The European Central Bank has reshaped how it supervises banks' internal models for calculating capital requirements, moving from pre-approval scrutiny to post-implementation assessment in a reform designed to reduce regulatory friction while preserving financial stability. The shift, effective 1 October 2026, represents a significant change in how Europe's primary banking supervisor balances speed and safety in an increasingly complex risk landscape.
Under the new framework, banks can implement material changes to their internal models for credit risk shortly after submitting a complete application package, provided their internal control functions credibly confirm that the revised model complies with regulatory requirements and that the bank is ready to implement the change. This marks a departure from the traditional ex ante approach, where supervisors conducted reviews before any changes took effect—a process that often forced banks to maintain old and new models in parallel while awaiting approval, creating operational inefficiencies and delayed risk management improvements.
SAFEGUARDS EMBEDDED IN REFORM
The ECB has constructed guardrails into this accelerated process to prevent regulatory arbitrage. Where model changes result in lower risk weights—and thus lower capital requirements—banks receive fast approval to implement the new model, but the regulatory capital benefit will be constrained by a floor. Such a floor will be applied to all approved model changes and can be lifted only once the ECB has thoroughly assessed the features of the new model through a targeted on-site investigation. For sensitive cases, the ECB retains the option to follow the standard approval process, requiring banks to await the outcome of a dedicated on-site investigation before implementation.
The reform builds on several years of supervisory work to make banks' internal models more reliable and consistent. In 2025, the ECB conducted 74 on-site investigations of internal models, with more than 90 percent triggered by initial model approvals or material changes, including changes to address findings from previous ECB reviews. Under the new regime, material model changes will no longer automatically trigger investigations, freeing supervisory resources for higher-risk areas.
RISK-BASED SUPERVISORY PIVOT
The ECB is shifting toward a more proactive, risk-based supervisory approach. On-site investigations will now focus primarily where higher risks warrant closer scrutiny, such as models exhibiting outlier behaviour in horizontal analyses or those that may show weaknesses in a changing macroeconomic environment. This allows the ECB to supervise these models in a more targeted and risk-based manner.
Complementing this supervisory evolution, the European Banking Authority released a revised Regulatory Technical Standard for assessing the materiality of changes to internal models for credit risk. The EBA recalibrated the materiality criteria, with greater reliance on quantitative thresholds and more targeted qualitative triggers. This substantially reduces the number of changes classified as material, and therefore subject to ECB approval, while preserving appropriate supervisory visibility.
STRATEGIC PORTFOLIO FOCUS
The ECB continues to encourage banks to focus their internal models on strategic loan portfolios and to switch to the standardised approach when the models apply to small portfolios, rely on limited representative data, require high operational effort or are expensive to maintain. This guidance reflects supervisory recognition that internal models, while valuable for sophisticated risk management, can become challenging when applied to marginal business lines.
The reform addresses a longstanding tension in European banking regulation: supervisors need sufficient time to validate complex mathematical models, yet excessive approval timelines create competitive disadvantages and operational drag. By shifting the approval burden to post-implementation assessment backed by capital floors and targeted investigations, the ECB has crafted a pragmatic middle ground that acknowledges both the technical complexity of model validation and the business reality that banks must adapt quickly to market conditions.
For banks, the reform promises faster approvals for material changes to internal models and reduced regulatory uncertainty. For supervisors, it promises more efficient resource allocation and enhanced focus on genuinely high-risk exposures. The reform forms part of the ECB’s agenda to streamline banking supervision while maintaining high supervisory standards and safeguarding resilience. Whether this balance holds will become apparent as banks begin implementing the new framework from 1 October 2026 onwards.