Ms. Anna Hartley reports

SIGMA LITHIUM CELEBRATED 1,010 DAYS WITHOUT ACCIDENTS AND ZERO FATALITIES; OPERATIONS ON TRACK TO REACH 240KTPY LITHIUM OXIDE; CATEGORICALLY RESPONDS TO INACCURATE MEDIA REPORTS

Sigma Lithium Corp. celebrated 1,010 days without accidents and continued having zero fatalities since it started activities 14 years ago.

Mining operations on track to achieve guidance

The company successfully concluded a full ramp-up of mining operations and is on track to achieve its production guidance 240,000 tonnes per year of lithium oxide concentrate. The large mining trucks of up to 60-tonne capacity and large excavators of 75-tonne capacity have been fully mobilized in four shifts, resulting in the creation of approximately 600 new jobs, driving total direct employment to over 1,000 jobs.

Sigma Lithium's cleantech industrial dense media separation technology has been globally recognized as an innovative sustainable solution in lithium processing and separation: without the use of drinking water or toxic chemicals, and 100 per cent powered by renewable energy.

The greentech industrial plant does not require a mud tailings dam and the plant's dry stacked tailings are reprocessed or sold as low-grade high-purity lithium oxide concentrate. These sales represent a "de facto green premium," demonstrating that investing in cleantech can generate incremental cash flow as a bonus. As a result of this technological advantage, the company expects to achieve full circularity next quarter, becoming one of the first zero mining waste battery materials industrial sites globally.

Sigma Lithium has been successfully utilizing modern technologies of bioengineering to germinate grass and regenerate the slope of existing waste rock piles, incorporating them to the hilly landscape of Vale do Jequitinhonha.

Inaccurate media reports

The company vehemently denies as "fake news" the inaccurate media reports published yesterday, May 11, 2026, that incorrectly: (i) denominated its waste piles as "banned" by the Ministry of Labor and Employment (MLE); (ii) stated that an inspector from the MLE inspected Sigma Lithium's operations.

Brazil's mining regulator, Agencia Nacional de Mineracao (ANM), publicly issued an official technical statement about Sigma Lithium's waste rock piles, directly attesting their safety, as mentioned in a news release issued by Sigma Lithium on Feb. 4, 2026.

The swift action by the mining regulator to conduct the inspections and issue a technical opinion regarding the company's waste rock piles underscores the official effort by the government of Brazil to protect the legal security and certainty for companies conducting mining activities in the country, underscoring the strong governance of the industry.

The government of Brazil, represented by its various ministries, including the MLE, has demonstrated its commitment to fostering the industrial processing of critical minerals oxides in Brazil, of which Sigma Lithium has been at the forefront since 2023. The company's importance is heightened by its key role in the development of the region where it operates in the state of Minas Gerais, Vale do Jequitinhonha, where Sigma Lithium is the largest investor and employer.

The company is responsible for the generation of approximately 20,000 employment positions in the Vale do Jequitinhonha region, as follows: total indirect jobs of over 12,000; total jobs created by microcredit at 2,000; and total jobs created by the small-scale agriculture irrigation program surpassed 7,000.

The ANM is the only regulatory authority with powers over mining activities in Brazil and equipped with the capabilities to execute technical mining audits. The mining regulator technical note was the definitive technical opinion over the safety of the company's waste piles.

As previously mentioned, there is a continuing administrative enquiry with respect to certain of the company's waste piles by the MLE, which does not have a material effect on Sigma Lithium's capacity to continue to execute its mining activities. As part of this continuing administrative enquiry, Sigma Lithium received a fine from the MLE on May 8 for $10,000 reais (approximately $2,000 (U.S.)), a relatively small amount.

The timely involvement of the mining regulator supports the company's clarification that its "waste piles" are, in fact, hard schist rock mined from the pits and are a common feature of most base metals operations with host mineral rocks and contact zones.

Unusual increase in volume of puts coincides with spread of false information

The inaccurate news reports published yesterday fit a pattern of the negative media campaigns conducted against Sigma Lithium disseminating false, inaccurate and misleading information, as reported by the company on Jan. 23d, 2026. Sigma Lithium is in close contact with the appropriate authorities, including FINRA (U.S. Securities and Exchange Commission), regarding these events.

The false media reports followed an unusual and substantial increase in the volumes of put options on the company's shares negotiated at $21.50 on May 8, expiring on May 15, 2026 (the date scheduled for the release of Q1 (first quarter) 2026 earnings). Yesterday, Sigma Lithium's share price experienced substantial volatility and ended the day down by 6.5 per cent, compared with a significant increase in the share price of other lithium producers.

About Sigma Lithium Corp.

Sigma Lithium is the largest producer of lithium oxide concentrate in the Americas (1) and dedicated to industrializing socially and environmentally sustainable lithium materials to supply global producers of batteries for energy security.

The company runs one of the world's largest lithium production sites -- the fifth-largest industrial-mineral complex for lithium oxide concentrate -- at its Grota do Cirilo operation in Brazil. Sigma Lithium is at the forefront of environmental and social sustainability in the electric battery materials supply chain. The company's greentech industrial plant combines the reuse of 100 per cent of water, zero use of toxic chemicals, zero tailings and the use of 100 per cent renewable electricity. For more than two years, Sigma Lithium has not experienced an accident with lost time.

Sigma Lithium currently has a nameplate capacity to produce 270,000 tonnes of lithium oxide concentrate on an annualized basis (approximately 38,000 to 40,000 tonnes of LCE (lithium carbonate equivalent)) at its mine and state-of-the-art greentech industrial plant. The company has initiated a phase 2 expansion designed to close to double production capacity to 520,000 tonnes.

(1) U.S. Geological Survey.