About CMBS Medical Business Services California Medical Business Services, LLC, is a national management services organization (MSO). We offer a wide range of services, each with the objective of providing our client partners with a sound basis for making important medical practice management decisions. We currently provide revenue cycle management for charges in excess of $250 million per year. We are a uniquely structured organization; large enough to understand the challenges you face and offer a variety of services to combat those challenges. We are also small enough to address questions in a timely manner and develop one to one relationships with our clients.