Polish taxpayer questions whether R&D tax credit can reduce solidarity surcharge base beyond 1 million PLN threshold.
What is the Solidarity Surcharge?
The 4% solidarity surcharge is paid by PIT taxpayers on income exceeding 1 million PLN in total income. According to Article 30h, section 2 of the PIT Act, this applies to incomes: taxed according to the tax scale, e.g., from work, business activity, pensions, retirement benefits, personally performed activities, copyrights; from capital gains, i.e., from the sale of shares, stocks, derivative financial instruments; from business activity taxed at a flat rate; from a foreign controlled foreign company (CFC).
Calculating the Surcharge Base
There have been longstanding doubts about calculating the base for the solidarity surcharge. A few years ago, the tax authority claimed that taxpayers could not deduct losses. In this matter, in favor of taxpayers, the Supreme Administrative Court ruled in judgments of: May 6, 2025 (ref. no. II FSK 1007/22), February 14, 2023 (II FSK 1099/22), December 13, 2022 (II FSK 1072/22), December 7, 2022 (II FSK 1172/22), July 19, 2022 (II FSK 452/22).
Essentially, the tax authority now allows for the inclusion of losses from previous years. This is confirmed by the changing interpretation of the head of the National Revenue Administration from September 24, 2024 (DOP3.8220.5.2024.HTCE). However, it claims that they must relate to income generated from a specific source of revenue (see interpretation of November 18, 2025; 0113-KDIPT2-3.4011.692.2025.2.PR).
R&D Tax Credit and the Surcharge
A man, a partner in a general partnership, asked about tax credits. He receives income from conducted business activity taxed at a flat rate (19%). He explained that he uses the research and development (R&D) tax credit. He wanted to ensure that qualifying costs reduce not only the PIT tax base but also the basis for calculating the solidarity surcharge.
He argued that the regulations concerning the solidarity surcharge (Article 30h, section 2 of the Act) use the term “income subject to taxation” and not just “income”. Since in the annual tax return, income tax is calculated from the amount of revenue reduced by the costs of obtaining revenue, including qualifying costs, loss from the previous year and the R&D tax credit, this amount actually constitutes income subject to taxation and should form the basis for calculating the solidarity surcharge. He referred to Supreme Administrative Court judgments regarding the deduction of losses.
Tax Authority’s Position
The director of the National Revenue Administration (KIS) disagreed. He pointed out that the basis for calculating the solidarity surcharge is the excess over 1 million PLN of the sum of specified incomes, after deducting the amounts listed in Article 30h, section 2 of the PIT Act.
The list specified in this provision is a closed list, and therefore, only those directly specified in this regulation are deductible for the purpose of determining the amount of the solidarity surcharge. This in turn means that other deductions provided for in the annual return of a natural person, including the research and development activity deduction, are not taken into account.
The authority emphasized that the basis for calculating the solidarity surcharge should not be equated with the deductions available to the taxpayer in the annual tax return.
