AltaGas Ltd. — Proxy Solicitation & Information Statement 2025

Mar 25, 2025

AltaGas

Computershare

8th Floor, 100 University Avenue

Toronto, Ontario M5J 2Y1

www.computershare.com

Security Class

Holder Account Number

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Form of Proxy - Annual and Special Meeting of AltaGas Ltd. Shareholders to be held on Thursday, May 1, 2025

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

Notes to proxy

1. Every shareholder has the right to appoint some other person or company of their choice, who need not be a shareholder of AltaGas, to attend and act on their behalf at the meeting or any adjournment or postponement thereof. If you wish to appoint a person other than the persons whose names are printed herein, please write the name of your chosen proxyholder in the space provided (see reverse) and follow the instructions below the box.
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 this proxy is not dated, it will be deemed to bear the date the form was received by or on behalf of AltaGas.
5. The shares 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 Management Nominees (see reverse) are appointed proxyholders, this proxy will be voted as recommended by Management.
6. The shares 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 and, if the holder has specified a choice with respect to any matter to be acted on, the shares will be voted accordingly.
7. This proxy confers discretionary authority in respect of amendments or variations to matters identified in the Notice of Meeting or other matters that may properly come before the meeting or any adjournment or postponement thereof.
8. This proxy should be read in conjunction with the documentation provided by Management, including the management information circular dated March 6, 2025.

Poxies submitted must be received by 1:30 PM, MDT, on Tuesday, April 29, 2025 (or 48 hours before any adjournment of the 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 proxy.

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

021TGE

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Appointment of Proxyholder

I / We, being shareholder(s) of AltaGas Ltd., hereby appoint: Vern Yu, President and Chief Executive Officer, or James Harbilas, Executive Vice President and Chief Financial Officer, or Karen Uehara, Executive Vice President and Chief Legal Officer.

OR

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

If completing the appointment box above and your appointee intends on attending the meeting virtually, you MUST return your proxy by mail or by internet at www.investorvote.com and ALSO go to www.computershare.com/altagas and provide Computershare with the name and email address of the person you are appointing by 1:30 pm MDT on April 29, 2025. Computershare will use this information ONLY to provide the appointee with a username to gain entry to the virtual meeting. This username will allow your proxyholder to log in, ask questions and vote in real-time at the virtual meeting. Without a username, your proxyholder will only be able to log in to the meeting as a guest and will not be able to ask questions or vote.

As my/our proxyholder with full power of substitution to attend, act and to vote for and on behalf of the shareholder in accordance with the following direction (or if no directions have been given, as the proxyholder sees fit) and all other matters that may properly come before the Annual and Special Meeting of shareholders of AltaGas Ltd. (the "Company") to be held online at https://meetings.lumiconnect.com/400-841-462-038 using the password "altagas2025" (case sensitive) on May 1, 2025 at 1:30 pm MDT and at any adjournment or postponement thereof (the "Meeting").

VOTING RECOMMENDATIONS ARE INDICATED BY HIGHLIGHTED TEXT OVER THE BOXES.

1. Appointment of Auditors

Appoint Ernst & Young LLP as auditors of the Company and authorize the directors of the Company to fix Ernst & Young LLP's remuneration in that capacity.

2. Election of Directors

☐ FOR all nominees listed below
☐ AGAINST all nominees listed below

OR vote for individual nominees below

	For	Against		For	Against		For	Against
01. Victoria A. Calvert	☐	☐	05. Cynthia Johnston	☐	☐	09. Nancy G. Tower	☐	☐
02. David W. Cornhill	☐	☐	06. Pentti O. Karkkainen	☐	☐	10. Vernon D. Yu	☐	☐
03. Jon-Al Duplantier	☐	☐	07. Phillip R. Knoll	☐	☐
04. Derek W. Evans	☐	☐	08. Angela S. Lekatsas	☐	☐

3. Amendment to Option Plan

Approve an amendment to the Company's option plan to set a fixed maximum number of common shares that may be issued on the exercise of options, as described in the management information circular dated March 6, 2025.

4. Executive Compensation

Advisory vote to approve the Company's approach to executive compensation, as described in the management information circular dated March 6, 2025.

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)

D D I M M I Y Y

Signing Capacity

Interim Financial Statements – Mark this box if you would like to receive Interim Financial Statements and accompanying Management's Discussion and Analysis by mail.

☐

Annual Financial Statements – Mark this box if you would NOT like to receive the Annual Financial Statements and accompanying Management's Discussion and Analysis by mail.

☐

If you are not mailing back your proxy, you may register online to receive the above financial report(s) by mail at www.computershare.com/mailinglist.

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