UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 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 December, 2025.

Commission File Number 001-38755

Suzano S.A.
(Exact name of registrant as specified in its charter)

SUZANO INC.
(Translation of Registrant’s Name into English)

Av. Professor Magalhaes Neto, 1,752
10th Floor, Rooms 1010 and 1011
Salvador, Brazil 41 810-012
(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 ☑ 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): ☐

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): ☐

Enclosures:

Exhibit 99.1 – Shareholder's Agreement

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.

Date: December 19th, 2025


						SUZANO S.A.

			By:			/s/ Marcos Moreno Chagas Assumpção
			Name:			Marcos Moreno Chagas Assumpção
			Title:			Vice-President of Finance and Investor Relations

Suzano S.A. 6-K