the financial-year tax calculation must also be completed. For comparison, if qualifying current management expenses were £15,000, box 245 would be £13,800, box 850 £1,200 and taxable profits nil. That excess belongs in the carry-forward records, with a claim needed when used later.

Which accounts and deadlines apply?

Taxley uses small-company accounts under FRS 102 Section 1A for investment companies and does not offer micro accounts for this route. For a normal subsequent year, Companies House accounts are due nine months after year end. Corporation Tax is normally payable nine months and one day after the period ends; the CT600 follows at twelve months.

For the example year ending 31 January 2026, the normal accounts deadline is 31 October 2026, tax payment is due 1 November 2026 and the CT600 is due 31 January 2027. First accounts and companies paying tax by instalments need separate deadline checks. Use the Corporation Tax deadline calculator and deadline guide.

How do you file the investment company return with Taxley?

Choose “Holds investments” when starting the return, then prepare it in the Advanced editor. Enter the investment income, running costs, balance sheet and investment details. Taxley works out the relevant tax boxes and prepares the CT600, accounts and computation for review before filing. The small-company accounts fee is £139.

1. Confirm the company details, period and CIHC answer.
2. Enter interest, dividends, fund details and any excess reportable income.
3. Enter running costs and identify costs that cannot be claimed.
4. Record crypto treatment and any disposals without duplicating fund income gains.
5. Complete the small-company accounts, policies and investment notes.
6. Review the computation, tax bill and carry-forward balances, then finish and file the return.

Taxley files the generated accounts at Companies House once the return is paid and finished. Uploaded accounts follow a separate filing route. Paying for the return does not pay the Corporation Tax bill: make that payment to HMRC by its deadline. Check your company's fit before starting.

Frequently asked questions

Can a company with no sales still owe Corporation Tax?

Yes. Bank interest, taxable fund income and realised investment gains can create taxable profits without sales. A company holding investments should classify each receipt and disposal before deducting qualifying management expenses.

Is a small investment balance enough to get the 19% rate?

No. A close investment-holding company pays the main rate regardless of how little it earns. The size of its portfolio does not restore the small profits rate or marginal relief.

Does an exempt dividend cover the company's tax bill?

An exempt dividend is left out of taxable profits. It does not exempt bank interest, taxable fund income or chargeable gains. The treatment of each income source must be checked separately.

Can I claim the whole portfolio write-down as running costs?

No. An investment write-down is not a management expense. For Bitcoin simply held as an investment, the accounts impairment gives no immediate deduction; the tax gain or loss is worked out on disposal.

General information, not personalised tax or accounting advice.