There is a parent organization with one domain (high domain authority), and has two separate businesses (different products, market, customers..though slightly related), each with their own separate website.
I learned today that the client is thinking about combining everything on the main domain. I am not sure if it would be a sub-folder or sub-domain.
What are the possible negative impacts of combining three businesses on one domain, if organized appropriately? Wouldn`t it be better to keep them all separate since they are three separate businesses, but link to each other for a good user-experience?