The classic trap
The CSSF regularly sanctions institutions that measure interest rate risk only on the trading book, forgetting the banking book. Article I.8 is explicit: interest rate risk inherent to non-trading activities must be measured, monitored and limited with the same rigour. The CSSF expects rate risk to be measured under several shock scenarios (parallel shift, steepener, flattener following the six EBA IRRBB scenarios), a modified duration adjustment for debt securities, and clear governance (limits approved by the supervisory body, reporting to the risk committee). The absence of a documented IRRBB stress test, or a modified duration calculation not reviewed for several years, is a recurring finding during on-site inspections.
Practical IRRBB pitfalls
- Measuring risk only on economic value (EVE) without computing the impact on net interest income (NII) over a rolling 12-month horizon.
- Using behavioural assumptions on non-maturity deposits (NMD) that have never been backtested, whereas the CSSF requires an annual review at minimum.
- Neglecting the modified duration adjustment on floating-rate debt securities or those with embedded options (callable, puttable, caps/floors).
- Failing to apply the EBA outlier test (EVE loss exceeding 15% of Tier 1 under any of the six scenarios) which triggers an immediate supervisory dialogue.
- Confusing basis risk (between Euribor 3M and Euribor 6M) with repricing risk, with no separate limit in place.
- Absence of independent IRRBB model validation by the risk management function or internal audit.
How Luxgap automates this risk
Our Luxgap IRRBB Sentinel turns your interest rate risk calculation from a quarterly Excel exercise into a continuous simulation engine that recomputes EVE, NII and modified duration nightly across your entire banking book. The tool connects directly to your core banking system (Olympic, Avaloq, Temenos T24, Sopra), your treasury system (Kondor+, Calypso, Murex) and the ESTR/Euribor curve published by the ECB, without requiring the risk officer to manually reprocess cash flows.
- Automatically computes the six EBA IRRBB shock scenarios (parallel up/down, steepener, flattener, short rates up/down) on EVE and NII, and triggers an alert if the 15% Tier 1 outlier threshold is breached.
- Applies modified duration adjustment to each debt security taking into account embedded options (callable, floors, caps) through a Black-Karasinski model calibrated on Bloomberg implied volatility.
- Monthly backtests behavioural assumptions on non-maturity deposits (stability rate, average duration) against actual flows and flags any deviation exceeding 10%.
- Generates ready-to-submit IRRBB prudential reporting in CSSF format (EBA/GL/2022/14 templates) with full audit trail on the assumptions used.
- Produces a timestamped independent validation file, admissible during an on-site inspection, demonstrating compliance with chapter 8 of 12/552 and EBA IRRBB guidelines.
- Alerts the risk committee in real time via Teams or email as soon as an internal limit approved by the supervisory body is breached, with automatic hedging proposals (interest rate swap, FRA).
Available as a complement to a Luxgap CISO mandate or as a dedicated SaaS module depending on your scope. Request a tailored quote and our teams will prepare a demonstration on your actual banking book, with a free 48-hour white audit to measure your IRRBB exposure before any commitment.
