A settlement reached this week threatens to strike a blow to an established standard of residential real estate: the 6 percent sales commission. It also will change who pays it. The deal, reached after a yearslong court battle initially brought by a group of home sellers in Missouri, calls for the powerful National Association of Realtors, which has long regulated the way U.S. homes are sold, to amend its rules on how Realtors for sellers and buyers are compensated.

In most real estate transactions in the United States, both the seller and buyer have an agent representing them. For decades, there’s been a standard for paying these agents: a commission of between 5 and 6 percent of the home’s sale price, covered by the seller and split between the two agents.

Commission rates are significantly lower in many other countries. In Britain, they are just above 1 percent, while in Singapore, the Netherlands and Denmark, they hover between 2 and 3 percent, according to a study by the investment firm Keefe, Bruyette & Woods. The homeowners who sued in federal court in Missouri said that N.A.R., through its rules on agent compensation, conspired to artificially inflate the commissions paid to real estate agents.

Now those rules are set to change as early as July, pending court approval of the settlement that includes N.A.R.’s agreement to pay $418 million in damages.

There could be more room for negotiation.

Real estate agents argue that commissions have long been negotiable, and the standard 5 to 6 percent is practice rather than precept.

The New York Times