Sigma Lithium — Proxy Solicitation & Information Statement 2025

Jun 2, 2025

SIGMA LITHIUM

Sigma Lithium Corporation
181 Bay Street, Suite 4400
Toronto, Ontario, M5J 2T3

NOTICE OF ANNUAL MEETING OF SHAREHOLDERS

NOTICE IS HEREBY GIVEN THAT the annual meeting (the "Meeting") of the shareholders ("Shareholders") of Sigma Lithium Corporation (the "Corporation") will be held on Monday, June 30, 2025 at 11:00 a.m. (Toronto time), by virtual only meeting via live audio webcast online. Shareholders and duly appointed proxyholders can attend the meeting online at https://meetnow.global/M22JGYZ, where they can participate, vote, or submit questions during the Meeting's live webcast. The Meeting is being held for the following purposes:

(a) to receive the financial statements of the Corporation for the fiscal year ended December 31, 2024, together with the report of the auditors thereon;
(b) to fix the number of directors of the Corporation for the ensuing year at five (5);
(c) to elect the directors of the Corporation for the ensuing year;
(d) to appoint the auditors of the Corporation to hold office until the next annual meeting of the Shareholders and authorize the directors to fix their remuneration; and
(e) to transact such other business as may properly come before the Meeting or any adjournments thereof.

The accompanying management information circular (the "Circular") provides additional information relating to the matters to be dealt with at the Meeting and forms part of this notice. The Circular also provides the required information as to how Shareholders and proxyholders can register for, and access and participate at, the Meeting.

Only Shareholders of record at the close of business on May 30, 2025 (the "Record Date") will be entitled to vote at the Meeting and, subject to certain exceptions, no Shareholder becoming such after the Record Date will be entitled to receive notice of and vote at the Meeting or any adjournment thereof or to be treated as a Shareholder of record for purposes of such other action.

Electronic copies of this notice, the Circular and other Meeting materials may be found on the Corporation's profile on the System for Electronic Document Analysis and Retrieval+ at www.sedarplus.ca.

The Meeting will be hosted online by way of a live webcast at https://meetnow.global/M22JGYZ. Shareholders will not be able to attend the Meeting in person.

Shareholders who have their names and addresses recorded in the Corporation's share register ("Registered Shareholders"), duly appointed proxyholders and shareholders who beneficially own shares that are registered in the name of an intermediary ("Non-Registered Shareholders") will be able to virtually attend the Meeting, ask questions and vote in "real-time".

The Corporation encourages Registered Shareholders and Non-Registered Shareholders who have duly appointed themselves as proxyholders to participate actively in the Meeting, to vote and ask questions.

Registered Shareholders, duly appointed proxyholders, and Non-Registered Shareholders who appoint themselves as a proxyholder can participate in the Meeting by following the instructions below, before the start of the Meeting. See also "Proxy Information" in the Circular.

• Registered Shareholders:
  Clicking "Shareholder" and entering the 15-digit Control Number located on the form of proxy or in the email notification you received.

• Duly appointed proxyholders and Non-Registered Shareholders who appoint themselves as a proxyholder:
  Clicking "Invitation" and entering the Invite Code to be provided by Computershare after June 26, 2025.

Without an Invite Code, proxyholders will not be able to attend and vote at the Meeting.

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SIGMA LITHIUM

Non-Registered Shareholders who have not appointed themselves as proxyholders may attend the Meeting as guests, by clicking "Guest" and completing the online form. Guests will not be able to vote or ask questions at the Meeting.

It is important that you are connected to the internet at all times during the Meeting in order to vote when balloting commences. The Corporation recommends that attendees log into the Meeting platform at least thirty minutes before the Meeting begins. Attendees are entirely responsible to ensure internet connectivity during the Meeting and that all internal network security protocols (such as firewalls or VPN connections) that may block access to the Meeting platform are disabled to allow the attendee to attend the Meeting. Attendees will also need to have the latest version of Chrome, Safari, Edge or Firefox. Note Internet Explorer is not a supported browser. Note that if connectivity is lost once the Meeting has commenced, there may be insufficient time to resolve the connectivity issue before voting polling is completed. Therefore, Shareholders should consider voting in advance or by proxy, so that all votes will be counted in the event of any technical difficulties.

In order to participate online, Registered Shareholders must have a valid 15-digit Control Number and proxyholders must have received an email from Computershare Investor Services Inc. ("Computershare") containing an Invite Code.

Registered Shareholders who wish to appoint a proxyholder are required to complete, date and execute the form of proxy and submit to Computershare either in person, or by mail or courier, to 100 University Avenue, 8th Floor, Toronto, Ontario, M5J 2Y1, or via the internet at www.investorvote.com. The proxy must be deposited with Computershare by no later than 11:00 a.m. (Toronto time) on June 26, 2025, or if the Meeting is adjourned or postponed, not less than 48 hours, excluding Saturdays, Sundays and statutory holidays, before the commencement of such adjourned or postponed Meeting. If a Shareholder who has submitted a proxy attends the Meeting via the webcast and has accepted the terms and conditions when entering the Meeting online, any votes cast by such Shareholder on a ballot will be counted and the submitted proxy will be disregarded. Registered Shareholders must carefully follow the instructions contained in the section "Proxy Information" of the Circular.

After submitting the form of proxy, as an additional and required step, Registered Shareholders will need to register their proxyholders with Computershare at http://www.computershare.com/SigmaLithium no later than 11:00 a.m. (Toronto time) on June 26, 2025 and provide Computershare with their proxyholder's contact information at the "Appointee Information" section on the website indicated above, so that Computershare may provide the proxyholder with an Invite Code via email.

An intermediary holding common shares on behalf of a Non-Registered Shareholder has the right to appoint the Non-Registered Shareholder as a proxyholder to attend and act on their behalf at the Meeting. After submitting the Non-Registered Shareholder voting instruction form, the intermediary must register the Non-Registered Shareholder with Computershare at http://www.computershare.com/SigmaLithium to receive the Invite Code that will enable the Non-Registered Shareholder to participate actively at the Meeting, voting, and asking questions. Non-Registered Shareholders should carefully follow the instructions contained in the section "Proxy Information" of the Circular.

FAILURE TO REGISTER THE PROXYHOLDER WITH COMPUTERSHARE WILL RESULT IN THE PROXYHOLDER NOT RECEIVING AN INVITE CODE TO PARTICIPATE IN THE MEETING. WITHOUT AN INVITE CODE, PROXYHOLDERS WILL NOT BE ABLE TO VOTE AT THE MEETING.

Shareholders are reminded to review the Circular before voting.

DATED at São Paulo, Brazil this 30th day of May, 2025.

BY ORDER OF THE BOARD OF DIRECTORS of Sigma Lithium Corporation

(signed)
"Ana Cristina Cabral"
Co-Chair and Chief Executive Officer

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