Although both agents and managers function similarly at times, a simple distinction between the two can be made by observing that agents are the only entities authorized to negotiate and service employment contracts, while managers primarily focus on career direction (i.e. advising clients on the presentation of artistic talents, introducing clients to agents and casting directors, etc..) and the overall management of the artist's career and business.
Unlike agents, SAG-AFTRA does not franchise managers. Therefore, SAG-AFTRA cannot regulate the fees they charge--such fees are subject to State law. Although your Local office may be able to answer general questions, SAG-AFTRA cannot arbitrate or resolve disputes involving managers.
In some states, persons who secure employment must be licensed as talent agents by the city or state in which they are doing business. There are sometimes exceptions for other categories of professionals (e.g. attorneys), and certain fields of work are granted exemptions under various state laws (e.g., Sound Recordings in California).
Always do your homework and investigate the reputation of a manager, talk with other colleagues and check out references before you sign with an unregulated entity. A good manager should understand your concerns. SAG-AFTRA does have a roster of affiliated managers, however. They can be found here: http://www.sagaftra.org/managers
For additional information, please visit https://www.sagaftra.org/professionalrepresentatives