Notice of Annual Meeting of Shareholders Management Information Circular Friday, May 1, 2020 AltaGas Ltd. – 2020 Management Information Circular March 12, 2020 Dear Fellow Shareholders: Evolution of our Governance and Leadership Sound governance and strong leadership are core to executing our strategy and delivering sustained value for our stakeholders. We are committed to the ongoing pursuit of strong and effective governance practices which is central to our performance. We look to continually enhance how we operate to ensure that our governance approach incorporates evolving global best practices and our Board and leadership team represents the right mix of background, experience and diversity of perspectives. In 2018, AltaGas underwent a significant transformation with the acquisition of WGL Holdings, Inc. and its regulated gas utility business, and the divestiture of a number of non-core assets. To position the company for future success, we appointed three new directors, including myself, to add complementary competencies to our Board to match our evolving business. On April 1, 2019, after celebrating the company’s 25th anniversary, David Cornhill, AltaGas’ founder and then Chairman, stepped down and I transitioned into the Chair role. David remains on our Board as a director, allowing us to retain his experience, insights and institutional knowledge and build upon the strong relationships and trust he has fostered over the years within the communities in which we operate, including those with Canada’s Indigenous Peoples, and with our business partners. Our succession planning continues to be an area of focus for the Board as we strive to strike a balance between continuity of experience and fresh perspectives to meet the evolving needs of our business. Most recently, the Board appointed two new independent directors, Linda Sullivan and Nancy Tower, who together bring over 50 years of utilities experience, along with strong financial backgrounds and senior executive officer experience. As part of this Board transition, Daryl Gilbert has announced that he is not standing for re-election and will retire following this meeting. We would like to thank Daryl for his substantial contributions, valuable insights and his commitment and dedication as a director as AltaGas has grown and evolved during his tenure. 2019 also brought significant changes to our leadership team. With our new President and Chief Executive Officer Randy Crawford at the helm for his first full year, we undertook several initiatives designed to align teams across the enterprise. His leadership and vision for the company have allowed us to refocus on operational excellence in our Utilities and Midstream businesses and regain our financial strength. As part of our leadership evolution, we welcomed a new Executive Vice President and Chief Financial Officer, James Harbilas, whose deep background in both energy and utilities and ability to build and transform functions and teams is proving to be invaluable as we refocus the company for the future. We also welcomed Donald “Blue” Jenkins to AltaGas as Executive Vice President and President, Utilities and President, Washington Gas, to begin implementing additional organizational alignments to optimize our operations and better position us to achieve our strategy. In connection with Blue’s appointment, Colleen Starring was promoted to Senior Vice President and Chief Operating Officer, Utilities and Washington Gas. Colleen has a proven track record of execution, outstanding operations and commercial skills and an unparalleled understanding of our Utilities business. These changes to our governance and leadership structure have directly contributed to our business success over the last year and will enable us to deliver sustained value to our stakeholders going forward. Year in Review In 2019, we successfully delivered on several substantial financial and operating priorities to execute our strategy and position AltaGas as a leading North American energy infrastructure company that connects natural gas and natural gas liquids to domestic and global markets. We successfully executed $2.2 billion of non-core asset sales, which substantially improved our financial health by de-levering our balance sheet. These improved financials allowed us to maintain our investment grade credit rating and regain the financial flexibility needed to pursue our many organic growth opportunities. With the acquisition of WGL Holdings, Inc. completed, we advanced our transformation by integrating teams and functions across the business to capitalize on cost efficiencies and improve operational performance. We completed several key infrastructure projects that will drive future growth across our Utilities and Midstream businesses, including the Ridley Island Propane Export Terminal (RIPET) on the northwest coast of British Columbia, and the Marquette Connector Pipeline in Michigan. These investments play critical roles in our Utilities and Midstream growth strategies. AltaGas Ltd. – 2020 Management Information Circular Sustainability and Stakeholder Value Our core values reinforce our commitment to integrating strong environmental, health and safety, social and governance performance into every aspect of our business. These values have been engrained in our culture from the early days of our company and support our business strategy by allowing us to be responsive to customer needs, better manage risk, and attract, motivate and retain the talent we need to bring value to the communities we serve. One of our greatest strengths has always been the importance and value we have placed on building relationships with our key stakeholders. We approach these relationships thoughtfully to ensure we respect different views and find mutually-beneficial solutions that generate long-term value. Our approach to relationship building was showcased last year during the grand opening ceremony of RIPET. We gathered together with municipal, provincial and federal government officials, local business and community leaders, representatives from the local Metlakatla and Lax Kw'alaams communities as well as our business partners and customers to celebrate the completion of Canada’s first marine propane export facility off the west coast. By balancing economic priorities with our social and environmental values, we believe we can help meet growing global demands for clean energy, while continuing to deliver sustainable benefits to our stakeholders. Through our commitment to building strong, long-lasting relationships we are applying our operational excellence model to ensure we are making a positive social impact. We invite you to learn more about our approach to ESG by reviewing the disclosure in the sustainability section of the proxy circular or downloading our ESG Report from our website at https://esg.altagas.ca/. Looking Forward With our 2019 priorities successfully executed, we enter 2020 on significantly stronger financial footing with a sharper focus on driving results and capturing the significant growth opportunities within our core businesses. Our steady and predictable Utilities business and high-growth integrated Midstream assets provide a strong foundation to deliver attractive risk-adjusted returns. Our people are the heart of AltaGas and key to delivering operational excellence across our company. We have a skilled and dedicated team in place, and we are confident we will continue to deliver long-term value for our stakeholders. Shareholder Meeting As a company deeply committed to the health and safety of our communities, employees, shareholders and all of our other stakeholders, this year AltaGas will hold its annual meeting in a virtual format. As part of our corporate social responsibility and our preparedness plans in response to COVID-19, we believe hosting a virtual meeting is in the best interests of all stakeholders. The virtual meeting will be conducted via live audio webcast commencing at 1:00 p.m. (MDT) on May 1, 2020. Shareholders will have an opportunity to participate at the annual meeting online regardless of their geographic location. As a Shareholder, you have the right to participate in and vote your shares at the meeting. We encourage you to participate in the virtual annual meeting. The circular includes important information and detailed instructions on how to participate. If you are unable to attend the meeting, we encourage you to complete the form of proxy or, if applicable, voting instruction form, and return it within the time frames indicated on such forms so that your vote is counted at the meeting. This proxy circular contains important details about the meeting, the items of business to be considered and how you can vote, so please take some time to read the proxy circular before you vote your shares. Information concerning AltaGas’ consolidated financial and operational performance for the financial year ended December 31, 2019 is available on AltaGas’ website at www.altagas.ca and on SEDAR at www.sedar.com. Thank you for your ongoing support. We look forward to your participation at our virtual meeting. Sincerely, Pentti Karkkainen AltaGas Ltd. – 2020 Management Information Circular NOTICE OF THE ANNUAL MEETING OF SHAREHOLDERS When Items of business Friday, May 1, 2020 at 1:00 p.m. (MDT) At the meeting, shareholders will be Where asked to: Virtual only Meeting 1. receive the consolidated financial via live audio webcast online at https://web.lumiagm.com/190340102 statements for the year ended As part of our