UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE

SECURITIES EXCHANGE ACT OF 1934

For the month of July, 2026

Commission File Number: 001-34476

BANCO SANTANDER (BRASIL) S.A.

(Exact name of registrant as specified in its charter)

Avenida Presidente Juscelino Kubitschek, 2041 and 2235
Bloco A – Vila Olimpia
São Paulo, SP 04543-011
Federative Republic of Brazil

(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 _______

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):

Yes _______ No ___X____

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):

Yes _______ No ___X____

Indicate by check mark whether by furnishing the information contained in this Form, the Registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934:

Yes _______ No ___X____

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): N/A

BANCO SANTANDER (BRASIL) S.A.

Publicly-Held Company with Authorized Capital

CNPJ/MF 90.400.888/0001-42 - NIRE 35.300.332.067

CALL NOTICE - EXTRAORDINARY GENERAL MEETING - Shareholders are hereby invited to attend the Extraordinary General Meeting ("EGM") to be held on August 18, 2026, at 3:00 P.M., at the Company's headquarters, located at Avenida Presidente Juscelino Kubitschek nº 2041 – mezzanine, Vila Nova Conceição, São Paulo/SP, to resolve on the following Agenda:

(a) TO FIX the number of members that will compose the Board of Directors of the Company;

(b) ELECT two (2) new members to compose the Company's Board of Directors; and

(c) As a result of the resolution in the previous item, CONFIRM the composition of the Company's Board of Directors.

Observations for participation and Voting during the Meeting

Participation in the Meeting: Shareholders, their legal representatives or attorneys-in-fact may participate in the Meeting in any of the following ways:

In person - The shareholders or their legal representatives shall present themselves for the EGM with the appropriate identity documents. In the event of representation of a shareholder by an attorney-in-fact, shareholders shall provide the Company with a power of attorney granted according to the applicable law, to be delivered at the Company's Headquarters, at least seventy-two (72) hours before the EGM is held;

Remote Voting Ballot: the Company implemented the remote voting system pursuant to CVM Resolution 81/22, as amended, enabling our Shareholders to send remote voting ballots directly to the Company, to the bookkeeper, to the respective custodian agents or to the Central Depository, in accordance with the procedures described in the General Meeting Participation Manual.

As provided for in Article 5, § 4, of CVM Resolution No. 81/22, with the amendments introduced by CVM Resolutions No. 59/21 and 204/24, the Company understands that holding the EGM in person allows for a closer environment between shareholders and the attending Company's management, facilitating the clarification of doubts and the discussion of relevant matters, enabling a closer environment to deliberations and decision-making. In addition, it ensures greater security in the transmission of information, avoiding risks associated with technical or cyber failures.

In this sense, the Company recommends and encourages the participation of its shareholders in its Meeting, using the various participation channels made available, whether through the use of remote voting instruments, through the available electronic means or even by sending written votes to the Company or granting standardized proxies with voting instructions, in accordance with the instructions made available in the Management Proposal for the Extraordinary General Meeting of August 18, 2026.

General Instructions

1. As provided in CVM Resolution No. 70/22, the minimum percentage of participation in the voting capital required for the application of the cumulative voting process (processo de voto múltiplo) for the election of the members of the Board of Directors is of 5%;

2. As provided in § 2 of article 161 of Law No. 6,404/76 and art. 4 of CVM Resolution No. 70/22, the installation of a Fiscal Council by the General Meeting shall occur at the request of shareholders representing at least 2% (two percent) of the common shares, or 1% (one per cent) of preferred shares; and

3. The documents related to the matters to be examined and resolved at the EGM are available to shareholders (i) at the Company's headquarters, at Avenida Presidente Juscelino Kubitschek, nº 2041, Wtorre JK, 9th floor - Corporate Legal Department, where they can be consulted on business days, from 10:00 a.m. until 4:00 p.m., and on its investor relations website (www.ri.santander.com.br – at Corporate Governance >> Minutes of the Meeting); (ii) on the website of the CVM – Comissão de Valores Mobiliários (www.cvm.gov.br) and (iii) on the website of the stock exchange B3 S.A. - Brasil, Bolsa, Balcão (http://www.b3.com.br).

São Paulo, July 16, 2026

Deborah Stern Vieitas

Chairwoman of the Board of Directors.

___________________________________________________

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, thereto duly authorized.

Date: July 16, 2026

Banco Santander (Brasil) S.A.

By:	/S/ Reginaldo Antonio Ribeiro
	Reginaldo Antonio Ribeiro Officer without specific designation



By:	/S/ Carlos Ignacio Muñiz Gonzalez Blanch
	Carlos Ignacio Muñiz Gonzalez Blanch Vice - President Executive Officer

Banco Santander (Brasil) S.A. 6-K