6-K

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 June, 2024.

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 – Cerrado Project Start-up Update

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: June 25, 2024

Document

SUZANO S.A.

Publicly Held Company

Corporate Taxpayer ID (CNPJ/MF) No. 16.404.287/0001-55

Company Registry (NIRE) 29.3.0001633-1

MATERIAL FACT

São Paulo, June 25th, 2024 – Suzano S.A. (“Company” or “Suzano”) (B3:SUZB3 / NYSE:SUZ), in compliance with the provisions set forth in paragraph 4, article 157 of Law 6,404, of December 15th, 1976, as amended (“Brazilian Corporation Law”), with CVM Resolution 44, of August 23rd, 2021, as amended, and in reference to the Material Fact published on August 2nd, 2023, hereby informs its shareholders and the market in general that the operational start-up of the new pulp mill in Ribas do Rio Pardo, located in the state of Mato Grosso do Sul (“Cerrado Project”), will take place in July 2024.

The Cerrado Project is in its final commissioning phase and the Company’s planning aims to ensure the appropriate execution of the start-up of the new plant and the expected performance of its learning curve.

The other information and estimates disclosed about the Cerrado Project remain valid and unchanged.

Through the information disclosed in this Material Fact, the Company reiterates its commitment to transparency with shareholders, investors and the market in general.

São Paulo, June 25th, 2024.

Marcelo Feriozzi Bacci

Chief Financial and Investor Relations Officer