SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16
OR 15D-16 OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of June, 2026

(Commission File No. 1-14862 )

BRASKEM S.A.

(Exact Name as Specified in its Charter)

N/A

(Translation of registrant's name into English)

Rua Eteno, 1561, Polo Petroquimico de Camacari
Camacari, Bahia - CEP 42810-000 Brazil

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover 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). _____

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). _____

Indicate by check mark whether the registrant by furnishing the information contained in this Form 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): 82- _____.

BRASKEM S.A.

Corporate Taxpayer ID (C.N.P.J.) No. 42.150.391/0001-70

State Registration (NIRE) 29300006939

Publicly-held company

MATERIAL FACT

Braskem S.A. (“Braskem” or “Company”) (Ticker B3: BRKM3, BRKM5 and BRKM6; NYSE: BAK; LATIBEX: XBRK), further to the Material Fact of September 26, 2025 and June 25, 2026, hereby informs its shareholders and the market in general that it has provided certain holders and investment managers of one or more of senior securities and debenture holders issued or guaranteed by Braskem (“Investors”) with certain non-public information relating to Braskem and its subsidiaries (“Shared Information”), in the context of a possible reorganization of its capital structure (“Restructuring”).

Under the terms of the confidentiality agreements entered into on June 11, 2026, between Braskem and the Investors (collectively, the “Confidentiality Agreements”), Braskem agreed to publicly disclose all material information provided to the Investors after the termination of the period established in the Confidentiality Agreements. The Shared Information is publicly available on the Braskem website at the link, and is provided to fulfill Braskem’s obligations under the Confidentiality Agreements and in compliance with applicable legal rules.

Since the execution of the Confidentiality Agreements, Braskem and the Investors, through their respective advisors, have prepared and exchanged the following information:

During this period, representatives and advisors from Braskem and the Investors participated in discussions and correspondence regarding the Proposals, including an in-person meeting held on June 11, 2026 among representatives and advisors from Braskem and the Investors, with no agreement reached between the parties regarding Braskem Proposal.

Given the short-term needs of the Company and the Company’s interest in negotiating a Restructuring under a stable environment, during that in-person meeting the Company requested the Investors to prioritize discussions on the process and framework rules to negotiate the terms of the Restructuring under the stable and protected environment provided by an extrajudicial reorganization proceeding in Brazil and, accordingly, requested to the Investors to provide a response with respect to the Company’s proposed process and framework rules on an expedited basis, by the beginning of the week following the June 11 meeting. The Investor Proposal with such response was received by the Company six business days after the meeting and in terms unacceptable to the Company. Therefore, Braskem indicated that it would not agree to the Investor Proposal.

The Company reassured the Investors that it is fully committed to continue discussions with its financial creditors in finding a consensual, structured, and orderly solution for its capital structure that ensures the continuance of its operations in the ordinary course of business.

The information contained in the Braskem Proposal is accurate as of the delivery date, has not been updated since the delivery date, and should not be used for any other purpose.

A copy of the terms of the Proposals are available on the Braskem website at the link. No agreement regarding any of the Proposals or any other transaction has been reached to date.

The Braskem Proposal contain projections regarding prices, supply, sales volume, consumption and feedstock supply, costs, production and utilization rate, as well as Braskem's financial indicators, up to 2035. The projections presented are hypothetical data and forecasts that reflect the current expectations of Braskem's management and should not be interpreted as guarantees or promises of performance, being subject to risks and uncertainties associated with the economic, regulatory, and competitive conditions of the markets in which Braskem operates, and may therefore differ materially from the figures and results actually recorded by Braskem. The Company clarifies that the projections contained in the materials and the Braskem Proposal should not be considered as guidance and were prepared in the context of negotiations with Investors.

The Company clarifies that the projections contained in Braskem's Shared Information should not be considered as guidance and were prepared in the context of the Restructuring.

Braskem will keep the market informed of any material developments on this matter, in compliance with applicable laws.

Additional information may be obtained from the Investor Relations Department by telephone at +55 (11) 3576-9531 or by e-mail at braskem-ri@braskem.com.br.

São Paulo, June 25, 2026

Carlos Augusto Machado Pereira de Almeida Brandão

Chief Financial and Investor Relations Officer

Braskem S.A.

SIGNATURES

        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, 2026

FORWARD-LOOKING STATEMENTS

This Material Fact may contain forward-looking statements. These statements are not historical facts, but rather are based on the current view and estimates of the Company's management regarding future economic and other circumstances, industry conditions, financial performance and results, including any potential or projected impact regarding the geological event in Alagoas and related legal procedures on the Company's business, financial condition and operating results. The words "project," "believe," "estimate," "expect," "plan", "objective" and other similar expressions, when referring to the Company, are used to identify forward-looking statements. Statements related to the possible outcome of legal and administrative proceedings, implementation of operational and financing strategies and investment plans, guidance on future operations, the objective of expanding its efforts to achieve the sustainable macro objectives disclosed by the Company, as well as factors or trends that affect the financial condition, liquidity or operating results of the Company are examples of forward-looking statements. Such statements reflect the current views of the Company's management and are subject to various risks and uncertainties, many of which are beyond the Company's control. There is no guarantee that the events, trends or expected results will actually occur. The statements are based on various assumptions and factors, including, but not limited to, general economic and market conditions, industry conditions and operating factors, availability, development and financial access to new technologies. Any change in these assumptions or factors, including the projected impact from the joint venture and its development of technologies, from the geological event in Alagoas and related legal procedures and the unprecedented impact on businesses, employees, service providers, shareholders, investors and other stakeholders of the Company could cause effective results to differ significantly from current expectations. For a comprehensive description of the risks and other factors that could impact any forward-looking statements in this document, especially the factors discussed in the sections, see the reports filed with the Brazilian Securities and Exchange Commission (CVM). This Material Fact does not constitute any offer of securities for sale in Brazil. No securities may be offered or sold in Brazil without being registered or exempted from registration, and any public offer of securities carried out in Brazil must be made through a prospectus, which would be made available by Braskem and contain detailed information on Braskem and its management, as well as its financial statements.