The Latin expression pro rata, often complemented as pro rata parte, constitutes a fundamental postulate of hermeneutics and the application of Civil, Procedural, and Tax Law, designating the proportional distribution of burdens, rights, or obligations among various parties. Its primary purpose is to ensure distributive equity, guaranteeing that the legal responsibility or benefit of each subject is measured in strict observance of their quota or the time of enjoyment of a given right.
1. Definition, Concept, and Legal Nature
The term pro rata derives from Latin and means "in proportion" or "according to the calculated part." In legal parlance, it refers to the apportionment criterion where the distribution of assets or liabilities does not occur in a joint or arbitrary manner, but rather in a fractional way, respecting a pre-determined mathematical ratio, whether based on invested capital, elapsed time (pro rata temporis), or the number of subjects involved.
The legal nature of the institute is that of an obligational distribution criterion. It differs from legal joint liability (solidarity) because, in the latter, each debtor is responsible for the entirety of the debt; in the pro rata application, the obligation is divisible, operating the fragmentation of the legal bond so that each debtor is responsible only for their ideal share, as advocated by the exegesis of the Law of Obligations.
2. Historical Origin and Evolution
The roots of the institute date back to Roman Law, specifically in the treatment of obligationes divisibiles. The principle nomina hereditaria ipso iure divisa sunt (hereditary debts are divided by operation of law) established that, upon the death of the pater familias, credits and debts were distributed among the heirs in proportion to their quotas, without the need for express stipulation.
In Comparative Law, the Napoleonic Code of 1804 consolidated the presumption of divisibility of obligations in the absence of express joint liability, directly influencing the Brazilian Civil Code of 1916 and, subsequently, that of 2002. The contemporary evolution of the term has expanded to Labor Law and Tax Law, where temporal proportionality (pro rata temporis) has become essential for the calculation of interest, dividends, and social benefits.
3. Legal Provision and Regulatory Framework
The application of the pro rata principle is scattered throughout the Brazilian legal system, manifesting itself in a mandatory manner in various statutes:
- Civil Code (Law No. 10.406/2002): Art. 257 establishes the presumption of divisibility: "If there is more than one debtor or more than one creditor in a divisible obligation, it is presumed to be divided into as many equal and distinct obligations as there are creditors or debtors." In the condominium scope, Art. 1.336, item I, determines the duty of the unit owner to contribute to expenses in proportion to their ideal fractions, unless otherwise provided.
- Code of Civil Procedure (Law No. 13.105/2015): Art. 87 addresses the burden of litigation: "If there are several plaintiffs or several defendants, the defeated parties shall be proportionally responsible for expenses and attorney's fees." If the judgment is silent, the distribution occurs pro rata (paragraph 1).
- Labor Law: Law No. 4.090/1962, which institutes the 13th-month salary, provides for proportional payment (1/12 per month of service) upon contract termination, applying the pro rata temporis concept.
- Tax Law: The National Tax Code (CTN), when dealing with the liability of successors (Art. 129 et seq.), often implies the proportional apportionment of tax debts linked to the transferred assets.
4. Practical Application and Consolidated Jurisprudence
The jurisprudence of the Superior Courts has focused on the pro rata application, especially regarding attorney's fees and banking contracts.
In the Superior Court of Justice (STJ), it is a settled understanding that, in the presence of a plurality of winners or losers, the condemnation to attorney's fees must be divided proportionally. The Court reinforces that joint liability is not presumed (Art. 265, CC), and the pro rata rule of Art. 87 of the CPC must be applied in the absence of judicial specification regarding each party's share.
In the Superior Labor Court (TST), the principle is vital for the calculation of Profit Sharing (PLR). TST Precedent 451 (formerly OJ 390 of SBDI-1) establishes that an employee who resigns before the PLR payment date is entitled to receive the portion proportionally to the months worked, in compliance with the principle of equality.
In the sphere of Banking and Consumer Law, the STJ applies pro rata temporis for the calculation of remuneratory interest and for the refund of insurance premiums when there is early termination of the contract, preventing the unjust enrichment of financial institutions.
5. Related Principles and Doctrinal Divergences
The pro rata institute dialogues directly with the following principles:
- Principle of Prohibition of Unjust Enrichment: Prevents a party from receiving payment for a period not worked or a party from paying for a quota that does not belong to them.
- Principle of Freedom of Contract: Although the general rule is proportional apportionment, parties may agree on joint liability, which must be express.
Doctrinally, there is a debate regarding the pro rata application in obligations that are indivisible by nature, but divisible by convention. The classical school argues that the nature of the object (e.g., delivery of a live animal) prevents immediate proportional apportionment, converting it into damages (monetary value), where the pro rata principle then resumes its full applicability.
6. Contemporary Relevance and Practical Impacts
Currently, the precision of pro rata calculation is fundamental for legal certainty in capital markets and technology contracts (SaaS - Software as a Service). The fractional billing of subscriptions and the distribution of interim dividends require a mathematical rigor that the Law absorbs through this institute.
Furthermore, in Administrative Law, the Bidding Law (Law No. 14.133/2021) uses the logic of proportionality for contractual adjustments and penalties, demonstrating that the pro rata concept is an indispensable tool of commutative justice for the balance of complex legal relationships.
Legal and Jurisprudential References
- BRAZIL. Law No. 10.406, of January 10, 2002. Civil Code.
- BRAZIL. Law No. 13.105, of March 16, 2015. Code of Civil Procedure.
- BRAZIL. Superior Labor Court. Precedent No. 451. Profit Sharing. Proportionality.
- BRAZIL. Superior Court of Justice. Special Appeal No. 1.745.333/RS. Rapporteur Min. Nancy Andrighi (Addresses the division of attorney's fees and procedural expenses).
- BRAZIL. Law No. 4.090, of July 13, 1962. Christmas Bonus for Workers.
