Banco Santander (NYSE: SAN) buys back $701.6M in AT1 capital notes

Rhea-AI Filing Summary

Banco Santander, S.A. has completed a cash tender offer for one series of its U.S. dollar‑denominated Additional Tier 1 (AT1) securities. Holders tendered and the bank accepted $701.6 million aggregate principal amount of its 4.750% Non‑Step‑Up Non‑Cumulative Contingent Convertible Perpetual Preferred Tier 1 Securities, out of a $850 million maximum offer amount.

The accepted securities will be cancelled and will not be re‑issued or re‑sold, reducing this AT1 line to $298.4 million outstanding after the offer. The offer expired on June 9, 2026, and settlement is expected on June 11, 2026. All valid tenders were accepted without proration.

Insights

Bank capital structure analyst

Santander retires $701.6M of AT1 paper, trimming hybrid capital.

Banco Santander conducted a cash tender for up to $850,000,000 of its 4.750% Additional Tier 1 securities and accepted $701,600,000 that were validly tendered by the June 9, 2026 deadline. All accepted notes will be cancelled.

This reduces the outstanding amount of this AT1 issue to $298,400,000, modestly simplifying the bank’s hybrid capital stack. The purchase price of $1,001 per $1,000 nominal (100.1% of par) indicates a small premium to face value.

While the filing does not quantify impacts on regulatory capital ratios or interest expense, it documents an executed liability management transaction. Subsequent financial reports for periods after the expected settlement date of June 11, 2026 will reflect the lower outstanding principal on this AT1 line.

Key Figures

Maximum Offer Amount: $850,000,000 Principal Tendered and Accepted: $701,600,000 Outstanding After Offer: $298,400,000 +5 more

8 metrics

Maximum Offer Amount $850,000,000 Cash tender offer capacity for AT1 securities

Principal Tendered and Accepted $701,600,000 AT1 securities validly tendered by June 9, 2026

Outstanding After Offer $298,400,000 Remaining principal of 4.750% AT1 securities post-tender

Coupon Rate 4.750% Non-Step-Up Non-Cumulative Contingent Convertible Perpetual Preferred Tier 1 Securities

Purchase Price 100.1% of nominal Tender price for AT1 securities

Tender Consideration $1,001 per $1,000 Cash paid per $1,000 nominal amount tendered

Expiration Deadline June 9, 2026 Cut-off time 5:00 p.m. New York City time

Expected Settlement Date June 11, 2026 Date when cash payment and cancellation occur

Key Terms

Additional Tier 1 Securities, Contingent Convertible, Tender Offer, Offer to Purchase, +1 more

5 terms

Additional Tier 1 Securities financial

"its U.S. Dollar-Denominated Additional Tier 1 Securities"

Contingent Convertible financial

"Non-Step-Up Non-Cumulative Contingent Convertible Perpetual Preferred Tier 1 Securities"

Tender Offer financial

"announcing the results of its tender offer (the “Offer”) to purchase for cash"

A tender offer is a proposal made by a person or company to buy shares from existing shareholders at a set price, usually higher than the current market value, within a specific time frame. It matters to investors because it can lead to a change in ownership or control of a company, and shareholders must decide whether to sell their shares at the offered price.

Offer to Purchase regulatory

"The Offer was made on the terms and subject to the conditions set out in the Offer to Purchase"

An offer to purchase is a formal proposal from one party to buy a specific amount of shares or assets from another party at a set price. It matters to investors because it signals interest in acquiring ownership and can influence the value or control of a company. Think of it as someone putting forward a clear, serious offer to buy something they find valuable.

Schedule TO regulatory

"a tender offer statement on Schedule TO, accompanied by the Offer to Purchase"

A phrase indicating that a company plans or intends to hold an event, publish information, or take an action at a specified future time, but that the timing is not guaranteed and may change. For investors it signals an expected milestone—like an earnings call, product launch, or filing—so think of it as a calendar note rather than a firm promise; timing shifts can affect trading, expectations, and planning.

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

Available on EDGAR 06/10/2026 - 06:08 AM Accepted by SEC EDGAR 06/10/2026 - 06:07 AM Learn about SEC filing dates

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 June, 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 June 10, 2026

Item 1

Banco Santander, S.A., in accordance with the provisions of the securities market legislation, communicates the following:

OTHER RELEVANT INFORMATION

BANCO SANTANDER, S.A. ANNOUNCES RESULTS OF TENDER OFFER FOR ONE SERIES OF ITS U.S. DOLLAR-DENOMINATED ADDITIONAL TIER 1 SECURITIES

Further to the communication of inside information made on May 27, 2026 (registered under number 3240), Banco Santander, S.A. (the “Offeror” or “Banco Santander”) is today announcing the results of its tender offer (the “Offer”) to purchase for cash up to $850,000,000 (the “Maximum Offer Amount”) of its outstanding 4.750% Non-Step-Up Non-Cumulative Contingent Convertible Perpetual Preferred Tier 1 Securities of Banco Santander (the “Securities”).

