San Jose, California | November 2026

After 120 years of proudly serving Silicon Valley and the greater San Francisco Bay Area, O.C. McDonald Company, Inc. announces the transition of its business operations to ATS Mechanical, effective October 26, 2026.

Founded in 1906, O.C. McDonald has built a lasting legacy of craftsmanship, integrity, innovation, and exceptional service. For generations, our dedicated employees, loyal customers, and trusted business partners have been the foundation of our success.
As part of this transition, ATS Mechanical has acquired the operating assets of O.C. McDonald and assumed responsibility for ongoing operations, projects, and service activities. This next chapter is designed to provide continuity of service while building upon the relationships and reputation O.C. McDonald has established over more than a century.

We extend our deepest gratitude to the employees, customers, contractors, suppliers, and community partners who have been part of the O.C. McDonald story. Your trust and support have made our 120-year legacy possible.
While the O.C. McDonald name concludes its remarkable chapter in Bay Area construction history, our commitment to the people and partnerships that built this company continues through ATS Mechanical.