Among the credit instruments offered to Brazilian small and medium-sized companies, the revolving credit line ("conta garantida") is usually pitched as the simplest and most flexible: a revolving limit attached to the checking account that the company draws on and repays according to its cash needs. The technical problem forensic review repeatedly finds isn't in using the line within the contracted limit — it's in what happens afterward, once the limit is exhausted and the bank starts treating the remaining balance under rules rarely explained clearly to the client.
In this analysis
The case: from R$50,000 to nearly R$190,000
In one of the expert opinions underlying this analysis, a company contracted a revolving credit line with a limit of roughly R$50,000 from Banco Daycoval. The contracted nominal interest rate was 15% per month — roughly 435% annualized — a level far above not just the market average reported by Brazil's Central Bank (close to 4% per month for this type of product), but also above that same bank's own average for its operations (around 2.9% per month).
The forensic review identified not just that elevated rate, but a sequence of mechanisms that, combined, multiplied the debt within a few months:
First — fees capitalized on a zeroed-out account. With the limit fully used, fees kept being debited and financed even with the account balance at zero — generating interest capitalization on charges that were already controversial by themselves.
Second — a fee on the excess generated by the interest itself. The "over-limit" balance created by these elevated interest charges then began to draw an additional fee — a charge triggered by the abusive interest's own behavior, not by any credit-consumption decision by the company.
Third — unilateral conversion to a depositor advance. The most serious point: the balance was unilaterally converted into a very-short-term emergency credit modality, at an even higher cost, with no clear, explicit basis for that conversion in the original contract.
Fourth — 15% monthly default interest, capitalized daily. On the new balance, default interest of 15% per month began to apply, capitalized daily.
Was your revolving credit line converted to another modality without notice?
Request a technical reconstruction of your statement, month by month, before accepting the charge.
Why the modality conversion is the central issue
Technically, the problem isn't only the high rate itself — elevated rates on unsecured revolving credit are not, in isolation, always abusive. The problem is the change of contractual regime with no clear basis and no renewed consent. A revolving-line contract sets a set of rules for using the limit within its active term. When that limit is exhausted or the term expires, the legal relationship between the parties cannot, automatically and with no express contractual basis, migrate into a different, more expensive product as though it were a natural clause of the same agreement.
This kind of conversion — from revolving credit into emergency modalities like a depositor advance — finds support, in the forensic analysis, in arguments tied to the need for legal cause for any obligation (credit cannot be created from nothing, by the lender's unilateral decision) and the prohibition on unjust enrichment, along with Superior Court of Justice (STJ) precedents limiting charges on revolving lines and overdraft facilities.
The aggravating factor of disproportionate collateral
A second point stands out in this and similar cases: the disproportion between the original limit and the collateral demanded. For a limit of roughly R$50,000, the contract involved real estate worth significantly more and the signature of six individual guarantors. That disproportion is not, by itself, illegal — but it becomes relevant once the balance later "explodes" through the bank's own unilateral mechanisms: the guarantors and the pledged property end up exposed to a debt multiplied by factors they could never have anticipated when signing.
What to check before contracting (or renewing) a revolving credit line
- What contractually happens when the limit is exhausted — is there an automatic conversion to another modality, and if so, is it described transparently?
- What default-interest rate applies after the limit's maturity, and does it capitalize daily or monthly?
- Is a fee charged on the very over-limit balance generated by the product's own charges?
- Is the required collateral proportional to the contracted limit, or disproportionately robust for a product marketed as "low risk"?
When a revolving credit line's balance grows in a way that seems disconnected from actual limit usage, it is worth pursuing a technical, month-by-month reconstruction of the statement before accepting the charge as final.
This article is part of a series on technical pathologies in business credit operations, based on expert opinions prepared by the author. Individual cases are treated in aggregate and anonymized form, with no identification of the companies or individuals involved.
Frequently asked questions
What is the conversion of a revolving credit line into an emergency depositor advance?
It is the unilateral migration of a revolving-line balance into a very-short-term emergency credit modality, at an even higher cost, applied by the bank with no clear, explicit basis for that conversion in the original contract.
Why isn't a high rate on a revolving credit line always abusive by itself?
High rates on unsecured revolving credit are not, in isolation, always abusive. The central technical problem is the change of contractual regime with no clear basis and no renewed client consent after the original limit matures.
What is the legal basis in Brazil for challenging this kind of unilateral conversion?
Arguments tied to the need for legal cause for any obligation, the prohibition on unjust enrichment, and Superior Court of Justice (STJ) precedents limiting charges on revolving lines and overdraft facilities.
What should I check before contracting or renewing a revolving credit line in Brazil?
What contractually happens when the limit is exhausted, the applicable default-interest rate and whether it capitalizes daily or monthly, whether a fee is charged on the very excess generated by the product's own charges, and whether required collateral is proportional to the contracted limit.
Dr. Lincoln Sposito
Specialist in banking audits and financial forensics, combining the statistical rigor of data science with the analysis of banking-system architectures to dismantle predatory charges against SMEs. Learn more about the expert →