Legal Question in Construction Law in California

It depends. If you have an individual license and are a sole proprietor, all you have to do is comply with the fictitious business name requirements and you can do business under as many names as you want, operate them separately, etc., because ultimately a sole proprietorship is just you. The separateness of your businesses is just a fiction as far as the law is concerned. Likewise a corporation, partnership, or LLC, again by complying with fictitious business name laws, can operate the same way, such as by setting up divisions, because it is considered one legal entity. What you cannot do is do business as a sole proprietor and be the responsible managing employee or officer for a business entity, and a business entity cannot operate legally separate businesses, such as a corporate subsidiary, on the same license.