How do you create a sister company?

Answer 1

A sister company generally means a company that has the same corporate parent as another. For example, if Corporation A and Corporation B are both subsidiaries of Corporation XYZ, Corporation A and Corporation B are sister companies. I have occasionally seen two companies which are owned by the same individual referred to as sister companies since they have the same ownership (just like in the parent-sub example) but that usage is less common. In that case, there is no "parent" company.

If you have only one company and want a sister company in the classic sense, you need to first set up a holding company to own the shares of the first company and then set up a new subsidiary under the holding company.