Multiple Listing Service or MLS is a brokerage listing syndication service. There are hundreds of regional organizations supported by real estate broker membership that support the listing of properties and reciprocal access to listings, listing status and market data. Services such as Zillow and Redfin access data feeds from many MLS organizations in order to display listings and accurate statuses on their site. Bright MLS, serving the mid-Atlantic region, is an example of an MLS. Multiple Listing Service® or MLS® are registered trademarks of the National Association of REALTORS®.