A consulting firm or simply consultancy is a professional service firm that provides expertise and specialised labour for a fee, through the use of consultants. Consulting firms may have one employee or thousands; they may consult in a broad range of domains, for example, management, engineering, and so on.
Management consultants, in particular, typically work with company executives and provide them with generalists and industry-specific specialists, known as subject-matter experts, usually trained in management or in business schools. The deliverable of a management consultant is usually recommendations for achieving a company objective, leading to a company project.