The more sellers you have on a listing in the Amazon Marketplace, the less control a brand will have when it comes to advertising, promotions, content, customer service and pricing. It's important to understand how the number of sellers directly impacts your brands equity. Many people make the mistake of thinking that an increase in sellers means an increase in sales for them. This couldn't be further from the truth and i'll explain why.
Let's say a products volume is 500 units a month and has 10 sellers on the listing. Each seller will have their share of selling 50 units a month. The problem with having so many sellers is that all it takes is for one of these sellers to go rogue and decide that they want more shares so they drop their price, causing the rest of the sellers to do the same to stay competitive. In many cases, this continues to happen until all of the margin is squeezed out, forcing sellers to stop selling the product due to little or no profit.