REALTORS® Code of Ethics: Duties to Clients and Customers, Article 1, Standard of Practice 1-12

When entering into listing contracts, REALTORS® must advise
sellers/landlords of:
1) the REALTOR®ʼs company policies regarding cooperation and the
amount(s) of any compensation that will be offered to subagents,
buyer/tenant agents, and/or brokers acting in legally recognized
non-agency capacities;
2) the fact that buyer/tenant agents or brokers, even if compensated
by listing brokers, or by sellers/landlords may represent the
interests of buyers/tenants; and
3) any potential for listing brokers to act as disclosed dual agents,
e.g., buyer/tenant agents.

See entire Code of Ethics HERE