The first-class company refers to the parent company or holding company, which holds the shares or control rights of other companies and is the starting point of the control chain. A secondary company refers to a company controlled by a primary company, which usually does not hold shares or control rights of other companies, but acts as a subsidiary or branch of a primary company.
In the relationship between equity and control, the first-level company is the starting point and actual controller of the equity chain, and the second-level company is the extension of the equity chain.