Willdan Group, Inc. engages in the provision of technical and consulting services. It operates through the Energy and Engineering & Consulting segments. The Energy segment offers energy and sustainability consulting services to utilities, public agencies and private industry. The Engineering and Consulting segment provides civil engineering-related construction management, building and safety, city engineering office management, city planning, civil design, geotechnical, material testing and other engineering consulting services. The company was founded in May 1964 and is headquartered in Anaheim, CA.

AECOM engages in the design, manufacture, financing, and operation of infrastructure assets for governments, businesses, and organizations. It operates through the following segments: Americas, International, and AECOM Capital. The Americas segment deals with planning, consulting, architectural and engineering design, construction management, and program management services to public and private clients in the United States, Canada, and Latin America in major end markets such as transportation, water, government, facilities, environmental, and energy. The International segment focuses on planning, consulting, architectural and engineering design services and program management to public and private clients in Europe, the Middle East, India, Africa, and the Asia-Australia-Pacific regions in major end markets such as transportation, water, government, facilities, environmental, and energy. The AECOM Capital segment is involved in investing and developing real estate projects. The company was founded on January 31, 1980 and is headquartered in Dallas, TX.

Tetra Tech, Inc. engages in the provision of consulting and engineering services that focus on water, environment, infrastructure, renewable energy, and international development. It operates through the following segments: Government Services Group (GSG) and Commercial and International Services Group (CIG). The GSG segment offers consulting and engineering services primarily to United States government clients such as federal, state and local, and development agencies worldwide. The CIG segment provides consulting and engineering services to US commercial clients and international clients inclusive of the commercial and government sectors, as well as infrastructure, environmental, engineering, and project management services across Canada, Australia, New Zealand, the United Kingdom, Brazil, and Chile. The company was founded in 1966 and is headquartered in Pasadena, CA.