Announcement PDF Mayfield Group Holdings Limited | ASX:MYG | ABN 57 010 597 672 3 Gidgie Court, Edinburgh SA 5111 Australia | mayfieldgroup.com.au ASX Release 17 March 2026 APPOINTMENT OF CHIEF OPERATING OFFICER Investing in Leadership Capability to Deliver the Next Phase of Growth Highlights: • Andrew Naffin appointed as Chief Operating Officer (COO) of Mayfield Group Holdings, commencing 23 March 2026 • Highly experienced operational executive with 25+ years of leadership across manufacturing, engineering, supply chain transformation and business development at organisations including Schneider Electric, SAGE Automation and SMR Automotive Global • COO role created to integrate and optimise operations as Mayfield scales its three-pillar strategy of Manufacture, Product Solutions and Critical Control and Communications • Appointment reflects the Company’s continued investment in senior leadership capability, as communicated to investors during the recent roadshow • The Company has also made three further senior leadership appointments – Chris Ware as Chief Technology and Innovation Officer, Steve Clark as General Manager Mayfield Industries and Marcus O’Neill as Branch Manager WA Mayfield Industries • Strengthens the executive team as the Company executes on a growing pipeline, integrates two strategic acquisitions, and targets continued revenue and margin expansion Mayfield Group Holdings Limited (ASX: MYG) (“Mayfield” or “the Company”) is pleased to announce the appointment of Mr Andrew Naffin as Chief Operating Officer (COO), effective 23 March 2026. The COO is a newly created role designed to lead Mayfield’s operational functions, integrating manufacturing and services across the Group and driving the Company’s strategic transformation agenda. As Australia’s only ASX-listed pure-play electrical infrastructure manufacturer, Mayfield occupies a unique position in the market. With 90 years of heritage, $114 million Work in Hand, and with two recent acquisitions, the Company requires a dedicated operational leader to coordinate and drive performance across a growing, increasingly complex business. The appointment reflects the Company’s commitment to investing in the senior leadership capability required to sustain exceptional growth. As communicated to investors during the Company’s recent roadshow, investing in the right talent is central to Mayfield’s strategy. The COO role is critical to ensuring the Company integrates and optimises its operations across the three strategic pillars of Manufacture, Product Solutions and Critical Control and Communications, while maintaining the agility and customer focus that has driven 38% revenue growth and 73% EBITDA growth in FY2025. AboutAndrew Naffin Mr Naffin is an accomplished operational executive with over 25 years of leadership experience spanning manufacturing, engineering, project management, supply chain strategy, organisational transformation and business development. He brings a strong track record of building high-performance teams and driving operational excellence across complex, multi- site operations. Most recently, Mr Naffin held the role of Head of Operations at Techno Plas Pty Ltd, where he provided executive leadership in a newly created role to accelerate the company’s growth ambitions. In this role, he designed and implemented additional manufacturing and warehouse locations and led the consolidation and optimisation of acquired businesses. Prior to this, Mr Naffin held senior leadership positions at SAGE Automation as General Manager and General Manager Manufacturing, where he was responsible for the company’s overall advanced manufacturing capability, strategic planning, and the leadership of engineering, project management and digital functions across the SAGE Group of businesses. ASX:MYG | mayfieldgroup.com.au His earlier career included significant leadership roles at Schneider Electric, where he served as South Australia Site Leader (responsible for over 750 staff), HSE Leader Pacific, and held various leadership positions across global supply chain operations. Mr Naffin also held the position of Manufacturing Director and Production and Quality Director Australasia at SMR Automotive Global, where he provided strategic leadership across international manufacturing operations spanning India, Korea and China. Mr Naffin holds a Master of Business Administration from the University of South Australia and a qualification in Mechanical Engineering. He has completed executive development programmes at INSEAD University (Abu Dhabi) in Transformational Leadership and the Innovators Method, Supply Chain Leadership with Schneider Electric (Paris), and the Governors Leadership Foundation programme with the Leaders Institute of South Australia. CEO Commentary Commenting on the appointment, Group CEO Andrew Rowe said: “We are delighted to welcome Andrew Naffin to the Mayfield team as our Chief Operating Officer. Andrew’s depth of experience in manufacturing operations, organisational transformation, and building high-performance teams aligns directly with what we need as we scale the business into its next phase of growth. Mayfield’s people are the foundation of everything we achieve. The quality of our leadership team is what allows us to deliver for customers, drive innovation and ultimately create value for shareholders. Andrew’s appointment significantly strengthens that foundation. As we communicated during our recent roadshow, investing in the right talent and capabilities is central to our strategy. With a $954 million opportunity pipeline, two recent acquisitions to integrate, and strong demand across data centres, renewables, defence and mining, the COO role is critical. Andrew will lead the operational integration of our businesses, drive efficiency and ensure we maintain the customer focus and delivery excellence that sets Mayfield apart in the market.” Further LeadershipAppointments Alongside the COO appointment, Mayfield is pleased to confirm three further senior leadership appointments made as part of a company-wide organisational realignment to enhance efficiency, accountability and collaboration across the Group. Chris Ware – Chief Technology and Innovation Officer (CTIO) Mr Ware has been promoted to the newly created role of CTIO, effective 1st December 2025. In this role, Mr Ware leads Mayfield’s technology, product development and innovation agenda, ensuring Mayfield remains at the forefront of engineering capability and continues to deliver superior solutions to our customers. His promotion ensures dedicated executive focus on Mayfield’s innovation roadmap, new product development and the technology partnerships which are central to the Company’s competitive positioning in high-growth sectors. Steve Clark – General Manager, Mayfield Industries Mr Clark has been promoted to General Manager of Mayfield Industries effective 1st December 2025. Mr Clark’s promotion recognises his proven leadership within the business and his ability to drive results across Mayfield Industries manufacturing operations Marcus O’Neill – Branch Manager WA Mr O’Neill has been promoted to Branch Manager WA at Mayfield Industries effective 5th January 2026. This promotion strengthens our Western Australian operations, enhancing local leadership capability, and supporting our continued focus on customer delivery, safety, and operational excellence. This announcement has been authorised for release by the Board of Directors. FOR MORE INFORMATION, PLEASE CONTACT: Andrew Rowe Managing Director Mayfield Group Holdings Limited T: +61 8 8169 1070 ASX:MYG | mayfieldgroup.com.au About Mayfield Group Holdings Mayfield Group Holdings Limited (ASX: MYG) designs, manufactures and services the critical electrical infrastructure that forms the foundation for Australia's energy systems, data centres, defence installations and essential industrial operations. While the world embraces new technologies, such as solar farms, data centres, electric vehicles, and AI computing, Mayfield builds the fundamental electrical infrastructure that makes them work. Our business is built on a simple truth: nothing happens without power, and power requires reliable, intelligent distribution systems. We don't just participate in Australia's progress; we provide the essential infrastructure foundation that enables it. Operating from advanced manufacturing facilities in Adelaide (26,500m²) and Perth (7,900m²), with service operations across all mainland state capitals, Mayfield delivers integrated solutions through four complementary business units: Mayfield Industries (modular electrical manufacturing), BE Switchcraft (commercial electrical solutions), Power Parameters (critical power equipment and testing) and SMEC Power and Technology (underground mining electrical manufacturing), supported by ATI Australia's communications and control systems capabilities. Our Australian manufacturing provides supply chain security and rapid response capabilities, positioning Mayfield as an experienced and trusted partner that delivers for major contractors, utilities, infrastructure operators, and government entities. For more information, visit: www.mayfieldgroup.com.au