Updated MREL levels for Banco Santander (BCDRF) after SRB decision

Rhea-AI Filing Summary

Banco Santander, S.A. reports that Banco de España has notified new binding minimum requirements for own funds and eligible liabilities (MREL) for the resolution group headed by Banco Santander, replacing the prior framework. The new Total MREL is 31.17% of total risk‑weighted assets and 11.86% of leverage ratio exposure, while Subordinated MREL is 11.56% and 6.11%, respectively. The applicable Combined Buffer Requirement on risk‑weighted assets is 4.42%, so Total MREL plus this buffer is 35.59%. As of 31 December 2025, the group’s own funds and eligible liabilities structure meets both Total and Subordinated MREL requirements.

Key Figures

Total MREL (TREA): 31.17% Total MREL (LRE): 11.86% Subordinated MREL (TREA): 11.56% +3 more

6 metrics

Total MREL (TREA) 31.17% New requirement as percentage of total risk-weighted assets

Total MREL (LRE) 11.86% New requirement as percentage of leverage ratio exposure

Subordinated MREL (TREA) 11.56% New subordinated requirement based on total risk-weighted assets

Subordinated MREL (LRE) 6.11% New subordinated requirement based on leverage exposure

Combined Buffer Requirement 4.42% Capital buffer applied on TREA; added to Total MREL

Total MREL + buffer (TREA) 35.59% Total MREL plus Combined Capital Buffer requirement

Key Terms

MREL, Subordinated MREL, Total Risk Exposure Amount, Leverage Ratio Exposure, +2 more

6 terms

MREL financial

"new binding minimum requirement for own funds and eligible liabilities (“MREL”), both total and subordinated"

Minimum Requirement for own funds and Eligible Liabilities (MREL) is a regulatory standard that forces banks to hold a buffer of capital and debt that can absorb losses or be written down if the bank fails. Think of it like a combined savings account and emergency loan line that regulators require so creditors and investors, rather than taxpayers, bear the cost when a bank gets into trouble. For investors, MREL influences how risky a bank’s bonds and shares appear and can affect debt pricing, recovery prospects in a failure, and the bank’s capacity to lend or return capital.

Subordinated MREL financial

"a requirement which must be met through own funds and subordinated eligible liabilities (“Subordinated MREL”) has been determined"

Total Risk Exposure Amount financial

"percentage of the Resolution Group’s total risk-weighted assets (Total Risk Exposure Amount, “TREA”)"

Leverage Ratio Exposure financial

"and of leverage exposure (Leverage Ratio Exposure, “LRE”) as of 31 December 2024"

Combined Buffer Requirement financial

"do not include the applicable Combined Buffer Requirement. The Combined Buffer Requirement, applicable to the TREA"

Alternative Performance Measures financial

"this document includes certain Alternative Performance Measures (APMs), as defined in the Guidelines on Alternative Performance Measures"

Alternative performance measures are financial figures companies present alongside official accounting numbers that strip out certain costs or gains to highlight how management views underlying business trends. Think of it like a cook showing a recipe’s calories without the sauce to emphasize the main ingredients; investors use these adjusted numbers to compare performance and spot trends, but they can vary by company and require careful scrutiny to avoid misleading comparisons.

Form 6-K: How Foreign Companies Report to the SEC →

FORM 6-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

For the month of April, 2026

Commission File Number: 001-12518

Banco Santander, S.A.

(Exact name of registrant as specified in its charter)

Ciudad Grupo Santander

28660 Boadilla del Monte (Madrid) Spain

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F X Form 40-F

Banco Santander, S.A.

TABLE OF CONTENTS

Item
1	Report of Other Relevant Information dated April 14, 2026

Banco Santander, S.A. (“Banco Santander”), in compliance with the Securities Market legislation, hereby announces:

OTHER RELEVANT INFORMATION

Banco de España has formally notified the new binding minimum requirement for own funds and eligible liabilities (“MREL”), both total and subordinated, for the resolution group headed by Banco Santander¹ (the “Resolution Group”), which has been determined by the Single Resolution Board (“SRB”) and is applicable upon receipt of the notification. This notification (the “current notification”) replaces and supersedes the previously applicable notification which was announced as other relevant information on 7 May 2025 (CNMV registration number 34598) (the “former notification”).

