The IRS has a "sort-of" definitive answer about when a business begins, but it waffles a little too. In this article, it discusses the corporation as a specific business entity:
"Ordinarily, a corporation begins business when it starts the business operations for which it was organized... on the date of its incorporation. Mere organizational activities, such as the obtaining of the corporate charter, are not alone sufficient to show the beginning of business." <a rel="nofollow" target="_blank" href="
https://www.irs.gov/irb/2008-34_IRB">https://www.irs.gov/irb/2008-34_IRB</a>
But the IRS also says that "activities of the corporation," for example, buying necessary operating assets, might be a sign that the business has begun.
The concept of going concern comes into play to determine when a business starts. A going concern has an active customer base, is working on advertising, marketing, and other means to gain more customers, and is taking in money from sales. A going concern does not need to be making a profit, but only to show the intent to operate so as to make a profit.
You could say a business starts when it becomes a going concern; that is when it begins operating independently with the purpose of making a profit, with business records being kept, and customers being solicited.
Hope this helps.
