IMO, "new business" is defined differently, depending upon the branch of government you are interested in presenting your "new business" to.

It it's to immigration. The IND clearly defines what a new business is, and that is extremely easy to not only find, but to comrehend.

It your purpose is without regard to immigration, and strictly with regard to Taxation, then there is a Ministry of Taxation, and that would be a good place to begin to research the definition of a new business.

On the other hand, I know of no business that does it's own accounting, and you obviously have an Accountant.

An accountant or what we call a Certified Public Accoountant in the US, whom prepares individual and commercial taxes, would definitely know what quailifies as a new business
for the purpose of Taxation, and that would be faster, easier, and if your accountant is not a complete idiot, would certainly know what would qualify as a new business in the eyes of the Ministry of Taxation.

However, there are surely other laws and departments, such as those that control Labor, and Business Registration on a (local and national level) which also come into play, and would have their own set of rules for you to be aware of. AGAIN... an accountant or better yet, an Attorney whom establishes new businesses, and handles such things as an exchange of ownership would be an even more reliable and knowledgable source of information.

Soz, but I don't think your question can rightly be correctly answered in a SINGLE way, NOR are your PRIORITIES entirely clear, as to these issues.

The IND is easy enough for you to locate, read, and understand, enough about a new business. Keep in mind any restrictions that might apply to you, given what ever origin you are.

(Why doesn't anyone EVER sayu what the hell Country they are a Citizen of???
It's such damn common knowledge that EEU rules, Dutch Treaty obligations and rules and exemptions established
from the Treaties, and NON-treaty Nations ALL are treated differently with regard to business establishment, and change of business/purpose of stay, as per VUSA's. I can't begin to guess why anyone AS A RULE ALLWAYS NEVER specifies their Country of Origin and Citizenship, except to get a bunch of speculation in response.)