Identifying tax-deductible expenses for Spanish Corporate Income Tax requires a review of the actual transaction, its accounting treatment and the applicable tax rules. An invoice is important, but it is not enough to conclude that every amount reduces the taxable base.
For a finance team, the aim is to be able to explain every material expense: what the company received, why it needed it, which financial year it relates to and what evidence supports it.
What the company should check
As a general rule, deductibility requires appropriate accounting recognition, supporting evidence and allocation to the correct period, together with an assessment of its connection to the business and any statutory limits or exclusions. Exceptions and special rules exist, so a general checklist does not replace a review of each expense category.
- Substance: there must be a genuine transaction, not just a document or accounting entry.
- Evidence: the documentation should identify the service or supply and its recipient.
- Recording: compare the invoice with the ledger account and the relevant financial year.
- Tax treatment: check whether an exclusion, limit or specific rule applies.
Expenses that deserve particular attention
Client hospitality, finance costs, impairment, directors’ remuneration and services between related entities should not be treated using an automatic rule. Their analysis may require contracts, corporate resolutions, calculations or additional evidence.
Article 15 of the Spanish Corporate Income Tax Law lists non-deductible expenses, including criminal and administrative fines and penalties. The requirement to record an item in the accounts does not mean it must be accepted for tax purposes: an adjustment in the tax return may be necessary.
Why an invoice may not be enough
Imagine a significant invoice described only as “consultancy services”. To explain the transaction, the company should be able to connect it with the engagement, the work delivered and how it was used. A contract, report or acceptance of the service can provide context and traceability.
This example does not mean that one set of documents is suitable for every case. The evidence needed depends on the nature of the transaction and what must be demonstrated. It is advisable to organise it when the expense is incurred, rather than waiting for a tax review.
Four common internal control errors
- Equating payment with accrual: the payment date does not, by itself, determine the tax period of an expense.
- Confusing Corporate Income Tax and VAT: expense deductibility and input VAT recovery have their own rules.
- Using generic descriptions: vague wording makes it harder to identify the transaction and review its treatment.
- Repeating last year’s approach: the transaction, requirements or applicable interpretation may have changed.
How to organise an expense file
A useful internal policy defines who authorises an expense, what information must accompany it and which situations need tax review. For higher-risk items, keep a record of the supplier, purpose, contract, evidence of delivery, accounting entry and tax conclusion.
At year-end, the finance department can use this classification to separate ordinary expenses from those requiring specific analysis. This makes it easier to justify adjustments and maintain a consistent approach across group companies.
Is every expense necessary for the business deductible? Not necessarily: tax exclusions and limitations must also be considered.
Can an expense from another year be deducted? This requires analysis of the rules on timing; the date the invoice was received should not be the only consideration.
A tax review supported by documentation
Adeltra’s tax advisory team helps review transactions and coordinate their treatment with accounting. Contact our team if you need to review your company’s expenses before year-end.
Legal source: Law 27/2014 on Spanish Corporate Income Tax, including Articles 11, 15, 16 and 18. General information reviewed in October 2026.