A02 · TOPIC · model-and-ai-riskGRA dossier · service level R0
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Topic dossier · Banking Nexus

Model and AI risk

Banks rely on models to grant credit, set provisions, price products, compute capital and detect fraud, and a growing share of those models use machine learning. Model risk is the potential for loss or poor decisions when a model is wrong or misused. This page sets out how model and AI risk arises, how validation and governance contain it, and which supervisory and legal frameworks now apply to automated credit decisions.

01In brief

The short answer.

Model risk is the potential for loss or poor decisions when a model is wrong or misused. Banks rely on models to grant credit, set provisions, price products, compute capital and detect fraud, increasingly with machine learning, so drift, opacity, bias and herding are governed through model risk management and validation.

02Spatial finance

From a satellite tile to an exposure update.

How satellite radar turns a flood into an exposure update. Synthetic scene; no real event or place.

How satellite radar maps a flood and updates the count of affected buildings.Synthetic scene and schematic model; no real event or place.
03The question

Model and AI risk: how the risk develops.

Credit automation and validation. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.

Mechanism

Drift and regime change

Models learn from past data. When the economy, customer behaviour or products change, relationships shift and accuracy decays, often quietly until losses or complaints reveal it.

Mechanism

Opacity weakens challenge

Complex machine learning models can be hard to explain to credit officers, customers and supervisors. Effective challenge, a pillar of model governance, is weaker when no one can say why a model decides as it does.

Mechanism

Bias produces unfair outcomes

Training data reflect past lending patterns. Variables that proxy for protected characteristics can produce discriminatory outcomes, adding conduct, legal and reputational risk to credit risk.

Mechanism

Models interact and herd

Many banks use similar vendors, data and techniques. Common models can produce herding in credit supply or market responses, and errors compound when one model's output feeds another.

04Key terms

Terms used on this page.

Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.

TermDefinition
Model risk managementThe governance, development standards, validation and inventory controls that limit model risk, as US guidance SR 11-7 sets out.
Population stability indexA measure of how much the distribution of a model's input or score has shifted since development.
High-risk AI systemUnder the EU AI Act, a category that includes AI used to evaluate the creditworthiness of individuals.
05Indicators

What is measured, and how well.

Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.

IndicatorUnitCadenceSource typeLabel
Model inventory coveragecount of models by tier and validation statusquarterlyModel risk management recordsREPORTED
Discriminatory power of credit scorecardsGini coefficient or area under the curveannualModel validationMODELLED
Population stability indexdimensionlessmonthlyModel monitoringOBSERVED
Calibration gap of default predictionsdifference between predicted and observed default ratesannualBack-testingOBSERVED
Overdue validation findingscount by severityquarterlyModel risk reportsREPORTED
Approval rate ratio across groupsratio of approval ratesannualFair lending analysisESTIMATED
Overrides of automated decisionsshare of decisions overriddenmonthlyCredit decision logsOBSERVED
06Canvas

From sources to decisions.

The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.

Pipeline canvas · Model and AI risk as a run graphDesign, not a record
Model and AI risk: model risk lifecycleEvery model is inventoried and tiered; development is documented; independent validation tests conceptual soundness, outcomes and benchmarks; approval sets limits of use; monitoring and periodic review keep it current until it is retired. Design of the process, not a record of a run.

Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.

07Sources

Where the evidence comes from.

Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.

SourceWhat it givesLicence class
Federal Reserve and OCC supervisory guidance on model risk management (SR 11-7)Expectations for model development, validation and governancePublic domain
PRA supervisory statement on model risk management principles for banksUK principles for model identification, governance and validationFree, Bank of England terms of use
ECB guide to internal modelsSupervisory expectations for internal ratings-based and other internal modelsFree, attribution
EBA follow-up report on machine learning for IRB modelsSupervisory analysis of machine learning in credit risk modelsFree, attribution
US Home Mortgage Disclosure Act dataLoan-level application and decision data used in fair lending analysisPublic domain
FSB and BIS reports on artificial intelligence in financeAssessments of financial stability implications of artificial intelligenceFree, attribution
08Decisions

Who decides, and what the evidence serves.

