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Risk and prudential glossary

RiskTAE’s risk and prudential glossary gives plain-English definitions of the capital, liquidity, resolution and governance terms that risk leaders at UK banks and building societies use. Each definition is drawn from its primary source (the PRA Rulebook, a PRA or Bank of England policy document, or a Basel Committee text) and links to our page on the subject where we have one.

B

Basel 3.1
The PRA’s name for the final Basel III reforms to how banks measure risk-weighted assets. The UK’s final rules were published in PS1/26 on 20 January 2026 and apply from 1 January 2027, apart from the internal model approach for market risk, which follows on 1 January 2028. Explained: what Basel 3.1 changes for UK banks. Help: Basel 3.1 implementation support.
Business Indicator (BI)
The measure of size behind Pillar 1 operational risk capital from 1 January 2027: the sum of the interest, leases and dividend component, the services component and the financial component, each averaged over three years (Operational Risk Part rules 5.2 to 5.4). The PRA sets the Internal Loss Multiplier to one, so the Business Indicator Component is the requirement. Explained: how to calculate it. Help: operational risk capital.

C

Capital conservation buffer
A buffer of CET1 capital equal to 2.5% of a firm’s total risk exposure amount (Capital Buffers 2.1).
CET1 ratio
Common equity tier 1 capital as a percentage of a firm’s total risk exposure amount. The Pillar 1 minimum is 4.5% (Article 92).
Collective rebuttal
A Basel Committee term for a clearly enforceable law or regulation of general application that explicitly prohibits a bank from supporting an entity, which lets the bank exclude that entity from its step-in risk assessment. The PRA does not accept it as a ground for exclusion and treats such prohibitions as mitigants instead. Help: how the PRA treats prohibitions on support.
Combined buffer
The sum of a firm’s capital conservation buffer and countercyclical capital buffer, plus any G-SII or O-SII buffer that applies to a global or other systemically important institution.
Conversion approach
A way of estimating a firm’s exposure to a step-in entity by applying a conversion factor to that entity’s assets. It is one of the responses in the Basel Committee’s 2017 step-in risk guidelines and in the PRA’s SS1/25. Help: estimating step-in exposures.
Conversion factor (CF)
The percentage of an off-balance-sheet commitment that is treated as a credit exposure. Under the Basel 3.1 standardised approach, transaction-related contingent items take 20% and other commitments 40%, except UK residential mortgage commitments. Help: re-weighting commitments for Basel 3.1.
Countercyclical capital buffer (CCyB)
A buffer of CET1 capital whose rate the Financial Policy Committee sets to reflect risks in the credit cycle.
Credit risk mitigation (CRM)
The recognition of collateral, guarantees and credit derivatives that reduce the capital a firm holds for credit risk. Basel 3.1 changes the treatment of funded and unfunded credit protection. Help: credit risk mitigation under Basel 3.1.
CVA risk
The risk of losses from changes in credit valuation adjustments on derivatives and securities financing transactions. Under Basel 3.1 it is capitalised with the alternative (AA-CVA), basic (BA-CVA) or standardised (SA-CVA) approach, and the SDDT regime disapplies CVA risk capital. Help: CVA risk under Basel 3.1.

F

Fitness and propriety
The test a firm applies before asking the PRA to approve a senior manager: personal characteristics including good repute and integrity, competence, knowledge and experience, qualifications and training (Fitness and Propriety rules 2.1 and 2.6). Explained: how long SMF4 approval takes.
Fractional chief risk officer
A chief risk officer who holds the role part time on a continuing basis. A fractional CRO who performs SMF4 needs PRA approval before starting, in the same way as a full-time one (Senior Management Functions Part). Explained: interim or fractional CRO. Help: fractional chief risk officers.
FRTB
The Fundamental Review of the Trading Book, the market risk framework within Basel 3.1. Its new standardised approaches and revised trading book boundary apply from 1 January 2027, and its new internal model approach from 1 January 2028. Explained: FRTB in the UK, 2027 and 2028. Help: FRTB implementation support.

