A full-lifecycle credit-risk study: originate, price, provision, and collect, built on four real public datasets using standard model-risk-governance conventions (SR 11-7, RBI MRM, Basel III, IFRS 9). Each model is measured against a simple baseline, a bureau-score cutoff and its equivalents, the kind of benchmark a lender relies on before it builds a full custom scorecard.
The deliverable is not a higher Gini. It is a better business frontier: at the benchmark's operating point, approve more good borrowers and fewer bad ones, and reduce credit losses across the book's life.
Scope note: the "Champion" throughout is a bureau-score benchmark, not a mature lender's production scorecard. The results show the lift a custom model adds over a generic bureau score. They are not a claim to beat an established underwriting process. See Scope and honest limitations.
On a held-out test set of 61,503 loans, a custom PD model is benchmarked against a bureau-score cutoff, the baseline a lender uses before a full scorecard exists.
| Bureau-score benchmark (Champion) | Custom (Challenger) | |
|---|---|---|
| Discrimination (AUC) | 0.718 | 0.756 |
| At matched volume | 3.69% default | 2.95% default (-20%) |
| At matched risk | 50% approval | 63.6% approval (+27%) |
Recommended operating point (SC3): 61.9% approval, 3.61% default, +₹176 cr net income, +93.4% portfolio RAROC - higher approval and lower default than the bureau-score benchmark, simultaneously. The income-maximising point within risk appetite sits at 63.7%; the recommended point is held one step inside it to strictly beat the benchmark on every metric.
flowchart LR
subgraph Data
D1[Home Credit]
D2[Give Me Some Credit]
D3[LendingClub]
D4[Freddie Mac panel]
end
subgraph Modules
A[A - Application PD]
B[B - Behavioural]
C[C - Portfolio and Pricing]
E[D - IFRS 9 ECL and Staging]
end
G[Decision Engine - RAROC gate]
P[Provisioning - IFRS 9 ECL]
GV[Governance - SR 11-7, RBI MRM, Basel III]
D1 --> A
D2 --> B
D3 --> C
D4 --> E
A --> G
B --> G
C --> G
G --> P
E --> P
P --> GV
The PD model estimates risk; the RAROC gate sets policy on the frontier; the IFRS 9 engine turns staging into a provisioning decision; governance closes the loop with monitoring and regulatory alignment. The four modules are trained on four independent datasets; the decision engine that combines their signals is a reference architecture, not a single scored book (see limitations).
Each module measures a custom Challenger against a simple benchmark, the kind of baseline a lender uses before building a custom model, and reports the lift on discrimination and on the business outcome.
| Module | Question | Benchmark (Champion) | Custom | Lift vs benchmark |
|---|---|---|---|---|
| A Application | Who to approve? | Bureau score (0.718) | Full PD model (0.756) | +27% volume / -20% default |
| B Behavioural | How is the borrower behaving? | Past-DPD rule (0.768) | Behavioural ML (0.860) | catches 81% vs 71% of delinquents |
| C Portfolio | Is the rate right? | FICO + grade (0.705) | Full model (0.729) | +3.7pp approval / -4.9% default |
| D ECL & Staging | What is the lifetime loss? | Snapshot proxy | Panel staging on 12.6M loan-months | 39x Stage 1 to Stage 2 provisioning cliff, real LGD 41.8% |
Module D's transition matrix (28.5% monthly Stage 2 to Stage 1 cure rate) and vintage curves (2008 crisis 6.0% vs 2011 1.1% default) drive the IFRS 9 ECL-reduction case: better origination keeps loans in Stage 1, and collections cure Stage 2 back before the lifetime-ECL cliff.
01_module_a_application_risk/ Module A - origination PD, scorecard, RAROC, swap-set
02_module_b_behavioural_risk/ Module B - delinquency model, collections capture
03_module_c_portfolio_pricing_risk/ Module C - grade / market-implied PD, pricing
04_module_d_ecl_ifrs9/ Module D - IFRS 9 staging, transition matrix, lifetime ECL
04_decision_engine/ Composite signal, RAROC gate, audit trail
05_governance/ Model cards, SR 11-7, RBI MRM, regulatory alignment
06_docs/ Executive deliverables and methodology (HTML)
Each module follows the same layout: 01_data/ (raw is gitignored, download separately), 02_notebooks/, 03_models/, 04_outputs/.
The decision engine runs with no data download:
pip install -r requirements.txt
python 04_decision_engine/demo.py # scores 4 sample applicants end to endTo regenerate every figure from raw data, place the datasets (see Data) and run:
python run_all.py # runs the module pipelines in order, on a fixed seed
python run_all.py --check # lists which raw datasets are present / missing first
python tools/run_notebooks.py # re-execute notebooks whose data is present (refreshes outputs)run_all.py skips any module whose raw data is absent and tells you where to get it, so a partial checkout still runs what it can. Every figure in the documentation is regenerated by these pipelines on a fixed seed (42).
This is a portfolio study on public data, built to institutional conventions. Read the results with these caveats, which the analysis itself states rather than hides:
- The Champion is a bureau-score benchmark, not a production scorecard. The lift shown is over a generic bureau-score cutoff, the baseline before a custom model exists. It is not a claim to beat a mature lender's existing underwriting.
- The integration is illustrative. The four modules train on four unrelated public datasets (different borrowers, geographies, eras). The composite PD and decision engine show how the signals would combine; they are a reference architecture, not one book scored end to end.
- Module A's origination "staging" is a PD-bucket proxy, not SICR-based IFRS 9 staging. A single application snapshot cannot express a significant increase in credit risk. All credible IFRS 9 staging in this project is Module D, on the Freddie Mac monthly panel.
- The collections uplift / next-best-action model is exploratory. It uses loan modification as an observed (not randomised) treatment, so the effect is confounded, and its uplift-decile validation is not yet monotonic. Treat it as a targeting hypothesis, not a causal result.
- Data is public Kaggle / Freddie Mac. Figures are realistic and reproducible, but they describe these datasets, not a live portfolio.
Built to the following conventions (not a formal validation):
- SR 11-7 - model development, validation, monitoring; champion vs challenger; audit trail.
- RBI MRM - model inventory, risk-tier classification, model cards per module.
- Basel III / ICAAP - EL, RWA, economic capital, four-scenario stress testing.
- IFRS 9 - Stage 1 / 2 / 3 allocation, lifetime PD from the survival curve, ECL by stage.
- Fair Practices - adverse-action notices with plain-language reason codes.
Home Credit Default Risk · Give Me Some Credit · LendingClub 2007-2018 · Freddie Mac Single-Family Loan Performance (2008-2011). Raw files are downloaded separately and are not committed.
A portfolio study in credit risk: reduce risk, increase real profitability. Every figure traces to an executed pipeline and is built to standard risk conventions.