Banking Nexus prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.

Who decidesThe questionEvidence this page serves
Bank board and model risk committeeWhat model risk appetite to set and which uses of AI are acceptableModel inventory, tiering and validation findings
Independent model validation functionWhether a model is fit for purpose and what conditions or limits apply to its useBack-testing, benchmarking, explainability and fairness tests
Prudential and conduct supervisorsWhether internal models can be approved for capital and whether automated decisions treat customers fairlyValidation reports, outcome data and governance evidence
Data protection and market surveillance authoritiesWhether credit scoring systems meet legal duties on transparency, accuracy and human oversightTechnical documentation, impact assessments and testing records

Outputs this topic produces

  • Guides to validating machine learning credit models, including explainability and fairness tests
  • Comparisons of model risk management expectations across jurisdictions
  • Research on herding and concentration in AI vendors and data
  • Briefings on how the EU AI Act and similar rules apply to credit scoring
09Core questions

Shared questions the industry asks.

  1. 01

    Do models perform as intended?

    Whether models remain accurate and stable outside the conditions they were built on.

  2. 02

    Can decisions be explained?

    Whether credit decisions made with complex models can be explained to customers and supervisors.

  3. 03

    Are outcomes fair?

    Whether models produce unjustified differences across groups.

  4. 04

    What happens when many banks use similar models?

    Whether shared models and data create correlated decisions.

10Mechanisms

How the risk arises and transmits.

Model risk arises from errors in design, data or use, and from using models beyond their intended scope. It can cause losses, mis-priced risk and unfair treatment.

Machine learning can capture complex patterns but may rely on spurious correlations, degrade as conditions change and resist explanation. Validation must test not only accuracy but stability, bias and behaviour in stress.

Data quality and representativeness shape outcomes. Models trained on historical decisions can reproduce past exclusion; alternative data can widen access or introduce new biases.

Herding is a systemic concern. If many lenders use similar models, vendors or data, they may tighten or loosen credit together, amplifying cycles.

Generative AI introduces new risks in customer service, coding and document analysis, including fabricated outputs and data leakage, which require controls and human oversight.

11Methods and limits

How evidence is gathered, and where it stops.

Method or dataWhat it showsIts limit
Independent validationModel soundness and limitsDepends on validator independence and skill
Back-testingPerformance against outcomesPast conditions may not recur
Fairness testingDifferences across groupsChoice of fairness metric matters
Monitoring for driftChanges in performanceDetects problems after they emerge
12Methods

How it is studied, and what the methods cannot say.

  1. Artificial intelligence and machine learningCredit decisioning with explainability · Early warning and transaction monitoringApplied here
  2. Probability and statisticsEstimating default and loss parameters · Operational loss modellingApplied here
  3. Financial and risk engineeringExpected credit loss modelling · Counterparty exposure and valuation adjustmentsApplied here
  4. Financial economics and macro-financeMacro-financial stress scenarios · Credit cycle and buffer calibrationApplied here
13Questions

Questions and answers.

What is model risk?
The potential for adverse consequences from decisions based on incorrect or misused model outputs, whether from errors in design, data, implementation or use.
Is machine learning allowed in regulatory capital models?
Supervisors have not prohibited it, but internal models must meet requirements on explainability, data, validation and governance that complex techniques can find harder to satisfy.
How is credit scoring treated under the EU AI Act?
AI systems used to evaluate the creditworthiness of natural persons are classed as high risk, which brings requirements on risk management, data governance, transparency and human oversight.
Does GRA validate banks' models?
No. It validates no model and assesses no firm. It researches validation methods and shared risks.
Is AI in credit decisions harmful?
It can widen or narrow access, depending on design, data and governance. Research examines both effects.
Why is herding a concern?
Because correlated decisions across lenders can amplify credit cycles even if each model is sound on its own.
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