Legal tax optimisation is not a practice reserved for large corporations. Spanish SMEs have access to a set of legally established mechanisms under the Corporate Income Tax Act that can significantly reduce the tax burden. The problem is rarely a lack of tools — it is a lack of planning. Most of these mechanisms require decisions before the year-end close, not afterwards.
The starting point: understanding the taxable base
The tax liability under Corporate Income Tax is calculated by applying the applicable rate to the taxable base. But the taxable base is not accounting profit: it is the result of adjusting that profit with the corrections established by tax law (permanent and temporary differences). Optimising corporate tax begins with understanding those differences and acting on them before the financial year closes.
Mechanisms for reducing the taxable base
Capitalisation reserve
The capitalisation reserve is one of the most efficient incentives for companies that generate profits and can reinvest them. It allows a reduction of the taxable base equal to 10% of the net increase in equity, with the requirement to allocate an undistributable reserve for five years. For a company with a net equity increase of €200,000, the reduction is €20,000, which translates into a tax saving of up to €5,000 at the standard 25% rate.
Accelerated tax depreciation
The rules allow reduced-dimension companies (net turnover below €10 million) to depreciate new assets freely up to an amount equal to the profit multiplied by the applicable update coefficient. In addition, the depreciation tables allow coefficients above the minimum accounting rate, accelerating the timing of the deduction.
Carry-forward of tax losses
Tax losses from prior years can be offset indefinitely against future taxable profits (subject to the 70% annual quantitative limit for taxable bases above €1 million). If your company incurred losses in prior years and is now profitable, ensure those losses are correctly recorded and being applied.
Double taxation relief
When a parent company receives dividends from subsidiaries, the exemption regime prevents double taxation on income already taxed at the subsidiary level. Correct application of this mechanism in corporate groups can virtually eliminate taxation on intra-group dividends.
Tax incentives that SMEs frequently fail to apply
R&D&i deduction
Research and development and technological innovation activities generate deductions against the Corporate Income Tax liability that can be material. Many SMEs carry out R&D activities without recognising them as such: bespoke software development, production process improvements, new product development. The first step is to correctly classify the activities and document them adequately.
Free depreciation for job creation
Companies that invest in new assets and create net employment can depreciate those assets freely. The limit is €120,000 multiplied by the net increase in full-time equivalent headcount.
Deduction for investment in film and performing arts productions
Companies that invest in audiovisual or theatrical productions can access deductions of between 20% and 54% of the investment. This deduction is particularly attractive for companies with high tax liabilities seeking alternative investments with a tax impact.
Equalisation reserve (levelling reserve)
Available exclusively to SMEs (reduced-dimension entities), the equalisation reserve allows a reduction of up to 10% of the taxable base (up to a maximum of €1 million) for future loss offset purposes. The reserve must be allocated for five years, but if a loss occurs, it can be set off immediately.
Year-end tax planning: the key moment
Most optimisation mechanisms require decisions before 31 December: allocating the capitalisation reserve, making the investments that generate accelerated depreciation, deciding on the level of dividend distribution. Year-end tax planning in the last quarter is the most valuable moment of the fiscal year for an SME.
A well-executed close analysis should include:
- Projection of the year’s taxable base
- Review of assets with remaining book value and available tax loss carry-forwards
- Identification of investments that could be made before year-end with an impact on Corporate Income Tax
- Decision on dividend distribution and reserve allocations
- Verification that all deductions generated in prior years are being applied
Common planning mistakes
Leaving it until January. Most decisions — reserve allocations, investment timing, dividend calls — must be taken before 31 December. A review in January can identify what was left on the table, but cannot recover it.
Treating deductions as uncertain. Many SMEs fail to claim R&D deductions because they assume the activity does not qualify or because they fear audit scrutiny. Obtaining a binding opinion from the Ministry of Science before claiming removes uncertainty and protects the deduction.
Not reviewing loss carry-forwards. Companies that went through difficult periods — particularly 2020–2021 — may hold substantial tax losses that they are not actively applying. A systematic review with a tax adviser can reveal carry-forwards that materially reduce the current year’s liability.
Ignoring the capitalisation reserve. This is one of the most universally applicable mechanisms for profitable SMEs and one of the most frequently unused. The decision to allocate the reserve must be taken before year-end and reflected in the accounting.
How BMC can help
Our tax planning team conducts a year-end tax review for companies every fourth quarter, identifying all applicable mechanisms for each client’s specific situation. The service includes the preparation and filing of the Corporate Income Tax return with all optimisation fully documented and defensible before the AEAT.
If your company carries out R&D or innovation activities, our R&D tax incentives specialists can identify and document the applicable deductions, maximising the tax return on your innovation investments.
