Sigma Lithium — Proxy Solicitation & Information Statement 2025

Jun 2, 2025

SIGMA LITHIUM

Computershare

8th Floor, 100 University Avenue

Toronto, Ontario M5J 2Y1

www.computershare.com

MGXQ 000001

SAM SAMPLE
123 SAMPLES STREET
SAMPLETOWN SS X9X X9X
CANADA

Security Class
COMMON SHARES

Holder Account Number
C99999999999 IND

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Form of Proxy - Annual General Meeting to be held on Monday, June 30, 2025 at 11:00 a.m. (Toronto time)

This Form of Proxy is solicited by and on behalf of Management.

Notes to proxy

1. Every holder has the right to appoint some other person or company of their choice, who need not be a holder, to attend and act on their behalf at the meeting or any adjournment or postponement thereof. If you wish to appoint a person or company other than the Management Nominees whose names are printed herein, please insert the name of your chosen proxyholder in the space provided (see reverse).
2. If the securities are registered in the name of more than one owner (for example, joint ownership, trustees, executors, etc.), then all those registered should sign this proxy. If you are voting on behalf of a corporation or another individual you may be required to provide documentation evidencing your power to sign this proxy with signing capacity stated. If you are voting on behalf of a corporation you are required to provide your name and designation of office, e.g., ABC Inc. per John Smith, President.
3. This proxy should be signed in the exact manner as the name(s) appear(s) on the proxy.
4. If a date is not inserted in the space provided on the reverse of this proxy, it will be deemed to bear the date on which it was mailed to the holder by Management.
5. The securities represented by this proxy will be voted as directed by the holder, however, if such a direction is not made in respect of any matter, and the proxy appoints the Management Nominees listed on the reverse, this proxy will be voted as recommended by Management.
6. The securities represented by this proxy will be voted in favour, or withheld from voting, or voted against each of the matters described herein, as applicable, in accordance with the instructions of the holder, on any ballot that may be called for. If you have specified a choice with respect to any matter to be acted on, the securities will be voted accordingly.
7. This proxy confers discretionary authority in respect of amendments or variations to matters identified in the Notice of Meeting and Management Information Circular or other matters that may properly come before the meeting or any adjournment or postponement thereof, unless prohibited by law.
8. This proxy should be read in conjunction with the accompanying documentation provided by Management.

Proxies submitted must be received 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.

VOTE USING THE TELEPHONE OR INTERNET 24 HOURS A DAY 7 DAYS A WEEK!

To Vote Using the Telephone
- Call the number listed BELOW from a touch tone telephone.
1-866-732-VOTE (8683) Toll Free

To Vote Using the Internet
- Go to the following web site: www.investorvote.com
- Smartphone? Scan the QR code to vote now.

To Receive Documents Electronically
- You can enroll to receive future securityholder communications electronically by visiting www.investorcentre.com.

To Virtually Attend the Meeting
- You can attend the meeting virtually by visiting the URL provided on the back of this document.

If you vote by telephone or the Internet, DO NOT mail back this proxy.

Voting by mail may be the only method for securities held in the name of a corporation or securities being voted on behalf of another individual.

Voting by mail or by Internet are the only methods by which a holder may appoint a person as proxyholder other than the Management Nominees named on the reverse of this proxy. Instead of mailing this proxy, you may choose one of the two voting methods outlined above to vote this proxy.

To vote by telephone or the Internet, you will need to provide your CONTROL NUMBER listed below.

CONTROL NUMBER 23456 78901 23456

MGXQ_PRX_375998/000001/000001/1

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SAM SAMPLE

C9999999999

IND C02

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Appointment of Proxyholder

I/We being holder(s) of securities of Sigma Lithium Corporation (the "Corporation") hereby appoint: Ana Cristina Cabral, or failing this person, Marcelo Paiva (the "Management Nominees")

OR

Print the name of the person you are appointing if this person is someone other than the Management Nominees listed herein.

Note: If completing the appointment box above YOU MUST go to http://www.computershare.com/SigmaLithium and provide Computershare with the name and email address of the person you are appointing. Computershare will use this information ONLY to provide the appointee with an invite code to gain entry to the online meeting.

as my/our proxyholder with full power of substitution and to attend, act and to vote for and on behalf of the holder in accordance with the following direction (or if no directions have been given, as the proxyholder sees fit) and on all other matters that may properly come before the Annual General Meeting of shareholders of the Corporation to be held online at https://meetnow.global/M22JGYZ on Monday, June 30, 2025 at 11:00 a.m. (Toronto time) and at any adjournment or postponement thereof.

VOTING RECOMMENDATIONS ARE INDICATED BY HIGHLIGHTED TEXT OVER THE BOXES.

				For	Against
1. Fix number of Directors at five (5)
It is proposed that five (5) Directors be elected at the Meeting and each will hold office until the next annual general meeting or until their successor is duly elected or appointed.				☐	☐
2. Election of Directors
	For	Against	For	Against	For
01. Ana Cristina Cabral	☐	☐	02. Marcelo Paiva	☐	03. Junaid Jafar
04. Eugênio de Zagottis	☐	☐	05. Alexandre R. Cabral	☐	☐
				For	Withhold
3. Appointment of Auditors
Appointment of Grant Thornton Auditors Independentes Ltda. as Auditors of the Corporation for the ensuing year and authorizing the Directors to fix their remuneration.				☐	☐

Signature of Proxyholder

I/We authorize you to act in accordance with my/our instructions set out above. I/We hereby revoke any proxy previously given with respect to the Meeting. If no voting instructions are indicated above, and the proxy appoints the Management Nominees, this Proxy will be voted as recommended by Management. If you are voting on behalf of a corporation you are required to provide your name and designation of office, e.g., ABC Inc. per John Smith, President.

Signature(s)

Date

DD/MM/YY

Signing Capacity

MGXQ

375998

1 A P D I Z

AR0

99999

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