I

ICAAP
The internal capital adequacy assessment process: a firm’s own ongoing assessment of the capital it needs for the risks it faces, including stress testing. The PRA sets out its expectations in SS31/15. SS4/25’s expectations on how often an SDDT updates its ICAAP have applied since 20 January 2026; the rest of SS4/25 replaces SS31/15 for SDDTs from 1 January 2027 (PS4/26 paragraph 1.16). Explained: what an ICAAP is. Help: ICAAP writing and review.
ICARA
The internal capital adequacy and risk assessment process that an FCA investment firm under MIFIDPRU must operate to identify and monitor the material harms its business could cause, and to hold own funds and liquid assets adequate to cover them and to wind down in an orderly way (MIFIDPRU 7.4.7R and 7.4.9R). The firm reviews it at least once every 12 months and records the result in its ICARA document (MIFIDPRU 7.8.2R and 7.8.7R). Explained: what an ICARA is. Help: ICARA writing and review.
ILAAP
The internal liquidity adequacy assessment process: a firm’s process for identifying, measuring, managing and monitoring its liquidity. SDDTs use a simpler ILAAP template and generally face no Pillar 2 liquidity add-ons. The PRA consulted on changes to SS24/15 and SoP1/18 in CP5/26 (March 2026). Explained: ICAAP vs ILAAP. Help: ILAAP writing and review.
IMA, ASA and SSA
The internal model approach, advanced standardised approach and simplified standardised approach to market risk capital under FRTB. The ASA or SSA applies from 1 January 2027, firms with existing IMA permissions may keep them for that interim year, and the new IMA starts on 1 January 2028. Explained: which market risk approach applies when. Help: choosing a market risk approach.
Impact tolerance
The maximum tolerable level of disruption to an important business service (Operational Resilience Part). Explained: what a head of non-financial risk does. Help: operational resilience leadership search.
Important business service
A service a firm provides which, if disrupted, could threaten the firm’s safety and soundness or, for O-SIIs, UK financial stability (Operational Resilience Part). Explained: what a head of non-financial risk does. Help: operational resilience leadership search.
Individual liquidity guidance (ILG)
The firm-specific guidance the PRA gives after its liquidity supervisory review (L-SREP) on the amount and quality of high-quality liquid assets it considers appropriate, including for liquidity risks the LCR does not capture. The PRA expects firms not to disclose their total ILG publicly (SS24/15). Explained: what an ILAAP is. Help: ILAAP writing and review.
Input floors
Minimum values for PD, LGD and EAD that firms must use in IRB models under Basel 3.1. PS1/26 corrected the retail LGD floor for the unsecured portion of a partially secured exposure to 30%. Help: IRB model changes under Basel 3.1.
Interim Capital Regime (ICR)
A planned opt-in regime, first proposed in CP16/22 as the Transitional Capital Regime, that would have let SDDT-eligible firms keep their existing capital requirements until the SDDT capital regime began. Once Basel 3.1 and the SDDT regime were aligned on 1 January 2027 it was no longer needed, and its rules were revoked on 20 January 2026 without ever taking effect. Help: where SDDT-eligible firms stand now.
Interim chief risk officer
A chief risk officer appointed for a fixed period, usually to cover a vacancy while a permanent appointment is made. The interim performs SMF4 and needs PRA approval unless the firm can rely on the 12-week rule, which covers an employee of the firm standing in for an absence that is temporary or reasonably unforeseen (Senior Management Functions rule 2.3). Explained: interim or fractional CRO. Help: interim chief risk officers.
Internal Loss Multiplier (ILM)
A scaling factor in the standardised approach for operational risk, based on a firm’s historical losses. The PRA sets it equal to one, so loss history does not change a UK firm’s Pillar 1 operational risk capital. Explained: the Business Indicator calculation. Help: operational risk capital.
Internal ratings based approach (IRB)
Approaches that let a firm with PRA permission use its own estimates in credit risk capital: under foundation IRB (FIRB) it estimates PD, and under advanced IRB (AIRB) it also estimates LGD and EAD. Basel 3.1 removes IRB for central governments, central banks and equity, and removes AIRB for institutions, financial corporates and large corporates (annual revenue over £440 million on a three-year average). Help: IRB scope changes under Basel 3.1.
International subsidiary approach
A PRA permission under which certain UK subsidiaries of overseas groups use un-floored RWAs at UK consolidated level, leaving the output floor to apply at group level abroad. It is not open to ring-fenced bodies, and one condition is that the home jurisdiction has made specific and public proposals to implement the output floor. Explained: the output floor for UK subsidiaries.
Investment grade (unrated corporates)
Under the Basel 3.1 standardised approach, a firm with PRA permission can give an unrated corporate it assesses as investment grade a 65% risk weight and other unrated corporates 135%. Without that permission the default for unrated corporates is 100%. Help: corporate risk weights under Basel 3.1.
IPRE and HVCRE
Income-producing real estate and high-volatility commercial real estate, two sub-classes of specialised lending. From 1 January 2027, IPRE exposures under FIRB or AIRB move to the standardised approach unless the firm applies to use slotting. Help: real estate lending under Basel 3.1.
IRRBB
Interest rate risk in the banking book. SS31/15 names it as one of the risks the PRA assesses for Pillar 2A. Help: IRRBB in the ICAAP.

