If a REALTOR® participates in a regional MLS owned by two or more shareholder boards, which board is responsible for professional standards enforcement with respect to those REALTOR® members who participate in the MLS but do not hold membership in one of the shareholder boards?

Professional standards enforcement would be the responsibility of the board through which the REALTOR® obtained participation rights. Participation in a regional MLS is only available through one of the shareholder (or signatory) boards. In other words, a REALTOR® cannot obtain direct access to the MLS through the regional entity. Rather, REALTORS® must sign an MLS participation agreement with one of the shareholder (or signatory) boards which establishes their agreement to submit to ethics and arbitration requests filed with the board from which the REALTOR® obtained MLS access but is not a member.

Source: TAR