The MREL requirement (“Total MREL”) is expressed as a percentage of the Resolution Group’s total risk-weighted assets (Total Risk Exposure Amount, “TREA”) and of leverage exposure (Leverage Ratio Exposure, “LRE”) as of 31 December 2024. Within this Total MREL, a requirement which must be met through own funds and subordinated eligible liabilities (“Subordinated MREL”) has been determined.

In accordance with the current notification, the Resolution Group must comply with the following MREL requirements².

	Requirement in terms of ‘TREA’ (Total Risk-Weighted Assets)		Own funds and eligible liabilities in terms of ‘TREA’
	New requirement	Requirement prior to notification	As of 31 December 2025
Total MREL	31.17%	31.92%	39.73%
Subordinated MREL	11.56%	10.95%	34.04%

	Requirement in terms of ‘LRE’ (Leverage Ratio Exposure)		Own funds and eligible liabilities in terms of ‘LRE’
	New requirement	Requirement prior to notification	As of 31 December 2025
Total MREL	11.86%	12.75%	15.25%
Subordinated MREL	6.11%	6.27%	13.06%

The Total MREL requirement and the Subordinated MREL requirement in terms of TREA do not include the applicable Combined Buffer Requirement. The Combined Buffer Requirement, applicable to the TREA in accordance with the applicable regulation and the supervisory criteria, is currently 4.42%. Total MREL requirement in terms of TREA plus the Combined Capital Buffer is 35.59%.

As of 31 December 2025, the structure of own funds and eligible liabilities of the Resolution Group meets the requirements of Total MREL and Subordinated MREL³.

Boadilla del Monte (Madrid), 14 April 2026

¹ In accordance with the Multiple Point of Entry (“MPE”) resolution strategy of Grupo Santander as determined by the SRB: 

- the Resolution Group is composed of Banco Santander and its relevant subsidiaries belonging to the same resolution group, mainly the entities of the sub-groups headed by Santander Consumer Finance, S.A., Open Bank, S.A. and Santander Totta SGPS, S.A. (the “Resolution Group”); and

- a portion of the MREL requirement is calculated based on the intragroup exposures between the Resolution Group and the other resolution groups of Grupo Santander.

² The Total MREL requirement has been determined by the SRB considering (i) a downward adjustment of 20% of the market confidence charge (“MCC”), according to Article 12d(3) of Regulation (EU) 806/2014 and the SRB 2024 MREL Policy, (ii) an adjusted regime related to holdings of eligible liabilities instruments applicable to 50% of Banco Santander México, S.A. (which does not belong to the Resolution Group), in accordance with articles 72e(4) and 477a of Regulation (EU) 575/2013, and (iii) the completion of the sale of 49% of the share capital of Santander Bank Polska S.A. to Erste Group Bank AG. Factors (i) and (ii) were already considered for the requirement prior to the current notification, while factor (iii) has been incorporated into the new requirement.

³ As of 31 December 2025, with 11 resolution groups:

- The TREA total amount of the Resolution Group was EUR 425,530 million; and

- The LRE total amount of the Resolution Group was EUR 1,108,944 million.

IMPORTANT INFORMATION

Non-IFRS Financial Indicators and Alternative Performance Measures

In addition to the financial information prepared in accordance with the International Financial Reporting Standards (IFRS) and derived from our financial statements, this document includes certain Alternative Performance Measures (APMs), as defined in the Guidelines on Alternative Performance Measures published by the European Securities and Markets Authority (ESMA) on October 5, 2015, as well as certain non-IFRS financial indicators. The financial measures contained in this consolidated management report that are considered APMs and non-IFRS financial indicators have been prepared based on the financial information of Grupo Santander but are not defined or detailed within the applicable financial reporting framework and have not been audited or reviewed by our auditors.

We use these APMs and non-IFRS financial indicators to plan, monitor, and assess our performance.

We believe that these APMs and non-IFRS financial indicators are useful in enabling the management team and investors to compare operational performance across periods.