L

Leverage ratio
Tier 1 capital divided by a firm’s total exposure measure, expressed as a percentage (Leverage Ratio (CRR) Part, Article 429(2)).
Liquidity coverage ratio (LCR)
A firm’s liquidity buffer divided by its net liquidity outflows over a 30-day stress period, which must be at least 100%.
Loan-splitting
The UK Basel 3.1 treatment of residential mortgages that are not materially dependent on cash flows from the property: the part of the loan up to 55% of the property value takes a 20% risk weight, and the rest takes the counterparty’s risk weight (Article 124F). Help: mortgage risk weights under Basel 3.1.

M

Material outsourcing
Outsourcing so important that a failure in it would cast serious doubt on the firm continuing to meet its threshold conditions or the Fundamental Rules (PRA Glossary). Suppliers under material outsourcing arrangements count as unconsolidated entities for step-in risk. Explained: what a head of non-financial risk does. Help: third-party risk leadership search.
Materially dependent on cash flows
Real estate lending where repayment relies on income from the property, which attracts higher risk weights under Basel 3.1. Firms must assess all existing real estate exposures for material dependence by 1 January 2027. Help: the material dependence assessment.
Maximum distributable amount (MDA)
A rule-based cap on distributions that a firm must calculate when it does not meet its combined buffer (Capital Buffers 4.3). The Single Capital Buffer for SDDTs removes automatic MDA restrictions.
MREL
The minimum requirement for own funds and eligible liabilities, which the Bank of England sets so that a firm can be resolved.

N

Net stable funding ratio (NSFR)
Available stable funding divided by required stable funding, which must be at least 100% (Article 428b). An SDDT with a high enough retail deposit ratio can meet stable funding standards without monitoring it.

O

Off-cycle review
The PRA’s one-off recalibration of firm-specific Pillar 2 capital to remove double counting between Pillar 1 and Pillar 2A arising from Basel 3.1. It also rebases variable Pillar 2A and the PRA buffer, and firms do not need to produce a full ICAAP for it. Help: the off-cycle review and your ICAAP.
Operational risk
In the Basel Committee’s words, “the risk of loss resulting from inadequate or failed internal processes, people and systems or from external events.” Under Basel 3.1 a single standardised approach replaces the existing approaches to its Pillar 1 capital. Explained: how the Business Indicator works. Help: operational risk capital under Basel 3.1.
ORSA
The own risk and solvency assessment a UK Solvency II insurer must conduct as part of its risk-management system: its overall solvency needs given its risk profile, its continuous compliance with the SCR, the MCR and the technical provisions requirements, and how far its risk profile departs from the assumptions behind the SCR. It is run regularly and without delay after any significant change in risk profile, and the results go to the PRA in an ORSA report (Conditions Governing Business 3.8 to 3.11). Explained: what an ORSA is. Help: ORSA support.
Output floor
A limit that stops a firm’s modelled RWAs falling below 72.5% of the RWAs it would calculate using standardised approaches alone. In the UK it phases in at 60% in 2027, 65% in 2028 and 70% in 2029, reaching 72.5% on 1 January 2030. Explained: how the output floor works. Help: the output floor in your capital plan.
Overall financial adequacy rule
The PRA rule that a firm must at all times hold enough financial resources for its liabilities to be met as they fall due (Internal Capital Adequacy Assessment Part 2.1).

