Listing Clients Should Have a Copy of Their CMA – Not Prospects
Think about all the companies with which you do business. We're talking about for services like telephone, utilities, and all the places you shop or where you consume services. They all have their own policies as to how they'll do business with you.
The muffler shop has a policy that customers cannot be in the shop area for insurance reasons. The electric company requires a shut-off request to be in writing. There are hundreds of quick examples if you think about it.
As a real estate agent or broker, you are an independent business and have a right, indeed an obligation, to have policies under which you do business. One of those should be that you do not provide your written CMA documents to anyone other than listing clients.
You can say it nicely, but say something like "We have a policy that we do give complete CMA copies only to listing clients. If you need me to refresh your memory about any of our CMA discussions today, please call me. Should you list with us, you'll be provided the CMA copy with your copy of the listing agreement.
Your expertise and resources were used to produce the CMA, and you've used it to advise the seller prospect as to listing price possibilities. Your obligation ends there. There's no reason to leave it so that they can go FSBO, or use it to prompt other, less professional, agents to come up with their listing price recommendations from your data.