6-K

UNITEDSTATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549

FORM6-K

REPORTOF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

Forthe month of May 2026

Commission File Number: 001-40786

SigmaLithium Corporation

(Translation of registrant's name into English)

181,Bay Street, Suite 4400Toronto, Ontario, M5J 2T3, Canada

(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 [X]

EXHIBITINDEX

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.

SIGMALITHIUM TO RELEASE FIRST QUARTER 2026EARNINGS RESULTS ON MAY 15, 2026

São Paulo, May 05,2026 – Sigma Lithium Corporation (TSXV/NASDAQ: SGML, BVMF: S2GM34), (“Sigma Lithium” or “the Company”), a leading global lithium producer dedicated to powering the next generation of electric batteries with socially and environmentally sustainable lithium concentrate, announces today that it will release its first quarter 2026 earnings results before the market opens on Friday, May 15, 2026.

The Company will hold a conference call to discuss its first quarter 2026 earnings results shortly after, on  Friday, May 15, 2026, at 8:30 a.m. EST. Access to the call will be available via webcast. A link to the webcast can be found on Sigma Lithium’s website at:

https://ir.sigmalithiumcorp.com/events/

Webcast Details:

• Event Title: Sigma Lithium First Quarter 2026 Earnings Results Call
• Event Date: May 15, 2026
• Start Time: 8:30 a.m. EST

Attendee URL:

https://mzgroup.zoom.us/webinar/register/WN_US0MoDbgTVyJLtNCQeZrIQ#/registration

ABOUT SIGMA LITHIUM

Sigma Lithium Corporation (NASDAQ: SGML, TSXV: SGML, BVMF: S2GM34), (“Sigma Lithium” or “the Company”) is the largest producer of lithium oxide concentrate in the Americas¹ 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% of water, zero use of toxic chemicals, zero tailings and the use of 100% 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 38,000–40,000 tonnes of LCE) 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. For more information about Sigma Lithium, visit our website

FOR ADDITIONAL INFORMATION PLEASECONTACT

Anna Hartley, Vice President of Global Banking and Investor Relations

[email protected]

+44 7866 458 093

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Mariana Bengtson, Investor Relations Manager

[email protected]

+55 11 9 2144 2750

SigmaLithium

FORWARD-LOOKINGSTATEMENTS

Thisnews release includes certain “forward-looking information” under applicable Canadian and U.S. securities legislation, includingbut not limited to statements relating to timing and costs related to the general business and operational outlook of the Company, theenvironmental footprint of tailings and positive ecosystem impact relating thereto, donation and upcycling of tailings, timing and quantitiesrelating to tailings and Green Lithium, achievements and projections relating to the Zero Tailings strategy, achievement of ramp-up volumes,production estimates and the operational status of the Grota do Cirilo Project, and other forward-looking information. All statementsthat address future plans, activities, events, estimates, expectations, or developments that the Company believes, expects, or anticipateswill or may occur is forward-looking information, including statements regarding the potential development of mineral resources and mineralreserves which may or may not occur. Forward-looking information contained herein is based on certain assumptions regarding, among otherthings: general economic and political conditions; the stable and supportive legislative, regulatory and community environment in Brazil;demand for lithium, including that such demand is supported by growth in the electric vehicle market; the Company’s market positionand future financial and operating performance; the Company’s estimates of mineral resources and mineral reserves, including whethermineral resources will ever be developed into mineral reserves; and the Company’s ability to operate its mineral projects includingthat the Company will not experience any materials or equipment shortages, any labor or service provider outages or delays or any technicalissues. Although management believes that the assumptions and expectations reflected in the forward-looking information are reasonable,there can be no assurance that these assumptions and expectations will prove to be correct. Forward-looking information inherently involvesand is subject to risks and uncertainties, including but not limited to that the market prices for lithium may not remain at current levels;and the market for electric vehicles and other large format batteries currently has limited market share and no assurances can be givenfor the rate at which this market will develop, if at all, which could affect the success of the Company and its ability to develop lithiumoperations. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differmaterially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking information.The Company disclaims any intention or obligation to update or revise any forward-looking information, whether because of new information,future events or otherwise, except as required by law. For more information on the risks, uncertainties and assumptions that could causeour actual results to differ from current expectations, please refer to the current annual information form of the Company and other publicfilings available under the Company’s profile atwww.sedarplus.com.

Neither the TSX Venture Exchange nor its Regulation ServicesProvider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy ofthis news release.

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