P

PD, LGD and EAD
Probability of default, loss given default and exposure at default, the main inputs to IRB credit risk models. PS1/26 moves the definitions of PD, LGD and conversion factor into the PRA Rulebook Glossary. Help: IRB parameters under Basel 3.1.
Pillar 1
The minimum own funds requirements that rules set for every firm. Under Basel 3.1 they cover credit, market, CVA and operational risk, subject to the output floor.
Pillar 2A
Firm-specific capital the PRA requires above Pillar 1 for risks that Pillar 1 does not capture, or captures only in part. The PRA sets it through the SREP. Explained: Pillar 2A explained. Help: Pillar 2A in your ICAAP.
Pillar 2B
Capital for the risks a firm may face over a forward-looking horizon, including under stress (SS31/15). Explained: the PRA buffer and Pillar 2B. Help: stress testing for Pillar 2B.
Pillar 3
The public disclosure requirements on a firm’s capital, risks and RWAs. PS1/26 sets out updated Pillar 3 templates for Basel 3.1. Help: Basel 3.1 disclosures.
PLAT and NMRF
The profit and loss attribution test and non-modellable risk factors, two elements of the FRTB internal model approach. The PRA consulted on changes to both in CP9/26, published on 19 June 2026. Explained: the FRTB internal model approach.
PRA buffer
A firm-specific capital buffer the PRA sets above the Total Capital Requirement and the combined buffer, sized so the firm can withstand a stress. For SDDTs the Single Capital Buffer replaces it from 1 January 2027. Explained: how the PRA buffer is set. Help: the PRA buffer in your capital plan.
Preferred resolution strategy
The Bank of England’s planned approach to resolving a failing firm: bail-in, transfer or modified insolvency. The Bank’s MREL statement of policy says firms with more than £40 billion of total assets should expect bail-in.

R

Recovery plan
A firm’s plan of the measures it could take to restore its financial position after a significant deterioration (Recovery Plans Part 2.2). Help: recovery planning advisory; RisKIT recovery planning models.
Refined methodology
A Pillar 2A credit risk offset that the PRA retires for all firms from 1 January 2027 (PS2/26). Help: replacing the refined methodology.
Regulatory reference
An employment reference in a mandatory template, covering a candidate’s conduct and fitness and propriety over the previous six years, that firms must request for senior manager, certification and notified non-executive appointments (Fitness and Propriety rules 2.7 and 5.1; SS28/15 chapter 6). Explained: regulatory references after PS12/26.
Residual risk add-on (RRAO)
An add-on within the FRTB advanced standardised approach. UK firms can apply for a permission where it is disproportionate, and permission holders should reflect relevant changes in their Pillar 2A calculation. Explained: the FRTB standardised approach.
Retail deposit ratio (RDR)
A measure of an SDDT’s retail funding. An SDDT whose four-quarter moving average RDR is above 50% for four consecutive quarters can meet stable funding standards without monitoring the NSFR (PS15/23). Help: SDDT liquidity simplifications.
Reverse stress test
A test that runs a firm’s business plan to failure to find the scenarios that would make it unviable (Internal Capital Adequacy Assessment Part). For SDDTs, PS4/26 changed how often it must be run, with effect from 20 January 2026. Help: reverse stress testing in the ICAAP.
Risk-weighted assets (RWAs)
A firm’s exposures adjusted for their risk, which form the denominator of its risk-based capital ratios. Basel 3.1 changes how they are measured. Help: recalculating RWAs for Basel 3.1.

