DBRS Morningstar Upgrades and Confirms Ratings on Tower Bridge Funding No. 4 PLC

DBRS Ratings Limited (DBRS Morningstar) took the following rating actions on the notes issued by Tower Bridge Funding No. 4 PLC (the Issuer):

-- Class A confirmed at AAA (sf)
-- Class B upgraded to AAA (sf) from AA (high) (sf)
-- Class C upgraded to AA (sf) from A (sf)
-- Class D upgraded to A (high) (sf) from BBB (high) (sf)
-- Class E upgraded to A (low) (sf) from BBB (low) (sf)
-- Class F upgraded to BB (high) (sf) from BB (sf)

The ratings on the Class A and Class B notes address the timely payment of interest and ultimate payment of principal on or before the legal final maturity date. The ratings on the Class C, Class D, Class E, and Class F notes address the ultimate payment of interest and principal on or before the legal final maturity date while junior, and timely payment of interest while the senior-most class outstanding.

The rating actions follow an annual review of the transaction and are based on the following analytical considerations:
-- Portfolio performance, in terms of delinquencies, defaults, and losses as of the March 2022 payment date.
-- Portfolio default rate (PD), loss given default (LGD), and expected loss assumptions on the remaining receivables.
-- Current available credit enhancement to the notes to cover the expected losses at their respective rating levels.

The transaction is a securitisation of mortgage loans originated by Belmont Green Finance Limited (BGFL), a specialist UK mortgage lender that offers a full suite of mortgage products including owner-occupied, buy-to-let, adverse-credit-history, and interest-only loans. The securitised mortgage portfolio comprises first-lien home loans originated by BGFL through its Vida Homeloans brand. BGFL is the named mortgage portfolio servicer but delegates its day-to-day servicing activities to Computershare Limited (formerly known as Homeloan Management Limited). The legal final maturity date is on the December 2062 payment date.

PORTFOLIO PERFORMANCE
As of the March 2022 payment date, loans two to three months in arrears represented 0.3% of the outstanding portfolio balance and the 90+ delinquency ratio was 1.5%, slightly up from 0.2% and 1.2%, respectively, at the last annual review. The cumulative loss ratio was zero.

PORTFOLIO ASSUMPTIONS AND KEY DRIVERS
DBRS Morningstar conducted a loan-by-loan analysis of the remaining pool of receivables and has decreased its base case PD and LGD assumptions to 5.1% and 21.3%, respectively, from 8.5% and 23.2%, respectively.

CREDIT ENHANCEMENT
Credit enhancement (CE) is provided by subordination of junior classes and the general reserve fund, and increased as follows since the last annual review as of the March 2022 payment date:
-- Class A to 29.3% from 23.5%
-- Class B to 21.3% from 17.1%
-- Class C to 15.0% from 12.0%
-- Class D to 11.2% from 8.9%
-- Class E to 8.8% from 7.0%
-- Class F to 6.7% from 5.4%

The transaction benefits from a reserve fund of GBP 12.5 million and a liquidity reserve fund of GBP 4.4 million. The liquidity reserve fund covers senior fees and interest on the Class A and Class B notes, while the general reserve fund covers senior fees, interest, and principal (via the principal deficiency ledgers) on the rated notes.

BNP Paribas Securities Services SCA, London Branch (BNPSS London) acts as the account bank for the transaction. Based on the DBRS Morningstar private rating of BNPSS London, the downgrade provisions outlined in the transaction documents, and other mitigating factors inherent in the transaction structure, DBRS Morningstar considers the risk arising from the exposure to the account bank to be consistent with the rating assigned to the Class A notes, as described in DBRS Morningstar's "Legal Criteria for European Structured Finance Transactions" methodology.

NatWest Markets Plc (NatWest Markets) acts as the swap counterparty for the transaction. DBRS Morningstar's public Long-Term Critical Obligations Rating of NatWest Markets at A (high) is above the First Rating Threshold as described in DBRS Morningstar's "Derivative Criteria for European Structured Finance Transactions" methodology.

DBRS Morningstar analysed the transaction structure in Intex DealMaker.

ESG CONSIDERATIONS
A description of how DBRS Morningstar considers ESG factors within the DBRS Morningstar analytical framework can be found in the DBRS Morningstar Criteria: Approach to Environmental, Social, and Governance Risk Factors in Credit Ratings at https://www.dbrsmorningstar.com/research/373262.

Notes:
All figures are in British pound sterling unless otherwise noted.

The principal methodology applicable to the ratings is: “Master European Structured Finance Surveillance Methodology” (8 February 2022).

Other methodologies referenced in this transaction are listed at the end of this press release. These may be found at: http://www.dbrsmorningstar.com/about/methodologies.

