Theoretically, lets say two people become a partnership. After becoming a partnership, their company makes $200,000 CAD and they incorporate after a couple months, and then make another $200,000 during the rest of the year.

How does the tax breakdown look? Is the first $200k taxed as "personal income" because it was done while they were a partnership, and the second $200k done as "business income" since it was earned while they were a business.

Or is the entire $400k taxed at the end of the year as business income because, at the time of the tax filing, they were a business and were therefore taxed as such, despite some of that income happening while they were still a partnership.

For context, me and my partner are starting a company and trying to plan out how we want to do this. This was a scenario we do not really know. We'll be seeing an accountant in two days in order to fully plan this, but accountants are expensive so I'd like to go in with enough knowledge as to not waste their time and get the most of it. Thanks for your time!