However, these APMs and non-IFRS financial indicators are considered supplementary information and are not intended to replace IFRS measures. Furthermore, other companies, including some in our sector, may calculate such measures differently, which reduces their usefulness for comparative purposes. APMs that use sustainability-related designations are not calculated in accordance with the Taxonomy Regulation or the SFDR adverse impact indicators. For more information on the APMs and non-IFRS financial indicators used, including their definition or a reconciliation between the applicable management indicators and the financial information presented in the consolidated financial statements prepared under IFRS, please refer to Section 6-"Alternative Performance Measures (APMs)" in the "Economic and Financial Report" chapter, and Note 9: "Alternative Performance Measures (APMs)" in the "Sustainability Report" chapter, both of which are included in the 2025 Annual Report, published on February 25, 2026 (http://www.santander.com/content/dam/santander-com/en/documentos/informe-financiero-anual/2025/ifa-2025-consolidated-annual-financial-report-en.pdf) . The ordinary measures included in this document are non-IFRS measures.

Does Not Constitute an Offer of Securities

Neither this document nor the information contained herein constitutes an offer to sell or a solicitation of an offer to purchase securities.

Past Performance Is Not Indicative of Future Results

Statements regarding historical performance or growth rates are not intended to imply that future performance, stock price, or future results (including earnings per share) for a given period will necessarily match or exceed those of a previous period. Nothing in this document should be construed as a profit forecast.

Third-Party Information

In this document, Santander references and relies on certain information and statistical data obtained from publicly available sources and third parties, which it considers to be reliable. Neither Santander nor its directors, management, or employees have independently verified the accuracy or completeness of such information, nor do they guarantee its quality, adequacy, legality, accuracy, or completeness, nor do they assume any obligation to update such information after the date of this document. Santander shall not be held liable under any circumstances for the use of such information, for any decision or action taken by any party based on such information, or for any errors, inaccuracies, or omissions in such information. The publicly available sources and third parties referenced or cited in this document retain all rights with respect to such information, and the use of such information should not be construed as granting any license to any third party.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

		Banco Santander, S.A.
Date:	April 14, 2026	By:	/s/ Pedro de Mingo Kaminouchi
			Name:	Pedro de Mingo Kaminouchi
			Title:	Head of Corporate Compliance

FAQ

What MREL changes did Banco Santander (BCDRF) disclose in this 6-K?

Banco Santander reported new binding MREL requirements for its resolution group. Total MREL is now 31.17% of risk-weighted assets and 11.86% of leverage exposure, while Subordinated MREL is 11.56% and 6.11%, respectively, replacing a prior notification from 2025.

Is Banco Santander (BCDRF) currently meeting its new MREL requirements?

Yes. As of 31 December 2025, Banco Santander’s resolution group structure of own funds and eligible liabilities satisfies both the Total MREL and Subordinated MREL requirements, providing regulatory comfort that the bank already complies with the updated loss-absorbing capacity thresholds.

How does the combined buffer affect Banco Santander’s (BCDRF) MREL levels?

The MREL requirement in risk-weighted terms excludes the Combined Buffer Requirement of 4.42%. When this capital buffer is added, Total MREL in terms of total risk-weighted assets rises to 35.59%, defining the effective loss-absorbing and capital stack regulators expect the group to maintain.

Who set Banco Santander’s (BCDRF) updated MREL requirements?

The updated MREL requirements were determined by the Single Resolution Board and formally notified by Banco de España. They apply to the resolution group headed by Banco Santander and reflect the group’s multiple point of entry resolution strategy and specific intragroup exposure considerations.

What metrics are used to express Banco Santander’s (BCDRF) MREL ratios?

Banco Santander’s MREL is expressed as a percentage of total risk-weighted assets (Total Risk Exposure Amount, TREA) and of leverage ratio exposure (LRE). Regulators specify separate percentages for Total MREL and Subordinated MREL using both TREA-based and leverage-based calculations.

What prior factors influenced Banco Santander’s (BCDRF) MREL determination?

The Total MREL requirement reflects a 20% downward adjustment of the market confidence charge and an adjusted regime for holdings of eligible liabilities in Banco Santander México. The new notification also incorporates completion of a 49% sale of Santander Bank Polska to Erste Group Bank.