DBRS Morningstar has applied the principal methodology consistently and conducted a review of the transaction in accordance with the principal methodology.

A review of the transaction legal documents was not conducted as the legal documents have remained unchanged since the most recent rating action.

For a more detailed discussion of the sovereign risk impact on Structured Finance ratings, please refer to “Appendix C: The Impact of Sovereign Ratings on Other DBRS Morningstar Credit Ratings” of the “Global Methodology for Rating Sovereign Governments” at: https://www.dbrsmorningstar.com/research/381451/global-methodology-for-rating-sovereign-governments.

The DBRS Morningstar Sovereign group releases baseline macroeconomic scenarios for rated sovereigns. DBRS Morningstar analysis considered impacts consistent with the baseline scenarios as set forth in the following report: https://www.dbrsmorningstar.com/research/384482/baseline-macroeconomic-scenarios-application-to-credit-ratings.

The sources of data and information used for these ratings include loan-level data and investor reports provided by U.S. Bank Trustees Limited.

DBRS Morningstar did not rely upon third-party due diligence in order to conduct its analysis.

At the time of the initial rating, DBRS Morningstar was supplied with third-party assessments. However, this did not impact the rating analysis.

DBRS Morningstar considers the data and information available to it for the purposes of providing these ratings to be of satisfactory quality.

DBRS Morningstar does not audit or independently verify the data or information it receives in connection with the rating process.

The last rating action on this transaction took place on 9 July 2021, when DBRS Morningstar confirmed its ratings on the rated notes.

Information regarding DBRS Morningstar ratings, including definitions, policies, and methodologies, is available on www.dbrsmorningstar.com.

To assess the impact of changing the transaction parameters on the rating, DBRS Morningstar considered the following stress scenarios as compared with the parameters used to determine the rating (the Base Case):
-- DBRS Morningstar expected a lifetime base case PD and LGD for the pool based on a review of the current assets. Adverse changes to asset performance may cause stresses to base case assumptions and therefore have a negative effect on credit ratings.
-- The base case PD and LGD of the current pool of loans for the Issuer are 5.1% and 21.3%, respectively.
-- The risk sensitivity overview below illustrates the ratings expected if the PD and LGD increase by a certain percentage over the base case assumption. For example, if the LGD increases by 50%, the rating of the Class A Notes would be expected to remain at AAA (sf), assuming no change in the PD. If the PD increases by 50%, the rating of the Class A Notes would be expected to remain at AAA (sf), assuming no change in the LGD. Furthermore, if both the PD and LGD increase by 50%, the rating of the Class A Notes would be expected to remain at AAA (sf).

Class A Notes Risk Sensitivity:
-- 25% increase in LGD, expected rating of AAA (sf)
-- 50% increase in LGD, expected rating of AAA (sf)
-- 25% increase in PD, expected rating of AAA (sf)
-- 50% increase in PD, expected rating of AAA (sf)
-- 25% increase in PD and 25% increase in LGD, expected rating of AAA (sf)
-- 25% increase in PD and 50% increase in LGD, expected rating of AAA (sf)
-- 50% increase in PD and 25% increase in LGD, expected rating of AAA (sf)
-- 50% increase in PD and 50% increase in LGD, expected rating of AA (high) (sf)

Class B Notes Risk Sensitivity:
-- 25% increase in LGD, expected rating of AAA (sf)
-- 50% increase in LGD, expected rating of AAA (sf)
-- 25% increase in PD, expected rating of AAA (sf)
-- 50% increase in PD, expected rating of AAA (sf)
-- 25% increase in PD and 25% increase in LGD, expected rating of AAA (sf)
-- 25% increase in PD and 50% increase in LGD, expected rating of AA (high) (sf)
-- 50% increase in PD and 25% increase in LGD, expected rating of AA (sf)
-- 50% increase in PD and 50% increase in LGD, expected rating of AA (low) (sf)

Class C Notes Risk Sensitivity:
-- 25% increase in LGD, expected rating of AA (sf)
-- 50% increase in LGD, expected rating of AA (sf)
-- 25% increase in PD, expected rating of AA (sf)
-- 50% increase in PD, expected rating of AA (low) (sf)
-- 25% increase in PD and 25% increase in LGD, expected rating of AA (low) (sf)
-- 25% increase in PD and 50% increase in LGD, expected rating of A (high) (sf)
-- 50% increase in PD and 25% increase in LGD, expected rating of A (high) (sf)
-- 50% increase in PD and 50% increase in LGD, expected rating of A (low) (sf)