The Offer was made on the terms and subject to the conditions set out in the Offer to Purchase dated May 27, 2026 (the “Offer to Purchase”). Capitalized terms not otherwise defined in this announcement have the same meaning as in the Offer to Purchase.

Based on information provided by the Tender Agent, $701,600,000 aggregate principal amount of the Securities listed in the table below were validly tendered and not validly withdrawn by 5:00 p.m., New York City time, on June 9, 2026 (the “Expiration Deadline”), as more fully set forth below. Banco Santander has accepted all Securities that were validly tendered and not validly withdrawn prior to the Expiration Deadline, without proration. The Settlement Date is expected to be June 11, 2026.

Securities purchased by Banco Santander pursuant to the Offer will be cancelled and will not be re-issued or re-sold. Securities which have not been validly submitted and accepted for purchase pursuant to the Offer will remain outstanding. The aggregate principal amount of Securities outstanding after the Offer is $298,400,000.

The table below sets forth, among other things, the principal amount of the Securities validly tendered and accepted pursuant to the Offer:

Securities	CUSIP / ISIN	Purchase Price(1)	Tender Consideration(2)	Aggregate Principal Amount Accepted	Aggregate Principal Amount Outstanding After the Offer
4.750% Non-Step-Up Non-Cumulative Contingent Convertible Perpetual Preferred Tier 1 Securities	CUSIP No. 05971K AH2 / ISIN: US05971KAH23	100.1%	$1,001 per $1,000 of nominal amount tendered, provided that Securities may only be tendered in multiples of $200,000	$701,600,000	$298,400,000

(1) The Purchase Price shall be 100.1% of the nominal amount of the Securities accepted for purchase pursuant to the Offer. Securities could only be tendered in multiples of $200,000, being the liquidation preference of the Securities.

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(2) The Tender Consideration payable on the Settlement Date to a holder whose Securities are validly tendered and accepted for purchase by the Offeror pursuant to the Offer will be an amount per $1,000 of nominal amount of such tendered securities in U.S. dollars equal to the product of (x) the Purchase Price and (y) the nominal amount of such Securities. In addition to the Tender Consideration, holders whose Securities are validly tendered and accepted for purchase will receive the Distribution Payment, if any,  in respect of such Securities. With respect to any Securities validly tendered and accepted for purchase by the Offeror pursuant to the Offer, the “Distribution Payment” is an amount in cash (rounded to the nearest $0.01, with $0.005 being rounded upwards) equal to the Distribution on such Securities. “Distributions” consist of distributions accrued and unpaid (if any) on the Securities from (and including) the distribution payment date in respect of such Securities immediately preceding the Settlement Date to (but excluding) the Settlement Date, calculated in accordance with the terms and conditions of the Securities, unless distributions on the Securities for that period are cancelled.

D.F. King & Co., Inc. acted as tender agent for the Offer. Santander US Capital Markets LLC acted as Dealer Manager for the Offer. Questions regarding the Offer should be directed to:

Tender Agent
D.F. King & Co., Inc.	Email: san@dfking.com
28 Liberty Street, 53rd Floor New York, New York 10005 United States	Banks and Brokers call: (646) 963-9141 All others call toll free: (866) 340-7108 Website: www.dfking.com/santander
Dealer Manager
Santander US Capital Markets LLC	437 Madison Avenue New York, New York 10022 United States Tel (U.S. Toll Free): +1 (855) 404-3636 Tel (collect): +1 (212) 350-0660 Attn: Liability Management Team Email (Americas): AmericasLM@santander.us Email (Europe): LiabilityManagement@gruposantander.com

Boadilla del Monte (Madrid), June 10, 2026

Disclaimer

This announcement and the Offer to Purchase (including the documents incorporated by reference therein) contain important information which should be read carefully. If you are in any doubt as to the contents of this announcement or the Offer to Purchase or the action you should take, you are recommended to seek your own financial, legal, regulatory and tax advice, including as to any tax consequences, immediately from your stockbroker, bank manager, attorney, accountant or other independent financial, tax or legal adviser.

