UK banks face significant changes to regulatory capital requirements under the Basel 3.1 framework. The PRA’s recent release of PS9/24 provides more clarity, but also introduces new challenges for firms working to comply with these regulations.
As highlighted in our earlier analysis of PS9/24, this marks a key milestone in the UK's journey towards Basel 3.1 implementation. You can read our previous blog here for more on the initial release and its implications.
In this post, we’ll focus on the IRB part of the ruleset and outline the steps firms must take to ensure compliance by the 2026 deadline.
Basel 3.1 IRB update: What’s new
On September 12, 2024, the Prudential Regulation Authority (PRA) released PS9/24, which is the second part of the near-final rule set focusing on credit risk, the output floor and Pillar 3 disclosures.
The rules were published alongside supervisory statements on the Definition of Default (SS3/24) and Internal Ratings-Based (IRB) approaches (SS4/24). Additionally, the PRA released consultation papers on Pillar 2A, the definition of capital, the UK framework for capital buffers, and the strong and simple framework for small domestic deposit takers (SDDT).
Understanding the regulatory evolution
The transition to Basel 3.1 involves significant changes to the UK's regulatory framework. These changes affect multiple existing regulations and guidelines, creating a new structure that's more suited to the UK's post-EU regulatory environment.
The below diagram shows how the PRA Policy Statement PS9/24 consolidates various regulations, including the European Union CRR, Basel 3 Regulations, and the UK Technical Standards from PRA PS23/21. The new framework updates these requirements to create a unified UK approach.
[PRA Policy Statement PS9/24 and PRA Rulebook updates EU CRR for Basel 3 regulations and EU exit. Requirements for identification of a Downturn moved into PRA Rulebook]
The PRA Supervisory Statement SS3/24 represents a key change in how credit risk definition of default is managed. It combines and updates guidance from the EBA Guidelines on PD and LGD estimation with existing PRA requirements, particularly focusing on IRB approaches for mortgages.
[New PRA Supervisory Statement SS3/24 replaces and updates DoD EBA Guidelines EBA GL 2016/07 and SS11/13 Chapter 11 and part of Chapter 20]
SS4/24 brings together multiple sources of guidance on the UK’s IRB approach to credit risk. It consolidates EBA guidelines on PD and LGD estimation, including specific requirements for downturn conditions, with existing PRA supervisory statements.
[New PRA Supervisory Statement SS4/24 replaces and updates EBA Guidelines on PD and LGD (EBA GL 2017/16), downturn LGD (EBA 2019/03), and SS11/13]
PRA PS9/24: Key changes to the structure of the UK IRB regulations
Jaywing views the publication of PS9/24 as achieving two key goals: 1) to update existing regulations and guidelines to include the new Basel 3.1 requirements, and 2) to consolidate regulations and guidelines produced before the UK’s exit from the European Union.
Here are the primary structural changes:
Capital Requirements Regulation (CRR) will be replaced by the PRA Rulebook: The wording is contained in Appendix 2 of the PS9/24 release. This updates earlier versions of the rulebook shared with CP16/22 and PS17/23. The format of the new regulations is broadly similar to CRR, and article numbers have been kept consistent, with additional articles inserted as 143A, 143B etc.
SS4/24 replaces the existing IRB guidelines: Our assessment shows that SS4/24 is broadly a combination of the EBA guidelines on PD and LGD models (EBA GL 2017/16), downturn LGD models (EBA 2019/03) and SS11/13 (with relevant updates and additions for Basel 3.1). Some elements of SS11/13 – such as slotting criteria and risk weights – have now been excluded from SS4/24 but instead included in the PRA rulebook.
The identification of the nature, severity, and duration of an economic incorporated into the PRA Rulebook: The UK Regulatory Technical Standards (PS23/21), which was inherited from the EBA version EBA-RTS-2018-04 (in draft at the time of the EU exit), has now been included in the PRA near final rulebook as Articles 181A, 181B and 181C.
Language and nomenclature revisions: The revised statements use more “typical” PRA language (e.g. “the PRA expects that ….”, “firms” in SS4/24 instead of “institutions” in EBA guidelines), and replace thresholds (e.g. retail) with £ denominated amounts broadly equivalent to the Euro amounts used by EBA.
PRA PS9/24: Key changes to the UK IRB rules
PS9/24 is Part 2 of the “near final rules”, following the significant changes from the existing regulations and guidance defined in Part 1 (PS17/23). The rules will become “final” following implementation into UK Law by HM Treasury.
The ability to use the IRB approach has been removed or amended for larger, low volume exposures such as sovereigns and large corporates.
For smaller, high-volume exposures i.e. retail, specialised lending and smaller corporates, the regulations still present challenges to firms to comply before the deadline of 1 January 2026 however the PRA have allowed for material compliance, with the rollout plan.
New “input floors” for PD, EAD and LGD:
- For PD, the “blanket” 0.03% floor has been raised to 0.1% for QRRE non-transactors and residential mortgages, and 0.05% for all other retail exposures.
- The requirements for 5% account level and 10% exposure weighted portfolio level LGD floors for mortgages have been retained but moved from SS to regulation.
- LGD floors of 50% for QRRE (both transactors and revolvers) and 30% for other unsecured retail have been introduced.
- For EAD, conversion factor floors of 50% of standardised / foundation values have been introduced for modelled EADs for revolving balances.
New “output floor” as laid out in the PRA Rulebook article 92: 72.5% of standardised RWA, adjusting for differences in the treatment of accounting provisions. The treatment of accounting provisions was changed following consultation CP6/22 (PS9/24 5.13 – 5.21).
Additionally, firms need to migrate their existing attestation documents to the new regulations. This process will involve identifying changes and areas where requirements remain similar or unchanged.
Basel 3.1 IRB updates: What firms should do next
Given that firms will likely have already considered the required changes outlined in consultation paper CP16/22, we recommend updating their assessments and plans to reflect the “near-final” regulations. We would expect that this would follow several key steps:
- Conduct a gap analysis - identify changes to rules e.g. those that impact capital, implementation or reporting
- Assess the capital impact
- Evaluate compliance impacts
- Review of capital strategy and stress testing framework
These steps help to ensure firms are fully prepared to meet the new regulatory requirements on time, minimising risk and optimising their capital strategy in line with the updated Basel 3.1 framework.
How Jaywing’s regulatory risk experts can help
Jaywing’s regulatory risk team are experts in all aspects of IRB modelling and compliance. We can guide you through every step of the process, ensuring your institution is fully prepared for the 2026 deadline. Our comprehensive services include:
- Strategic impact analysis: We help you understand what these changes mean for your business model and regulatory capital strategy, identifying potential risks and opportunities specific to your firm.
- Model redevelopment or validation: our modelling experts can advise on how to update models or provide independent model validation of changes made.
- Compliance assurance: Our team ensures you meet all regulatory requirements. We'll work closely with your compliance, risk, and finance departments to develop and implement robust processes that align with the new Basel 3.1 standards.
- Implementation and testing support: We assist in implementing and rigorously testing changes to your data management systems, reporting frameworks, and regulatory processes. Our approach minimises disruption and maximises efficiency.
By partnering with Jaywing, you gain access to our deep regulatory risk knowledge and proven methodologies.
Contact us today to discuss how we can tailor our services to your specific needs and ensure your institution is fully prepared.