Corporate Income Tax 2026: what your company must know before filing

The Corporate Income Tax season for the 2025 financial year begins in July 2026 for companies whose tax period matches the calendar year. The ordinary deadline to file Form 200 is twenty-five calendar days counted from the six months following the close of the financial year —that is, until 25 July for those closing on 31 December. These are the most relevant points of the season.

Tax rates in force for 2025

The general Corporate Income Tax rate remains at 25% (Article 29 of the Corporate Income Tax Act, Law 27/2014). Alongside it, several reduced rates of real relevance to Murcia's SMEs apply:

• 23%: for entities whose turnover in the previous tax period was below €1,000,000. This rate, introduced to ease the burden on micro-enterprises, applies to a significant share of the business fabric of the Region of Murcia.
• 15%: for newly created entities during the first two tax periods in which they obtain a positive taxable base. A newly created entity is one that does not continue a previously conducted activity and does not form part of a group with another company.

Negative taxable bases (loss carryforwards): offset limit

Negative taxable bases generated in earlier years may be carried forward without any time limit (Article 26 of the Act). However, the amount that can be offset each year is capped at 70% of the taxable base prior to the offset for entities with a net turnover equal to or above €20 million in the preceding twelve months. For smaller entities, the limit is 70%, with a minimum of €1 million offsettable in any case.

The global minimum tax (Pillar Two)

The most significant milestone for large corporate groups is the entry into force of the 15% minimum effective rate for large multinational and domestic groups, in line with Directive (EU) 2022/2523, which transposes the OECD/G20 Agreement on the second pillar (Pillar Two). This measure ensures that the profits of large companies operating across multiple countries are taxed at a minimum effective rate of 15% in each jurisdiction.

For SMEs and mid-sized companies not belonging to a large group, Pillar Two has no direct effect —its scope requires the group to exceed €750 million in consolidated revenue. It does, however, affect them indirectly through their value chain when their clients or suppliers are groups subject to the new rule.

The R&D&I deduction: the most powerful incentive in the tax

The deduction for research, development and technological innovation (Article 35 of the Act) remains the most powerful tax incentive in Corporate Income Tax for companies that invest in innovation:

• R&D: a 25% deduction on the year's expenditure. Where that expenditure exceeds the average of the two previous years, the excess attracts a 42% rate.
• Technological innovation: a 12% deduction on innovation expenditure —obtaining patents, industrial design, acquisition of non-patented technology.
• Unused deductions may be carried forward to the following 18 years.
• In certain cases, the deduction may be claimed as a cash payment to the company (refund) where it exceeds the gross tax liability, capped at €3 million per year for R&D and €1 million for technological innovation.

To apply it correctly, the project must be properly documented and, in higher-value cases, supported by a binding reasoned report from the Ministry of Science and Innovation, which provides legal certainty before the Spanish Tax Agency.

Capitalisation reserve: an incentive to self-financing

The capitalisation reserve (Article 25 of the Act) allows the taxable base to be reduced by 10% of the increase in equity for the year, provided that amount remains undistributable for five years. It is the instrument designed to encourage companies to retain profits and strengthen their financial structure rather than distribute them. For SMEs with recurring profits seeking to grow without debt, it is one of the most accessible tax-optimisation tools.

Levelling reserve: SMEs only

Small-sized entities (turnover below €10 million) may apply the levelling reserve (Article 105 of the Act): a reduction of up to 10% of the positive taxable base to fund a reserve that will offset future negative bases or, if no loss arises in the following five years, will be added back to the taxable base as deferred income. It is, in essence, a free deferral of the tax.

Taxation of dividends: the participation exemption

Income from holdings in the capital of other entities —dividends and capital gains on the transfer of holdings— is 95% exempt where the requirements of Article 21 of the Act are met: a direct or indirect holding of at least 5% of the capital or voting rights, held uninterruptedly for the preceding year. The remaining 5% is taxed as ordinary income, implying an effective rate of 1.25% on the dividend received for entities taxed at the general rate.

How we help with Corporate Income Tax at RCM Legal

Filing Corporate Income Tax is not a mechanical exercise. There are recurring sources of error that, if detected before 25 July, can be corrected without consequence: deductions from prior years that are not carried forward, expenses wrongly classed as non-deductible, impairment adjustments on investments not properly applied, and differences between the accounting result and the taxable base that are not duly reconciled. A technical review before filing not only reduces risk: it often reveals optimisation opportunities the company was unaware of.

At RCM Legal we prepare and file Form 200, apply every applicable deduction and allowance —R&D&I, capitalisation reserve, levelling reserve, loss carryforwards— and advise on tax planning for the 2026 financial year with the aim of optimising the tax burden lawfully and on a documented basis. If you receive a proposed assessment or are notified of the opening of a tax audit, we represent and defend you at every stage. Talk to us.