Between two disputing merchants, accounting books may be the deciding factor. But many business owners do not realize that their books are a double-edged sword: they may prove your right, and they may be used against you. The Law of Evidence set precise rules for the probative value of merchant books, centered on one core element: regularity. Here is a practical guide for merchants and companies explaining when your books are evidence, and how to keep them on your side.
The first rule: books are not evidence against non-merchants
The text is clear: merchant books are not evidence against non-merchants. So if your opponent is an ordinary consumer (a non-merchant), you cannot prove your debt against them merely by its entry in your books.
But the law left an opening: the data recorded in the books may serve as a basis allowing the court to administer the supplementary oath to whichever party's position is stronger, in matters that may be proven by witness testimony. That is, your books may bolster your position without being conclusive evidence in themselves against a non-merchant.
The second rule: between two merchants — regularity is the key
Here the core of the matter appears. The probative value of books between one merchant and another depends on whether they are regular or not:
Mandatory regular books = evidence for their owner. Mandatory regular commercial books are evidence for their owner-merchant against their opponent-merchant. That is, the regularity of your books makes them a weapon by which you prove your right. But this probative value lapses by proving the contrary of what they contain through all means of proof, including the opponent's regular books.
Why is regularity decisive?
Regularity is not a formal detail — it is what transforms your books from mere papers into evidence by which you prove your right before the courts. Random or deficient books lose you this advantage entirely. Investing in regular, accurate accounting is not merely a regulatory obligation, but direct legal protection.
The third rule: your books may be evidence against you
Here is the other edge of the sword. Mandatory books — whether regular or irregular — are evidence against their owner-merchant in what their opponent relies on (whether a merchant or non-merchant).
The subtle point: in this case, the entries in the favor of the books' owner are also evidence for them. That is, the opponent cannot take from your books what harms you and leave what benefits you — they must either take them whole or leave them. This is the principle of "indivisibility of evidence."
The rule on refusing to produce books
An important practical situation: if one of two merchants relies on their opponent's books and accepts in advance what they contain, then the opponent refuses without justification to produce their books or allow access to them — the court may administer the supplementary oath to the one who relied on the books, regarding the validity of their claim.
In other words, hiding your books may turn against you, for unjustified refusal weakens your position rather than strengthening it.
A note on private papers
The law distinguished between commercial books and private papers. Private books and papers — even if recorded digitally — are not evidence against the one from whom they issued except in two cases: if they expressly stated therein that they received their debt, or if they expressly stated therein that they intended what they recorded to serve as a deed for the benefit of a person. In both cases, if what is recorded is unsigned, the contrary may be proven by all means.
The practical lesson for merchants and companies
Your accounting books are not merely an administrative tool — they are a legal record that may one day be presented before a judge. Make them:
- Regular: accurate, sequential entries in accordance with accounting principles, for this is what gives them probative value in your favor.
- Consistent with your documents: every entry supported by an invoice, deed, or contract.
- Continuously updated: do not leave them delayed or deficient.
Conclusion
A merchant's books are a mirror of their dealings before the courts — reflecting their right if regular, and possibly revealing what is owed by them if their opponent relies on them. The golden rule: keep your books regularly and accurately as if they will be presented before a judge tomorrow — for regular books protect you, and randomness strips you of your strongest evidence in commercial disputes.
How does LEXIUM help?
We assess the state of your accounting records from the angle of their evidentiary value, determine whether they strengthen your position or expose you to risk in a potential dispute, and prepare the appropriate proof strategy in your existing commercial disputes.
Disclaimer: This article is for general informational purposes only and does not constitute legal advice. See our full disclaimer.