National Association of Realtors

The NAR governs the hundreds of local Multiple Listing Services (MLSs) which are the information exchanges used across the nation by real estate brokers. (However, many MLSs are independent of NAR, although membership is typically limited to licensed brokers and their agents; MLSPIN is an example of one of the larger independent MLSs in North America.)

Through a complicated arrangement, NAR sets the policies for most of the Multiple Listings Services, and in the late 1990s, with the growth of the Internet, NAR evolved regulations allowing Internet Data Exchanges (IDX) whereby brokers would allow a portion of their data to be seen on the Internet via brokers' or agents' websites and Virtual Office Websites (VOW) which required potential buyers to register to obtain information.

These policies allowed participants—whether they were individual one-person brokers or large regional companies—to limit access to some or all of the MLS data by individual brokers (whether they were brokers operating solely on the Internet or local competitors). In 2005, this prompted the Department of Justice to file an antitrust lawsuit against NAR alleging its MLS rules regarding these types of limitations on the display of data were the product of a conspiracy to restrain trade by excluding brokers who used the Internet to operate differently from traditional brick-and-mortar brokers. (For a description of the DOJ action, see Antitrust Case filings for U.S. vs. National Association of Realtors.) Meanwhile, various real estate trends such as expanded consumer access and the Internet are consolidating existing local MLS organizations into larger and more statewide or regional MLS systems, such as in California and Virginia/Maryland/Washington, D.C.'s Metropolitan Regional Information Systems.

In response to the case, NAR had proposed setting up a single Internet Listing Display system which would not allow participants to exclude individual brokers (whether of a bricks-and-mortar type or solely internet-based) but require a blanket opting out of display on all other brokers' sites. This system became the IDX system. Although IDX allows the public to view MLS listings, it still requires the listing brokerage information to be placed on the listing every place it appears (brokers legally "own" the listings of their brokerage), to prevent misrepresentation of the listing information, and to place accountability for the information on the broker as the law dictates.

Antitrust lawsuits

In 2005, the United States Department of Justice filed a formal complaint against the National Association of Realtors for violating Section 4 of the Sherman Antitrust Act. The complaint sought to enjoin the National Association of Realtors "from maintaining or enforcing a policy that restrains competition from brokers who use the Internet to more efficiently and cost effectively serve home sellers and buyers, and from adopting other related anticompetitive rules.

The DOJ challenged NAR's MLS rules that inhibited competition from Internet-based brokers. On November 18, 2008, the Court entered a Final Judgment approving a settlement against NAR.

Under the Final Judgment, the NAR agreed to the policies challenged by the United States and replaced those policies with rules that do not discriminate against brokers who use the Internet to provide low-priced brokerage services to consumers.

In 2012, American Home Realty Network, Inc., the operator of NeighborCity, filed antitrust counterclaims in response to a pair of copyright lawsuits, alleging that the "copyright lawsuits filed against it by two multiple listing services with financial backing from the National Association of Realtors are part of a concerted effort by NAR to drive the company out of business and eliminate it as a provider of services to real estate brokers." The counter-claims also allege that the copyrights asserted were never properly registered. In the Minnesota case, which recites claims against the NAR but does not directly name the NAR as a counter-defendant, AHRN filed a second amended counterclaim adding Edina Realty and Home Services of America as Counter-Defendants in the antitrust and unfair competition claims. Edina Realty is a subsidiary of HomeServices of America, Inc., a Berkshire Hathaway company, which owns real estate brokerage firms in states across the country, including Minnesota, Maryland, North Carolina, Georgia, Washington, Oregon, Arizona, Rhode Island, Connecticut, Iowa, Nebraska, Ohio, Illinois, Kansas, South Carolina, Missouri, Pennsylvania, Indiana, Kentucky, Alabama, and California. Earlier in 2012, the mid-Atlantic multiple listing service Metropolitan Regional Information Systems, Inc. (MRIS) and St. Paul, MN-based Regional Multiple Listing Service of Minnesota Inc. (NorthstarMLS) filed copyright claims against NeighborCity. The National Association of Realtors said it would provide financial support for NorthstarMLS and MRIS legal expenses.

Another lawsuit was filed in March 2019 challenging NAR's compensation policies which require all member brokers demand blanket, non-negotiable buyer-side commission fees when listing a home on a Multiple Listing Service (MLS).

Burnett et al v. National Association of Realtors et al

On October 31, 2023, a federal civil jury found that the NAR had conspired to inflate commissions paid to home-buyers' real estate agents, and determined that NAR and its codefendants owed damages of almost US$1.8 billion. The lawsuit, Burnett et al v. National Association of Realtors et al, was heard in the U.S. District Court for the Western District of Missouri in Kansas City, and involved allegations of violations of federal and state antitrust laws by the NAR, HomeServices of America, Keller Williams Realty, Anywhere Real Estate (parent of Coldwell Banker, Century 21 Real Estate, and Sotheby's International Realty) and Re/Max. Anywhere and Re/Max had previously settled their liability and agreed to pay lesser damages, leaving NAR, HomeServices and Keller Williams to defend the suit at trial. Upon announcement of the verdict and before final judgment was entered, NAR and HomeServices stated their intention to appeal, and Keller Williams was considering doing so. In March 2024, NAR agreed to settle for a reduction of damages to US$418 million, eliminating its rules on commissions, and waiving its right to appeal. As a result of the settlement, starting August 2024, buyers’ agents commission fees are not allowed to be advertised and buyers must sign a contract with their agent before seeing properties together. The Wall Street Journal reported the settlement is expected to reduce real estate commissions, force some agents out of the industry, and lead to a decline in NAR’s membership.