Have you heard of any social media marketing company wanting a % of your business?

I will try to make this quick. We sell a product and one of our sales people, who really has done great, has come up with this idea for us to do social media marketing, he wants a percentage of sales because he will really be doing all the work which is fine but he feels we need to hire a social media company that has only been around a year or 2 who is "hungry" to work and will work on commission and who will want 25% of our company as ownership because he thinks they will work harder then anyone else. I have never heard of any social media company wanting ownership of a company they are working with. Have you?

*Mind you this isn't our product, my mom owns the product we just buy it off of her wholesale and sell it. We would be promoting our own website. So he wants to give up a % of our company we are building with a product we don't own.