S

SCRA
The standardised credit risk assessment approach, which grades unrated bank exposures A, B or C for risk-weighting under the Basel 3.1 standardised approach. Help: bank exposure risk weights under Basel 3.1.
SDDT
A small domestic deposit taker: a UK bank or building society that meets the PRA’s SDDT criteria and has accepted the PRA’s modification to join the regime. The criteria include average total assets of no more than £20 billion, a 36-month average of at least 85% of relevant credit exposures in the UK, and no use of IRB. Check: SDDT eligibility checker. Help: SDDT regime support.
Single Capital Buffer (SCB)
One non-cyclical capital buffer for SDDTs that replaces the capital conservation buffer, the CCyB and the PRA buffer from 1 January 2027, without automatic MDA restrictions. The PRA will set it at no lower than 3.5% of RWAs (SoP5/25, paragraph 12.11), and each firm’s own figure is confidential. Help: the Single Capital Buffer in your capital plan.
Skilled person review
A report the PRA or the FCA requires under section 166 of FSMA from an independent expert on a matter concerning a regulated firm, normally at the firm’s cost. The PRA’s policy is in SS7/14. Explained: how a section 166 review works. Help: skilled person review support.
SME and infrastructure lending adjustments
Firm-specific Pillar 2A adjustments that replace the SME and infrastructure support factors removed from Pillar 1 under Basel 3.1, so that removing them does not increase overall capital requirements (PS7/25). Help: SME and infrastructure lending under Basel 3.1.
SMF1, SMF2 and SMF24
The Chief Executive, Chief Finance and Chief Operations functions in the PRA’s Senior Management Functions Part.
SMF4
The Chief Risk function: responsibility for the overall management of a firm’s risk controls and for reporting to the board on risk (PRA Senior Management Functions Part). Explained: what a chief risk officer does. Help: chief risk officer search.
SMF5 and SMF9
The Head of Internal Audit function and the Chair of the Governing Body function in the PRA’s Senior Management Functions Part.
SMF10
The Chair of Risk Committee function in the PRA’s Senior Management Functions Part. Explained: appointing a risk committee chair. Help: risk committee chair search.
Solvent exit
The process by which a firm stops carrying on PRA-regulated activities while remaining solvent. SS2/24 sets out the PRA’s expectations for solvent exit planning by non-systemic banks and building societies. Help: wind-down and solvent exit planning.
SoP5/25
The PRA’s statement of policy on its methodologies for setting Pillar 2 capital for SDDTs, effective from 1 January 2027. It includes the Single Capital Buffer, which the PRA will set at no lower than 3.5% of each SDDT’s RWAs (paragraph 12.11). Explained: whether your bank should join the SDDT regime. Help: SDDT regime support.
Specialised lending and slotting
Specialised lending covers project finance, object finance, commodities finance and income-producing real estate, which IRB firms may risk-weight using supervisory slotting categories. Basel 3.1 cuts the slotting risk weight for “substantially stronger” project finance to 50%. Help: slotting under Basel 3.1.
SREP
The supervisory review and evaluation process: the PRA’s review of a firm’s ICAAP and risks, which it uses to set the firm’s Pillar 2 capital. Explained: how the PRA uses the ICAAP. Help: preparing the ICAAP for the SREP.
SS4/25
The PRA’s supervisory statement on the ICAAP and the SREP for SDDTs. Its expectations on how often an SDDT updates its ICAAP have applied since 20 January 2026, and it takes effect as a whole on 1 January 2027, when SDDTs leave the scope of SS31/15 (PS4/26 paragraph 1.16). Explained: SS4/25 and the SDDT ICAAP. Help: ICAAP writing and review.
SSPE
A securitisation special purpose entity. SSPEs are named in the PRA Glossary as unconsolidated entities for step-in risk, but a firm need not identify one where it holds only a senior position and is not the original lender, originator or sponsor (Step-in Risk 6.2). Help: securitisation vehicles and step-in risk.
Standardised approach for credit risk (SA-CR)
Risk weights set by the regulator for credit exposures, which Basel 3.1 makes more risk-sensitive for residential mortgages, corporates and SMEs, among others. It also requires firms to revalue a property when they estimate its value has fallen by more than 10% since the last valuation. Help: the Basel 3.1 standardised approach.
Standardised approach for operational risk
The single Basel 3.1 approach to operational risk capital, which replaces the existing approaches. It multiplies the Business Indicator, a proxy taken from the financial statements, by marginal coefficients of 12% up to £0.88bn, 15% from £0.88bn to £26bn and 18% above £26bn to give the Business Indicator Component (BIC). Explained: worked Business Indicator examples. Help: operational risk capital.
Standardised Measurement Approach (SMA)
The name the Basel Committee used in its consultation of 4 March 2016 for what became the standardised approach for operational risk. Help: the UK standardised approach for operational risk.
Statement of responsibilities
The document that goes with every application for a senior manager and sets out the responsibilities allocated to that person. A firm keeps a complete, current set for everyone approved to perform a PRA senior management function (Allocation of Responsibilities rules 2.1 and 2.4). Explained: matching it to a CRO job description.
Step-in entity
An unconsolidated entity that a firm must identify under Step-in Risk 6.1(1), for example because it sponsors the entity or invests in it. A step-in entity is immaterial if support to it would not materially affect the firm’s capital or liquidity, and material otherwise. Help: identifying step-in entities.
Step-in risk
The risk that a firm provides financial support to a step-in entity in stressed conditions, without or beyond any contractual obligation to do so. In the UK the Step-in Risk Part of the PRA Rulebook and SS1/25 have applied since 1 January 2026 to firms that are not SDDTs. Help: step-in risk assessments.
Step-in sponsor
A firm that manages or advises an unconsolidated entity, places its securities, or provides it with liquidity or credit enhancement (Step-in Risk 1.2). Help: sponsor relationships and step-in risk.
Strong and Simple Framework
The PRA’s initiative to build a simpler prudential regime for small domestic deposit takers. Its capital regime, set out in PS4/26 on 20 January 2026, takes effect on 1 January 2027. Explained: whether your bank should join. Help: strong and simple regime support.

