Reconciliation
Two ledgers that ought to agree, and the small number of lines that do not.

NSK·SOL·01
A bank closes the day by hand. Statements arrive in four formats and the core ledger in a fifth, and the differences between them are found by eye.
Most lines pair without argument. The value sits in the handful that do not, and those are the ones the team runs out of time for.
Drag the rule across the day.
Drag the rule across the day. Lines pair as it passes; what remains is the exception list.
Statements against the core ledger, pairing first and exceptions after, so the close ends at a known list rather than a deadline.
Chargebacks, duplicates and failed settlements grouped by cause, with the rule that grouped them on the record.
Regulatory and management figures assembled from source rows, each number traceable back to the entries behind it.

Central-bank cybersecurity frameworks in each market, with PCI DSS scope held to the tokenised path.
Every pairing carries the rule that produced it and the operator who accepted it.
Records retained seven years; model output is advisory until an operator signs.
Bring us the case you have not been able to close.
We will tell you which part of it is a model problem and which part is not.