I dont know about Boston ( All real estate is local....even what you speak of) but, in California, your past sales and earnings will dictate your ability to negotiate. If you are an average producer, you will probably be at the Broker's mercy. Not many brokerages are looking to add average talent yet, are always looking for producers.....unless, of course, they have a business model designed to profit from agents through desk fees, training fees and products which must be purchased from approved suppliers at premium prices. Discussing specifics with regard to commission splits, percentages, etc. may violate a few rules, regulations and even law so...........Good luck in your switch. Always remember that the grass is not always greener someplace else. It stays green where YOU are taking care of it.