After preparing dozens of technical reports on business credit operations, one observation stands out: much of what circulates as "forensic analysis" in the market — including in court proceedings — fails a simple test: given the same contract and the same data spreadsheet, would a second, independent expert reach the same result?
If the answer is no, the document may still be a well-reasoned opinion, but it is not, technically, a forensic report. That distinction — between opinion and replicable calculation — is what this article sets out to clarify, based on recurring methodological errors observed in practice.
In this analysis
- A report isn't an opinion — it's a replicable calculation
- Error 1 — Confusing amortization systems, without stating which was used
- Error 2 — Treating a financed tax as a fixed value, ignoring gross-up
- Error 3 — Summing pathologies before isolating each one
- Error 4 — Presenting a conclusion without the model
- The criterion that separates a forensic report from an opinion
- Frequently asked questions
A report isn't a well-reasoned opinion — it's a replicable calculation
The distinction between an opinion and a technical report isn't semantic: it's what determines whether a document carries evidentiary weight equivalent to a forensic audit. And the test that separates one from the other is observable in four recurring methodological errors.
Error 1 — Confusing amortization systems, without stating which was used
The first and perhaps most common error is treating the amortization system as a secondary detail. A fixed-installment system (rising principal repayment) and a constant-amortization system (fixed principal repayment, declining installments) produce completely different outstanding-balance trajectories over time, especially when there is a grace period.
The "seesaw effect". In more than one case reviewed, contracts formally labeled as constant-amortization were identified, but whose payment flow actually behaved like the fixed-installment system — or like an undisclosed hybrid table — generating negative amortization in certain periods due to a mismatch between the declared and the actually applied system. A serious report must explicitly identify which system is being applied in fact, demonstrating it through the payment flow itself, installment by installment.
Error 2 — Treating the financed tax as a fixed value, ignoring gross-up. When the transaction tax is financed within the principal, it requires a specific calculation — gross-up — to prevent the tax itself from inflating the calculation base and, as a result, generating interest on a tax. In more than one case reviewed, this error, capitalized daily over years of contract life, produced what can be described as tax-driven compound interest. Accepting the tax figure reported by the bank without recalculating it under the applicable legal decree — including whether the correct rate (business, not individual) was applied — is not a forensic audit. It's transcribing the bank's spreadsheet.
Error 3 — Summing pathologies before isolating each one. The subtlest error, and perhaps the most serious from a methodological standpoint: summing the effect of multiple pathologies into a single "overcharge" figure without technically isolating each one. This makes the report impossible to audit — no one can tell how much of the overcharge comes from each pathology, or verify double-counting. The correct methodology isolates each pathology — undue capitalization, a tax calculation error, a disputed fee — and only then demonstrates the cumulative effect.
Error 4 — Presenting a conclusion without the model. Reports that present a final figure — "the correct outstanding balance is X" — without detailing the spreadsheet, formulas and assumptions. A non-replicable report is not auditable, and a non-auditable document should not carry more evidentiary weight than a qualified opinion. Any third party, with access to the same input data, should reach the same result following the method described.
Does the report you received pass this test?
Request a second technical opinion or a replicable counter-audit of your contract or an existing report.
The criterion that separates a forensic report from an opinion
In the end, the test is simple to state, though laborious to meet. A serious technical report must:
- Correctly identify the amortization system actually applied, not just the one declared.
- Recalculate the transaction tax according to the applicable legal methodology, including gross-up when the tax is financed.
- Isolate each technical pathology before summing their effects, making each component traceable.
- Be replicable — present the full model, not just the conclusion.
A document that meets these four criteria is a technical report. A document that presents only a conclusion, however experienced its author, is an opinion. Both have value, but not the same technical weight — and that difference is exactly what should guide anyone who commissions a forensic audit, and anyone who evaluates one.
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 difference between a forensic report and a well-reasoned opinion?
A forensic report is replicable: given the same contract and the same data spreadsheet, a second, independent expert should reach the same result. An opinion can be well-reasoned, but if it cannot be replicated by another professional using the same method, it is not, technically, a forensic report.
Why is confusing the two main amortization systems a serious error?
Because they produce completely different outstanding-balance trajectories over time, especially with a grace period. Contracts labeled as constant-amortization but whose payment flow actually behaves like the fixed-installment system generate negative amortization in certain periods — a "seesaw effect" only identified through a line-by-line recalculation.
What is IOF gross-up and why does it matter in a forensic audit?
It's the specific calculation required when the tax amount is financed within the principal, to prevent the tax itself from inflating the calculation base and generating interest on a tax. Accepting the tax figure reported by the bank without recalculating it under the applicable legal decree is transcribing the bank's spreadsheet, not performing a forensic audit.
Why is it an error to sum the effect of several pathologies into a single number?
Because it makes the report impossible to audit: no one can tell how much of the overcharge comes from each pathology specifically, or verify whether any was double-counted. The correct methodology isolates each pathology — undue capitalization, a tax calculation error, a disputed fee — before adding up the cumulative effect.
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 →