Business expenses and Corporation Tax

An accounting expense is not automatically deductible for Corporation Tax. Review whether the cost is revenue or capital, its business purpose and any specific restriction. HMRC identifies client entertaining as an example of a disallowed expense and explains that some categories follow separate rules.

Keep a clear explanation and evidence for mixed or unusual costs. Where a business element can be separately identified, its treatment needs assessment rather than an arbitrary percentage. Capital expenditure may require a relief review instead of deduction as an ordinary running cost.

Identify the substance and business purpose

Ask what the company bought, why it incurred the cost and what benefit or asset resulted. A ledger code called business expense does not establish deductibility. HMRC's guidance distinguishes capital and revenue expenditure, business purpose and specific disallowances. ^[1] Review the actual transaction with supporting documents rather than treating every cost paid by the company as an automatic reduction in taxable profit.

Keep the relevant contract, invoice and a factual explanation. For professional fees, identify the matter they concern; fees for acquiring a long-term asset can raise different questions from routine administration. For mixed invoices, separate components where the evidence supports it. Do not assume all payments to the same supplier have the same tax treatment simply because previous invoices were deductible.

Distinguish capital costs and restricted categories

A payment acquiring or improving an enduring asset may need capital treatment and a separate relief review. Accounting depreciation is not itself the tax deduction. Use Capital expenditure and tax treatment to collect the information needed for capital allowances or other applicable treatment. Avoid deciding the tax result solely from the size of the payment or the bookkeeping system's default category.

Review specifically restricted expenditure, including client entertaining where relevant. The fact that hospitality helped win work does not remove the need to apply the tax rules. Keep the accounting entry accurate and make the appropriate tax adjustment rather than deleting the cost from the accounts. Use Tax treatment of company entertaining for entertaining and separate Corporation Tax from VAT or employment-benefit questions.

Analyse mixed and unusual costs with evidence

Where a cost has both business and another purpose, describe the facts and any separately identifiable components. An arbitrary percentage is not a substitute for an appropriate analysis. Ask the accountant whether a supported business element can be treated separately under the applicable rules. Keep the reasoning and evidence so a later reviewer can understand the conclusion.

Identify connected-party payments and unusual remuneration, rent or service arrangements. The relationship and commercial terms can matter. Do not assume a payment is deductible simply because the recipient issues an invoice or is also a director. Supply agreements, work evidence and the basis of the amount, with specialist input where the arrangement raises technical questions beyond routine expense coding.

Keep timing and tax adjustments traceable

Confirm the relevant period and whether any special timing rule applies. Payment, accrual and deduction do not always coincide. Preserve the accounting-to-tax bridge showing additions and deductions with references to evidence. A spreadsheet adjustment should state the reason rather than contain an unexplained round number chosen to arrive at an expected liability.

Review consistency with previous periods while remaining alert to changed facts. A cost previously treated one way may need a different analysis after the company's activity or the arrangement changes. If an error is found in an earlier return, ask about the appropriate correction route rather than silently compensating through the current computation without a basis.

For Company tax planning review, provide the uncertain expenditure list, supporting documents and business explanations. Ask for decisions on classification, restrictions and timing with any further evidence required. Keep the result with the tax file and improve bookkeeping categories where recurring costs need separate identification. This allows the company to claim appropriate deductions while retaining an honest record of costs that belong in the accounts but receive different treatment for Corporation Tax.

Review a transaction with several cost elements

A single supplier invoice may include equipment, training, maintenance and financing charges. Obtain a breakdown and identify what the company actually received before assigning the whole amount to one tax category. The supplier's headline description or the bookkeeping account chosen at entry is only a starting point.

Keep the allocation evidence and the accountant's treatment with the invoice. If the supplier cannot provide a useful breakdown, record that limitation and the basis of any further assessment. Reconcile the accounting entries and tax adjustments so an item is not omitted or deducted twice. This approach is particularly helpful for bundled contracts, where a convenient single payment can conceal several elements with different timing or treatment under the applicable rules.

Illustrative scenario

A company pays for both routine maintenance and an improvement to an asset under one supplier invoice. The accountant asks for a breakdown and the underlying work description. The treatment follows the facts of each element rather than coding the entire invoice to repairs because that is the easiest ledger category.

Preparation checklist

• Identify what the company obtained and why.
• Separate capital, revenue and personal elements.
• Check specific restrictions and applicable reliefs.
• Keep the tax adjustment linked to the ledger and evidence.