Ambrosi Donahue Congdon is a CPA firm headquartered in Newburyport, Massachusetts, serving business owners, families, and organizations with accounting and tax support. The firm traces its roots to 1974 and describes its work as year-round, collaborative guidance around money, tax, and growth.

Its services include tax services, bookkeeping, audit and assurance, outsourced accounting, FP&A, government billing, indirect rate management, and research and experimentation tax credits. ADC works with small businesses, professional services firms, manufacturers and distributors, individuals, trusts and estates, R&D startups, government contractors, established companies, closely held companies, and growth-stage companies.