Well all spam aside, lol. Given what you are wanting to do, it may depend slightly on where you live and exactly what you are going to do, this would be the route I would suggest to any of my clients.
#1 Start off your first company, which will later be your parent company as a sole proprietorship. Be sure to choose a name that will not conflict with any potential new companies that you will create. I often suggest choosing two letter or three letter Acronym which will allow you to name your other companies within those letters. Numbers work as well.
#2 When you honestly believe you are ready, willing, and able to start building under companies, it is time to change your main company into a corporation. I am assuming you are looking to do this to minimize liability, so I would suggest an open CEO seat. For many people their Ego wants to get in the way, but with a CEO seat up for nomination, you will build an extra layer of aminimity for yourself.
Now, if you utilized the anagram I talked about earlier, depending on a few factors, you won't need additional business licenses, checking accounts, admin staff, and many other cost factors at all. To give the example, My parent company is SIA. It is the parent company, a registered corporation out of Nevada (look up costs to determine what works best for you). I also have Set It Aside, SIA Professional Services, Select Information agency, Swap It All, etc. etc. etc. All of my little projects cost me next to nothing and I can use the same phone number and staff while starting off because my staff always answers the phone thank you for calling SIA.
This way, if any of your projects simply bomb or are not enough to be their own sustaining entity, you will not worry about developing individual identities for them and all the inherent costs. As each project does become self sufficient, you simply break the company away if you want and then you have an independent identity to it.
Hope this makes sense while I'm running a 104 fever.
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