There are two types of master accounts.
#1 – If you are using the same business license for each Baidu advertising account, it’s possible to create a master account to manage each of those easily. This would work if you are running several different Baidu advertising accounts for one large client. For example, if you had two or more different accounts for different units of Siemens.
#2 – If each Baidu advertising account uses its own business license, you will need to create at least ten accounts before being given access to a master account. Each account will have the same setup process and limitations as normal (minimum spend, business license, access to a Chinese phone to receive pin codes, etc), but you will have one convenient place to manage them all from.