CHYY Development Group Limited CHYY Development Group Limited (8128.HK), an investment holding company listed on the Hong Kong Stock Exchange's GEM board, engages in the research, development, promotion, and commercialization of shallow geothermal energy systems as alternative energy solutions for building heating applications primarily in the People's Republic of China. The company operates through four main segments—Shallow Geothermal Energy, Air Conditioning/Shallow Geothermal Heat Pump, Property Investment and Development, and Securities Investment and Trading—offering planning and design of renewable energy systems; supply and intelligent manufacturing of geothermal energy equipment; engineering construction, installation, operation, and maintenance of energy systems; trading of air conditioning and shallow geothermal heat pump products; property investment, development, and management; securities trading and other investments; and technical support services. Incorporated in 2000 and headquartered at Chung Hing Commercial Building in Central, Hong Kong, it targets commercial and residential customers in mainland China seeking sustainable heating alternatives. In August 2022, the company changed its name from China Geothermal Industry Development Group Limited to its current name, aligning with strategic rebranding efforts; more recently, it implemented an exclusive agency system for HYY geothermal heat pump high-efficiency clean heating projects, pursued market expansion as a core driver, and conducted share buybacks including tranches in 2024 and 2025 to enhance shareholder value.