Ms. Anna Hartley reports

SIGMA LITHIUM ANNOUNCES FULL RESUMPTION OF MINING-INDUSTRIAL OPERATIONS; SIGNED A TAC AGREEMENT WITH THE STATE OF MINAS GERAIS; EXPECTS TO PRODUCE 240,000T WITHIN 12 MONTHS

Sigma Lithium Corp. has signed a terms for adjustment of procedures agreement (Termo de Ajuste de Conduta) with the State of Minas Gerais.

Mining and industrial operations fully back on-line

Following the signing of the TAC agreement, Sigma Lithium's mining and industrial operations are fully back on-line, with the company resuming its regular operating activities.

The company remains focused on ramping up mining operations and advancing its expansion plans, as per its second quarter 2026 announcement:

• 240,000 tonnes of lithium oxide concentrate within 12 months;

• 330,000 tonnes production in fiscal year 2027.

Operations related to the sale of high-purity lithium fines consisting of reprocessed tailings, as well as other intermediate grade products, continued without disruption throughout the partial suspension of operations.

The signing of the TAC agreement reflects Sigma Lithium's continued engagement with Minas Gerais State authorities and the company's unwavering commitment to operating under the highest environmental and regulatory global framework in the Vale do Jequitinhonha, producing the quintuple zero lithium. During negotiations, Minas Gerais environmental authorities reviewed an extensive amount of factual and quantitative environmental technical documentation provided by the company.

Sigma Lithium estimates that the execution of the adjustments of environmental procedures under the TAC agreement will require capex of approximately $1-million (U.S.). The company agreed to the payment of up to $540,000 (U.S.) for certain fines, related to environmental matters dating from 2013 to 2022.

Sigma Lithium vehemently denies any wrongdoing with respect to the key claims raised in connection with the company's operations and reaffirms that the company:

• Has not misrepresented information filed with environmental authorities since 2018;

• Has not commercially sold lithium materials prior to May, 2023;

• Denies claims alleging that two houses located outside Sigma Lithium's licensed area have been negatively impacted by its activities. Nevertheless, the company agreed to widen and gravel their access roads, as part of the TAC agreement.

TAC agreement background

A TAC agreement is a standardized form of agreement between regulators and corporates in Brazil. It translates into "terms for adjustment of procedures." The adjustments of procedures must be mutually agreed between the regulatory body (federal or state) and the company. A significant majority of publicly traded companies in Brazil have TAC agreements with various regulators (both federal and state), which are used to resolve corporate and environmental matters, as a TAC agreement provides legal certainty for the company by clearly outlining actions to be undertaken and deadlines for their execution.

Qualified person

The qualified person for the technical information contained herein is Alexandre Rodrigues Cabral, PEng, member of the Ordre des Ingenieurs du Quebec (OIQ membership No. 105796), who is considered, by virtue of his education, experience and professional association, a qualified person under the terms of NI 43-101. Mr. Cabral is not considered an independent QP under NI 43-101 as he is a Sigma Lithium director and chair of the company's technical committee. He has reviewed and approved the technical and scientific content of this release.

About Sigma Lithium Corp.

Sigma Lithium is the largest producer of lithium oxide concentrate in the Americas and dedicated to industrializing socially and environmentally sustainable lithium materials to supply global producers of batteries for energy security.

We seek Safe Harbor.