Introduction
Interest rate fluctuations significantly impact banking institutions, particularly those heavily reliant on deposit-based funding. In response to evolving market conditions and regulatory scrutiny, the European Banking Authority (EBA) has issued updated guidance on implementing the IRRBB framework. While not setting new mandatory requirements, this guidance provides best practices for supervisors and institutions to refine their IRRBB risk management strategies. The framework is designed to foster a shared understanding of IRRBB risks and their assessment, emphasizing proportionality based on an institution’s size, complexity, and business model.
Implementing IRRBB guidance presents several challenges for banks due to the intricate nature of interest rate risk and its behavioral assumptions. One of the primary difficulties is the accurate modelling of non-maturity deposits (NMD), which lack fixed repricing dates and require complex behavioral assumptions. Variability in customer behavior, influenced by economic cycles and competitive market conditions, further complicates this process. Additionally, banks face operational difficulties in aligning IRRBB measurement systems with internal risk management frameworks. Many financial institutions struggle with data availability and quality, particularly when historical trends do not provide a clear basis for future projections. Another challenge is the need for sophisticated risk models that comply with regulatory expectations while also being practical and efficient for internal decision-making. Hedging strategies add another layer of complexity, as institutions must balance risk mitigation with profitability, ensuring compliance with evolving supervisory requirements. Given these difficulties, banks must continuously refine their IRRBB frameworks and integrate more granular, data-driven approaches to risk assessment.
Background: Evolution of IRRBB Guidance
The Basel Committee on Banking Supervision (BCBS) first introduced guidance on IRRBB as part of the Basel II framework, emphasizing qualitative and quantitative approaches to managing interest rate risk in the banking book. The 2016 revision, “Standards—Interest Rate Risk in the Banking Book,” outlined Pillar 2 requirements, urging banks to develop robust internal measurement systems (IMS) for IRRBB exposure assessment. The BCBS also introduced standardized shock scenarios to gauge the economic value of equity (EVE) and net interest income (NII) sensitivities. Various global regulators, including the European Union, the United States, and the United Kingdom, have since incorporated these principles into their supervisory frameworks.
The European Banking Authority (EBA) aligned its 2022 IRRBB guidelines with Basel’s recommendations, emphasizing supervisory expectations, internal stress testing, and prudent assumptions on non-maturity deposits (NMD). The latest 2025 EBA IRRBB Heatmap Implementation Report further refines these aspects by providing empirical insights into behavioral assumptions, commercial margins, and hedging strategies. The evolution of IRRBB guidance highlights the increasing focus on data-driven supervision and institution-specific risk mitigation techniques.
Non-Maturity Deposits (NMD) Modelling
Non-maturity deposits (NMD) are liabilities without a fixed maturity date, making their behavioral modelling complex. These deposits, which account for over 50% of liabilities for many European banks, require careful segmentation and benchmarking to assess their repricing behavior accurately. The EBA report recommends incorporating risk factors such as customer demographics, institutional characteristics, and economic conditions into behavioral modelling. Supervisory tools, including stress testing, historical data analysis, and peer benchmarking, can help refine these assumptions, ensuring institutions maintain an accurate and forward-looking IRRBB risk framework.
Supervisory Outlier Test (SOT) and Its Complementary Dimensions
The Supervisory Outlier Test (SOT) is a regulatory test designed to assess an institution’s vulnerability to sudden interest rate shocks by measuring the impact on net interest income (NII) and the economic value of equity (EVE). While exceeding the SOT threshold does not automatically trigger supervisory action, the EBA suggests additional financial dimensions should be considered to provide context to an institution’s IRRBB exposure. These dimensions include market value changes in fair value instruments, interest-sensitive fees and commissions, and embedded gains/losses due to observed interest rate movements. This broader assessment aligns with Basel’s Pillar 2 approach, which encourages regulators to consider multiple risk factors beyond standardized metrics.
Modelling Commercial Margins of NMD in the SOT on NII
A commercial margin represents the difference between the interest earned on assets and the interest paid on liabilities. This margin plays a crucial role in NMD modelling, as it affects an institution’s projected net interest income. The EBA clarifies that institutions should align SOT calculations with their internal measurement systems. Where specific modelling assumptions are absent, a constant spread over the risk-free rate should be applied. Key considerations include the current spread environment, the proximity to a zero/negative interest rate scenario, and lag effects in pass-through rates. Institutions are encouraged to maintain conservative and forward-looking approaches in their modelling strategies, ensuring IRRBB projections remain aligned with prevailing market conditions.
Hedging Strategies for IRRBB
Hedging is a financial strategy used to mitigate risk exposure to adverse market movements, including interest rate fluctuations. The EBA report highlights that European banks predominantly use interest rate swaps to manage open IRRBB positions after accounting for natural hedges. The effectiveness of these strategies varies, with 40% of institutions that use derivatives potentially breaching regulatory outlier thresholds in their absence. The guidance emphasizes that institutions should deploy derivatives solely for risk mitigation rather than speculative gains. Additionally, the repricing characteristics of NMD should not be artificially adjusted to reflect asset repricing profiles, ensuring accurate risk modelling.
Implications for Risk Management and Treasury Functions
The EBA’s guidance reinforces the importance of an integrated approach to IRRBB risk management. Risk managers and treasury teams must enhance NMD modelling frameworks, incorporate broader financial dimensions into IRRBB assessments, align commercial margin assumptions with internal risk methodologies, and optimize hedging strategies for genuine risk mitigation. These measures contribute to the institution’s overall resilience against IRRBB shocks and ensure compliance with evolving regulatory expectations.
References
Basel Committee on Banking Supervision. “Standards—Interest Rate Risk in the Banking Book.” Bank for International Settlements, 2016.
European Banking Authority. “EBA Guidelines on IRRBB and CSRBB.” EBA, 2022.
European Banking Authority. “IRRBB Heatmap Implementation Report.” EBA, 2025.
European Commission. “Commission Delegated Regulation (EU) 2024/856 on Supervisory Outlier Tests.” Official Journal of the European Union, 2024.
European Central Bank. “Supervisory Review and Evaluation Process (SREP).” ECB, 2023.
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