SUZ 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 August, 2026.

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 – Deal Imetame Logística

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: August 31st, 2026

Document

NOTICE TO THE MARKET

SUZANO S.A.

Publicly-Held Company

Corporate Taxpayer ID (CNPJ/MF): 16.404.287/0001-55

Company Registry (NIRE): 29.3.0001633-1

São Paulo, August 31, 2026 – Suzano S.A. ("Suzano" or "Company") (B3: SUZB3 | NYSE: SUZ), in line with best corporate governance practices, hereby informs its shareholders and the market that it has entered into an agreement with Imetame Group to acquire a 10% equity stake in Imetame Logística Porto S.A. ("Imetame Logística" and the "Transaction"), the company responsible for developing a greenfield port project currently under construction in the municipality of Aracruz, Espírito Santo, Brazil. The project comprises the development of five specialized terminals (containers, general cargo, dry bulk, liquid bulk, and ship-to-ship operations).

Suzano's 10% equity stake in Imetame Logística will be acquired through the contribution of land owned by Suzano, strategically located for the development of the project, without affecting the operational or economic performance of the Company’s Aracruz Unit, which is located in the same region.

The port hub is expected to start general cargo operations in early 2027, with a limited scope corresponding to the activities planned for its first phase. The container terminal, a joint venture in which Hanseatic Global Terminals (HGT), the terminal division of Hapag-Lloyd, currently the world's fifth-largest container shipping company, holds a 50% stake, is expected to start operations in mid-2028. The terminal is expected to have an estimated capacity of approximately 1.2 million TEUs per year, 750 meters of quay length, and state-of-the-art container handling equipment. With a 17-meter operational depth, the terminal will be capable of accommodating large vessels, a feature that enhances its logistics competitiveness. The remaining terminals will be developed in subsequent phases, in accordance with the project's development schedule.

Additionally, Suzano estimates that the Transaction will not represent a material investment for the Company in terms of its capital structure or investment plan for the coming years. Furthermore, no capital expenditures (capex) are planned for 2026 in connection with its equity stake in Imetame Logística.

Suzano believes that the Transaction is aligned with its long-term value creation strategy, combining its business expertise in port logistics with the potential to monetize its land assets. In partnership with groups recognized for their capabilities in developing and operating infrastructure projects, the Company believes that the project has the attributes to establish itself as an important logistics platform for Brazilian foreign trade.

Closing of the Transaction is subject to customary conditions precedent for transactions of this nature, including approval by the regulatory authority.

Finally, by disclosing the information contained in this Notice to the Market, the Company reiterates its commitment to transparency toward its shareholders, investors, and the market in general.

São Paulo, August 31, 2026.

Marcos Moreno Chagas Assumpção

Executive Vice President, Finance, Investor Relations and DigitalTech