If one of the named purchasers on the protected buyer list signs a contract to buy your property within a certain number of days after the expiration of the listing agreement, the original listing agent is eligible for commission according to the compensation terms set forth in the listing agreement.
The terms of a protected buyer list are contained within your listing agreement. Typical terms include the number of allowable names, how soon the listing agent must send you the list after the listing agreement expires, and how much time the listing agent has to procure a signed contract from one of the buyers on the list.
The purpose of a protected buyer list is to ensure that your current listing agent remains incentivized to procure offers from the most serious prospective purchasers who viewed your home during the term of the listing agreement.