Additional Information in Respect of the Offer and Where to Find It

Banco Santander has filed with the Securities and Exchange Commission (the “SEC”) a tender offer statement on Schedule TO, accompanied by the Offer to Purchase and related documents relating to the Offer. Holders are advised to read carefully the tender offer statement, the Offer to Purchase and other documents which Banco Santander will file with the SEC as they contain important information about the Offer. Copies of these documents are available for free by visiting EDGAR on the SEC website at www.sec.gov. In addition, copies of the Schedule TO and the documents filed with it may be obtained free of charge by contacting Investor Relations, Ciudad Grupo Santander, Avenida de Cantabria s/n, 28660 Boadilla del Monte, Madrid, Spain (telephone: (011) 34-91-259-6520).

Forward-Looking Statements

This announcement contains certain forward-looking statements within the meaning of Section 21E of the US Securities Exchange Act of 1934, as amended, and section 27A of the US Securities Act of 1933, as amended, with

2 

respect to Banco Santander, S.A. together with its subsidiaries (the “Group”) and its current goals and expectations. Statements that are not historical or current facts, including statements about the Group’s or its directors’ and/or management’s beliefs and expectations, are forward looking statements. Words such as, without limitation, ‘believes’, ‘achieves’, ‘anticipates’, ‘estimates’, ‘expects’, ‘targets’, ‘should’, ‘intends’, ‘aims’, ‘projects’, ‘plans’, ‘potential’, ‘will’, ‘would’, ‘could’, ‘considered’, ‘likely’, ‘may’, ‘seek’, ‘estimate’, ‘probability’, ‘goal’, ‘objective’, ‘deliver’, ‘endeavour’, ‘prospects’, ‘optimistic’ and similar expressions or variations on these expressions are intended to identify forward looking statements. These statements concern or may affect future matters, including but not limited to matters, influences and factors which are beyond the Group’s control. Please refer to the latest Annual Report on Form 20-F filed by Banco Santander, S.A. with the US Securities and Exchange Commission (the SEC), which is available on the SEC’s website at www.sec.gov, for a discussion of certain factors and risks. Banco Santander, S.A. may also make or disclose written and/or oral forward-looking statements in other written materials and in oral statements made by the directors, officers or employees of Banco Santander, S.A. to third parties, including financial analysts.

Except as required by any applicable law or regulation, the forward-looking statements contained in this document are made as of today’s date, and the Group expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward looking statements contained in this document whether as a result of new information, future events or otherwise. The information, statements and opinions contained in this document do not constitute a public offer under any applicable law or an offer to sell any securities or financial instruments or any advice or recommendation with respect to such securities or financial instruments.

3 

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:	June 10, 2026		By:	/s/ Pedro de Mingo Kaminouchi
				Name:	Pedro de Mingo Kaminouchi
				Title:	Head of Corporate Compliance

FAQ

What did Banco Santander (SAN) announce in this Form 6-K?

Banco Santander announced the results of a cash tender offer for one series of its U.S. dollar-denominated Additional Tier 1 securities. The bank accepted and will cancel $701.6 million of 4.750% perpetual preferred Tier 1 securities, reducing the outstanding amount of this issue.

How much of Banco Santander’s AT1 securities were tendered and accepted?

Investors tendered and Banco Santander accepted $701.6 million aggregate principal of its 4.750% Non-Step-Up Non-Cumulative Contingent Convertible Perpetual Preferred Tier 1 Securities. All validly tendered securities before the June 9, 2026 expiration deadline were accepted without proration under the offer terms.

What was the maximum amount Banco Santander offered to purchase in the tender?

Banco Santander’s tender offer targeted up to $850 million aggregate principal amount of its outstanding 4.750% Additional Tier 1 securities. Actual participation reached $701.6 million, which the bank accepted in full, leaving a smaller remaining principal amount outstanding after completion of the offer.

What happens to the AT1 securities purchased by Banco Santander?

The securities purchased in the tender offer will be cancelled and will not be re-issued or re-sold. This permanently reduces the principal of this 4.750% Additional Tier 1 line, while any securities not tendered or accepted remain outstanding on the same terms as before the transaction.

How much of this AT1 issue remains outstanding after the tender offer?

After accepting $701.6 million of securities in the tender offer, Banco Santander states that $298.4 million aggregate principal of the 4.750% Non-Step-Up Non-Cumulative Contingent Convertible Perpetual Preferred Tier 1 Securities remains outstanding. These remaining securities continue under their existing coupon and structural terms.

When did Banco Santander’s AT1 tender offer expire and settle?

The tender offer expired at 5:00 p.m. New York City time on June 9, 2026. Banco Santander expects the settlement date to be June 11, 2026, when cash consideration will be paid and the accepted Additional Tier 1 securities will be cancelled and removed from the outstanding amount.