Class D Notes Risk Sensitivity:
-- 25% increase in LGD, expected rating of A (high) (sf)
-- 50% increase in LGD, expected rating of A (sf)
-- 25% increase in PD, expected rating of A (high) (sf)
-- 50% increase in PD, expected rating of A (sf)
-- 25% increase in PD and 25% increase in LGD, expected rating of A (sf)
-- 25% increase in PD and 50% increase in LGD, expected rating of A (low) (sf)
-- 50% increase in PD and 25% increase in LGD, expected rating of A (low) (sf)
-- 50% increase in PD and 50% increase in LGD, expected rating of BBB (high) (sf)

Class E Notes Risk Sensitivity:
-- 25% increase in LGD, expected rating of A (low) (sf)
-- 50% increase in LGD, expected rating of BBB (high) (sf)
-- 25% increase in PD, expected rating of A (low) (sf)
-- 50% increase in PD, expected rating of BBB (high) (sf)
-- 25% increase in PD and 25% increase in LGD, expected rating of BBB (high) (sf)
-- 25% increase in PD and 50% increase in LGD, expected rating of BBB (sf)
-- 50% increase in PD and 25% increase in LGD, expected rating of BBB (sf)
-- 50% increase in PD and 50% increase in LGD, expected rating of BBB (low) (sf)

Class F Notes Risk Sensitivity:
-- 25% increase in LGD, expected rating of BB (high) (sf)
-- 50% increase in LGD, expected rating of BB (high) (sf)
-- 25% increase in PD, expected rating of BB (high) (sf)
-- 50% increase in PD, expected rating of BB (sf)
-- 25% increase in PD and 25% increase in LGD, expected rating of BB (sf)
-- 25% increase in PD and 50% increase in LGD, expected rating of BB (low) (sf)
-- 50% increase in PD and 25% increase in LGD, expected rating of BB (low) (sf)
-- 50% increase in PD and 50% increase in LGD, expected rating of B (high) (sf)

For further information on DBRS Morningstar historical default rates published by the European Securities and Markets Authority (ESMA) in a central repository, see: http://cerep.esma.europa.eu/cerep-web/statistics/defaults.xhtml. DBRS Morningstar understands further information on DBRS Morningstar historical default rates may be published by the Financial Conduct Authority (FCA) on its webpage: https://www.fca.org.uk/firms/credit-rating-agencies.

These ratings are endorsed by DBRS Ratings GmbH for use in the European Union.

Lead Analyst: Natalia Coman, Assistant Vice President
Rating Committee Chair: Alfonso Candelas, Senior Vice President
Initial Rating Date: 24 June 2019

DBRS Ratings Limited
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London EC3M 3BY United Kingdom
Tel. +44 (0) 20 7855 6600
Registered and incorporated under the laws of England and Wales: Company No. 7139960

The rating methodologies used in the analysis of this transaction can be found at: http://www.dbrsmorningstar.com/about/methodologies.

--Master European Structured Finance Surveillance Methodology (8 February 2022), https://www.dbrsmorningstar.com/research/392000/master-european-structured-finance-surveillance-methodology
--European RMBS Insight Methodology (3 June 2021) and European RMBS Insight Model v5.4.3.2,
https://www.dbrsmorningstar.com/research/379557/european-rmbs-insight-methodology
--European RMBS Insight: UK Addendum (27 October 2021),
https://www.dbrsmorningstar.com/research/386599/european-rmbs-insight-uk-addendum
--Interest Rate Stresses for European Structured Finance Transactions (24 September 2021), https://www.dbrsmorningstar.com/research/384920/interest-rate-stresses-for-european-structured-finance-transactions
--Derivative Criteria for European Structured Finance Transactions (20 September 2021), https://www.dbrsmorningstar.com/research/384624/derivative-criteria-for-european-structured-finance-transactions
--Legal Criteria for European Structured Finance Transactions (29 July 2021), https://www.dbrsmorningstar.com/research/382171/legal-criteria-for-european-structured-finance-transactions
--Operational Risk Assessment for European Structured Finance Servicers (16 September 2021), https://www.dbrsmorningstar.com/research/384513/operational-risk-assessment-for-european-structured-finance-servicers
--DBRS Morningstar Criteria: Approach to Environmental, Social, and Governance Risk Factors in Credit Ratings (3 February 2021), https://www.dbrsmorningstar.com/research/373262/dbrs-morningstar-criteria-approach-to-environmental-social-and-governance-risk-factors-in-credit-ratings

A description of how DBRS Morningstar analyses structured finance transactions and how the methodologies are collectively applied can be found at: http://www.dbrsmorningstar.com/research/278375.

For more information on this credit or on this industry, visit www.dbrsmorningstar.com or contact us at [email protected].