Local associations operate in a variety of ways to suit communities and markets with differing service, scale and governance requirements. Some markets are best served by member-focused organizations that concentrate on advocacy, education and member benefits while others require an organization that also provides and governs the market’s listing infrastructure.

Size, historical governance arrangements, the costs and technical demands of running a multiple listing service and recent legal and regulatory pressures have pushed associations to specialize, consolidate or regionalize so they can deliver the right mix of policy, data and operational capacity for members. Structural factors are also what drive some associations to remain membership-only, while others take on a heavier role of operating a listing service. 

That distinction translates into two common types: 

Association Only entities are member-owned, nonprofit Realtor trade organizations that focus on advocacy, professional standards, education, networking and member services for a local or state market. They do not run an MLS themselves but participate in one operated by a separate entity. 

Combined Association & MLS entities combine those same member services with responsibility for the listing system. They own or run the MLS database, set governance and market rules and provide subscriber and technical services to users of the system. MLS operators can be local or regional and differ by ownership model, a distinction that materially affects governance, data access and how market rules are made and enforced.