IFRS quantitative finance series
IFRS 9 Model Risk Governance for Banks
IFRS 9 sits at the intersection of credit risk, finance, economics, data and accounting policy. Governance fails when each team controls only its component and no accountable owner controls the end-to-end estimate.
Define the decision chain
Policies should allocate responsibility for staging, parameters, scenarios, overlays, accounting entries and disclosures. Model approval does not approve the entire allowance: data, operation, judgement and aggregation require their own controls.
Independent challenge
Validation should have sufficient authority and competence to challenge conceptual soundness, data, implementation and outcomes. Independence is strengthened by transparent issue grading, direct escalation and clear rules for use under limitation.
Change without losing comparability
Model and policy changes need impact analysis, parallel runs and movement attribution. A better model may legitimately change ECL, but stakeholders must understand how much came from portfolio movement, economic outlook, methodology and correction.
Quantitative expression
Implementation controls
- Name one accountable end-to-end allowance owner.
- Maintain limitations and compensating controls.
- Require impact analysis for every material change.
- Preserve reproducible evidence for audit.