Consumer Credit
Lending and Calculation Logic Under Regulatory Challenge
Interest miscalculated at scale, with no record of why the logic had been set up the way it was.
Illustrative engagement
The engagement
Where the decision had to hold under scrutiny
Interest on Buy-Now-Pay-Later balances had been calculated incorrectly over time, affecting large numbers of customers and creating regulatory risk. The lack of clear validation and oversight allowed errors to persist unnoticed, and there was no record of why the logic had been set up as it was. Illustrative work undertakes a full review of calculation logic and introduces controls to test, monitor, and evidence outputs. This supports remediation and helps ensure the logic is accurate, controlled, and able to withstand scrutiny.
Key challenges
The problem, and what was done about it
Challenge 01
Interest was being calculated incorrectly across large numbers of customers, and with no validation or monitoring in place the errors persisted unnoticed for a long time.
What was done
Ran a full review of the calculation logic and introduced controls to test, monitor, and evidence outputs, so divergence would be caught early and correct figures could be proven for remediation and redress.
Challenge 02
There was no record of why the calculation logic had been configured as it was, making it impossible to justify to the regulator or to scope redress fairly.
What was done
Reconstructed and documented the intended logic and its basis, giving remediation and customer redress a defensible, evidenced foundation.
Illustrative — reconstructed from the engagement context
How Verdica makes it defensible
The same five stages, applied to this decision
Every engagement runs the same path. For this one, the weight falls on Reason, Assure, Evidence — the stages where a decision of this kind is most often challenged.
Trace
Map every point where the decision could be challenged — before a line of logic is written.
Reason
Build the logic in the open: explainable, deterministic, same input, same output — no black box.
Assure
Validate coverage and oversight before anything ships; nothing unassessed is waved through as safe.
Certify
Lock an immutable, versioned record of exactly what was decided and on what basis.
Evidence
Hand over the audit trail — the pack that holds the moment someone says prove it.
Related engagements
The same standard, holding elsewhere
Discuss a related situation
A decision like this can be made defensible — on the record, not after the fact
A short discussion is usually enough to locate where the risk sits — in the logic, the controls, the evidence, or a combination — and where Verdica makes it hold.