The Canadian version runs the opposite way. Leaving California before a residency date avoided a tax. Ceasing Canadian residency triggers one: a deemed disposition of most property at fair market value on departure, so emigrating generally accelerates tax rather than avoiding it — and shares of a private corporation are among the assets caught.

The only generalisable part is the boring part: tax rules attach to measurement dates, so it is worth knowing which date a rule keys off before planning around it. Nothing else about this is a template for an Ontario-resident owner.