01SXCC 安大略省多倫多大學大道100號8樓M5J 2Y1 www.computershare.com Fold Fold Form of Proxy-AltaGas Ltd.股東年會和特別大會將於4月29日(星期五)舉行2022 此委託書由AltaGas Ltd.管理層徵集並代表AltaGas Ltd. 徵集。 ·請訪問以下網站： www.investorvote.com 使用互聯網進行投票 。 ·使用按鍵電話撥打下面列出的號碼。 使用電話進行投票 。 如果您通過電話或互聯網進行投票，請勿郵寄此委託書。 郵寄投票可能是以公司名義持有的證券或代表其他個人投票的證券的唯一方法。 郵寄投票或Internet投票是持有人可以指定除此委託書背面指定的管理層提名人以外的其他人作為代理持有人的唯一方法。 您可以選擇上面概述的兩種投票方法之一來投票此委託書。 要通過電話或Internet投票，您需要提供下面列出的控制編號。 1.每個股東都有權指定他們選擇的其他人或公司(不必是AltaGas的股東)出席會議或任何延期或延期會議並代表他們行事。如果您希望指定的人不是打印在此的人，請在所提供的空白處填寫您選擇的受託管理人的姓名(請參見反面)，並遵循下面的説明。 2.如果股份是以多個所有者的名義登記的(例如，共同所有人、受託人、遺囑執行人等)，則所有登記的人都應在本委託書上簽名。如果您代表公司或其他個人投票，則必須在本委託書上簽名，並註明簽名能力, 您可能需要提供證明您有權簽署本委託書的文件。 3.本委託書的簽名方式應與委託書上的名稱完全相同。 4.如果本委託書未註明日期，則將被視為帶有AltaGas收到或代表AltaGas收到表格的日期。 5.本委託書所代表的股份將按持有人的指示投票，但是，如果未就任何事項作出指示，且管理層被指定為代理人，本委託書將按照管理層的建議進行表決。 6.本委託書所代表的股份將根據持有人的指示，在可能要求進行的任何投票中投贊成票、棄權票或反對票。如果持股人已就要採取行動的任何事項作出具體選擇，股份將據此投票。 7.本委託書授予對會議通知中確定的事項的修改或變更的自由裁量權，或在會議或其任何休會或延期之前適當提交的其他事項的酌處權。 8.本委託書應與管理層提供的文件一起閲讀，包括3月10日的管理信息通告，2022. 代理備註 ·您可以通過訪問 www.investorcentre.com以電子方式註冊接收未來的安全持有人通信 。 要以電子方式接收文檔 ·智能手機？ 現在掃描二維碼 進行投票。 。 控制號碼 使用電話或互聯網投票一週7天24小時！ 提交的代理必須在MDT 4月27日星期三下午1：00之前收到, 2022 (或任何休會前48小時)。 若要虛擬出席 會議 ·您可以通過訪問此代理背面提供的URL來虛擬 出席會議。 安全類 持有者帳號 1-866-732-Vote(8683)

331804 Fold Fold . AR2 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. 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. 01SXDC Authorized Signature(s) – This section must be completed for your instructions to be executed. 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 Management Nominees are appointed proxyholders, this Proxy will be voted as recommended by Management. DD / MM / YY . Signature(s) Date Appointment of Proxyholder Print the name of the person you are appointing if this person is someone other than the Management Nominees listed herein. I / We, being shareholder(s) of AltaGas Ltd., hereby appoint: Randall L. Crawford, President and Chief Executive Officer, or failing this person, James Harbilas, Executive Vice President and Chief Financial Officer. OR 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 via live audio webcast online at https://web.lumiagm.com/464137331 using the password “altagas2022” (case sensitive) on April 29, 2022 at 1:00 PM MDT and at any adjournment or postponement thereof (the “Meeting”). VOTING RECOMMENDATIONS ARE INDICATED BY HIGHLIGHTED TEXT OVER THE BOXES. 2. Election of Directors Withhold For Withhold For Withhold For FOR all nominees listed below WITHHOLD FROM VOTING for all nominees listed below OR vote for individual nominees below 01. Victoria A. Calvert 02. David W. Cornhill 03. Randall L. Crawford 05. Robert B. Hodgins 06. Cynthia Johnston 07. Pentti O. Karkkainen 09. Linda G. Sullivan 10. Nancy G. Tower 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. Withhold For 3. Unallocated Options Approve the unallocated options under the Company’s option plan, as described in the management information circular dated March 10, 2022 (the “Circular”). Against For 04. Jon-Al Duplantier 08. Phillip R. Knoll If completing the appointment box above, 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 1:00 p.m. MDT on April 27, 2022. 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. 4. Executive Compensation Advisory vote to approve the Company’s approach to executive compensation, as described in the Circular. ALAQ