M
ost home sales in the US take place through a multiple listing service (MLS), a regional database where real estate agents share information about properties for sale. The MLS has been making headlines lately due to changes implemented after a major legal settlement over real estate commissions.

    The first known MLS was developed in 1885 in San Diego, where the local real estate board would update listings twice daily and distribute them to members through runners. Similar systems were adopted by Cleveland and Chicago, but at that time, anyone could declare themselves a real estate broker without education requirements or state licensing laws.

    The MLS provided a way for trusted brokers to exchange information and access up-to-date property listings, but it also served as a gatekeeper, excluding Black, Jewish, and female brokers from joining local boards until the 1960s. The National Association of Real Estate Boards pushed for wider adoption in the 1920s, and the services exploded during the post-war housing boom of the 1950s.

    Initially, listings were printed on notecards and compiled into big books, which agents would update once or twice a month. With the advent of computer terminals in the late 1970s, agents could search for properties electronically. The internet revolutionized the industry, allowing public access to MLS data through websites like Realtor.com.

    Today, over 500 MLS services operate across the US, most owned by local realtor associations and governed by the National Association of Realtors. This system is unique to North America, where agents can easily search for properties online. In contrast, many European countries require buyers to visit storefronts or drive around to find available listings.

    A new International MLS Forum aims to bring this US model to other parts of the world, where multiple listings are often fragmented and chaotic.