http://revach.net/article.php?id=2286

Section: Halacha   Category: Tshuvos
Rav Vosner: When A Small Real Estate Deal Gets Big, Is The Broker Shortchanged?
A real estate agent is hired to find a rentor for someone’s apartment.  The rentor is found but during the negotiations the rentor and the owner decide that instead of renting the apartment the rentor will purchase it outright.  The agent sees before him a windfall profit since the commission for a sale is much higher than for a rental.  However the owner would like to pay him only the “rental” commission since this is what the agent was hired to do.  Who is right?

Rav Shmuel Vosner (Shevet HaLevi 10:268:2) says that L’Halacha the agent is only entitled to the rental commission.  The reason is that an agent is a Shaliach of the person sending him, in this case the owner.  That owner specifically sent him to find a rentor and only agreed to pay him a rental commission and not a sales commission.  If during the course of his job he brought the owner a greater profit, it was only in a roundabout way because he had no idea that the owner would be interested in selling.  Therefore the owner should definitely give him something extra and be good to him however as far as the commission goes, he would have a hard time making a valid claim for that.

Important Note: We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. Please also understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.