6-K

UNITED STATESSECURITIES 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 November, 2025

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 2235Bloco A – Vila OlimpiaSão Paulo, SP 04543-011Federative 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

[Free English Translation]

BANCO SANTANDER (BRASIL) S.A.

Public-held Company with Authorized Capital

Corporate Taxpayer´s Registry No. 90.400.888/0001-42

Company Registry No. 35.300.332.067

NOTICE TO THE MARKET

BANCO SANTANDER (BRASIL) S.A. (“Santander Brasil” or “Company”), in compliance with the provisions of article 26, §3, item II of CVM Resolution No. 81, of March 29, 2022, as amended (“CVM Resolution 81/22”), to adapt to the regulations, hereby informs its shareholders and the market in general that it has resubmitted, on this date, the Remote Voting Ballot for the Extraordinary General Meeting of the Company, to be held on November 28, 2025, at 3:30 p.m., to include a field for shareholders to express their views on the establishment of the Fiscal Council, without any changes to the matters on the agenda.

The Company clarifies that votes already submitted will remain valid, in accordance with article 26, §5 of CVM Resolution 81/22, and that the deadline for shareholders to submit new voting instructions, if they wish, is November 25, 2025 (inclusive). To avoid conflicting voting instructions, the Company recommends that shareholders submit any new remote voting ballot to the same service provider previously used.

São Paulo, November 03, 2025.

Gustavo Alejo Viviani

Investor Relations Officer

BANCO SANTANDER (BRASIL) S.A.

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: November 3, 2025