Which type of contract addresses the payment of a retainer?

A listing agreement is a contract between a property owner and a real estate agent or broker that outlines the terms under which the agent will represent the owner in the sale or lease of the property. This type of agreement typically specifies the payment structure for the agent's services, including the payment of a retainer fee or a commission based on the final sale price.

In contrast, a purchase contract primarily focuses on the terms of the sale of a property, including the price, contingencies, and details of the transaction, rather than on compensation for agents. A counteroffer is a response to an initial offer that modifies the terms and is not concerned with retaining fees. An addendum is an additional document that modifies or adds to an existing contract but does not primarily address payment structures.

Therefore, the listing agreement is the correct type of contract that specifically addresses the payment of a retainer to the real estate agent or broker.