IRB Requirements and CLM Implications Briefing
Status: active (DRAFT v0.1) Started: 2026-04-23 (document date) Last touched: 2026-04-29
Why this project exists
A client-facing briefing paper translating Internal Ratings-Based (IRB) approach requirements into design implications for both Day 1 (legacy-architecture simplification into a consolidated golden-source target) and Day 2 (the CLM build) at the Irish Tier-1 retail bank in the CLM Transformation Programme [S-2026-04-29-paul-irb-clm-briefing].
Current state
- DRAFT v0.1, 32 pages, A4, validated.
- Saved at
~/AgentData/ClaudeAccess/Projects/03 Credit Lifecycle/Regulatory/2026-04-23 IRB Requirements and CLM Implications v0.1 DRAFT.docx. - Anchored to CRR3 (Regulation (EU) 2024/1623, in force 9 July 2024, applies 1 January 2025, 72.5% output floor phased to 2030); EBA Roadmap and Guidelines; ECB Guide to internal models (February 2024); ECB RDARR Guide (May 2024); BCBS 239 (January 2013); CBI Regulatory & Supervisory Outlook 2025–2026; CBI CP123 on materiality threshold [S-2026-04-29-paul-irb-clm-briefing].
Document structure. Cover; document control; TOC; executive summary; §1 IRB landscape; §2 definition of default and IRB data lifecycle; §3 Day 1 implications; §4 Day 2 implications; §5 cross-cutting requirements; §6 eight named recommendations; §7 eight open questions; Appendix A regulatory reference list; Appendix B glossary (29 IRB terms); Appendix C mapping table (14 IRB data inputs → system-layer path → DQ control/metric/target → owning role).
Headline Day 1 implications. Every IRB rating-model input must end up with a single governed golden source after simplification, with lineage continuity, default-history continuity, 5-year retention preserved, and a model-change impact assessment per CRR Article 143 [S-2026-04-29-paul-irb-clm-briefing].
Headline Day 2 implications. Canonical Definition of Default (DoD) logic in the CLM ODS; UTP flag set as structured capture; full IRB lineage as a named subset of the CDE register’s 100% R1 lineage target; CLM ODS as certified single source for Pillar 3 IRB templates and COREP IRB datasets; use-test evidence engineered into the CLM UI audit trail [S-2026-04-29-paul-irb-clm-briefing].
Decisions made
- 2026-04-23 — Document structure, anchors, and headline Day 1 / Day 2 implications locked.
- 2026-04-29 — DRAFT v0.1 status with 8 named recommendations and 8 open client-confirmation questions; two intentional
[TBC with client]markers remain in Document Control (Approver name and Distribution list) [S-2026-04-29-paul-irb-clm-briefing].
Eight recommendations:
- Add an IRB design lens to the CLM Design Sub-Committee.
- Tag IRB-relevant CDEs in the existing register.
- Implement canonical DoD logic in the CLM ODS.
- Treat the CLM ODS as the certified Pillar 3 / COREP source.
- Extend the BCBS 239 attestation to include named IRB capabilities.
- Engineer use-test evidence into the CLM UI.
- Govern Day 1 simplification through model-change impact assessments.
- Engage the JST early.
Open questions / blockers
Eight client-confirmation items:
- SI vs LSI status of the bank.
- Current IRB scope (PD / LGD coverage by portfolio).
- Materiality threshold parameters under CDR 2018/171.
- Model-owner mapping.
- Use-test evidence retention policy.
- Pillar 3 cadence and template-population responsibility.
- JST engagement protocol.
- Historical default-flag back-fill scope.
Connected wiki pages
- part-of → CLM Transformation Programme — parent context.
- implements → BCBS 239 and Data Lineage — underpins the lineage and attestation recommendations.
- relevant-to → Service Line — Regulatory Readiness and Evidence — briefing is the practitioner artefact.
- relates-to → CLM Data Taxonomy Governance — IRB CDE tagging in the existing register.
History
- 2026-04-23 — Document drafted.
- 2026-04-29 — DRAFT v0.1 saved; Open Brain capture recorded.