It is the Landlord who pays the Commission--not the property management company. Also, be sure you are entitled to a commission. Brokers (Property Managers) are required to "Co-operate" but are not required to pay the advertised fee/commission if you were NOT considered to be the "Procuring Cause". If your Client spoke to the Landlord/property management prior to your contact you may not have a right to a commission. If your "Client" was really just a "Customer", you were a "Sub-Agent" and possibly not entitled. According Maryland anyway. I usually specify in my listings that "Sub-Agent" compensation is "0%".
Aug 18, 2013