T

Tier 1 and total capital ratios
Tier 1 capital and total capital, each as a percentage of total risk exposure amount. The Pillar 1 minimums are 6% and 8% respectively (Article 92).
Total Capital Requirement (TCR)
Pillar 1 plus Pillar 2A capital requirements, as the term is used in SS31/15. It shares its initials with the Transitional Capital Regime, the 2022 name for what became the Interim Capital Regime. Help: the TCR in your capital plan.
Total risk exposure amount (TREA)
The RWA figure a firm uses for its capital ratios, including any uplift from the output floor. Under Basel 3.1 it is the higher of U-TREA and the floor, which is a set percentage of S-TREA plus an adjustment for accounting provisions (Article 92(2A)). Explained: TREA under the output floor.
Twelve-week rule
The rule that lets a firm appoint an employee to cover a senior management function without approval for less than 12 weeks in a consecutive 12-month period, where the absence is temporary or reasonably unforeseen (Senior Management Functions rules 2.3 to 2.3B). Since 24 April 2026, where the absence was reasonably unforeseen, the cover can continue until a valid and complete application made within that period is decided. Explained: how the 12-week rule works.

U

U-TREA and S-TREA
U-TREA is a firm’s un-floored RWAs using the approaches it has approval for; S-TREA is the same exposures recalculated using standardised approaches only. The output floor compares the two. Explained: U-TREA and S-TREA in the output floor. Help: running both calculations.
Unconsolidated entity
An undertaking outside a firm’s regulatory consolidation, such as an SSPE, an asset management company or a supplier under a material outsourcing arrangement (PRA Glossary). Help: mapping unconsolidated entities.

W

Wind-down plan
A firm’s plan for ceasing its regulated activities in an orderly way. The FCA’s Wind-down Planning Guide says an effective plan aims to let a firm do so with “minimal adverse impact on its clients, counterparties or the wider markets”, and helps it check it has adequate capital, liquidity, knowledge and manpower to wind down (WDPG 1.1.1 and 1.1.2). Explained: wind-down plan template. Help: wind-down and solvent exit planning.

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