How are employee stock options from my private Ontario corporation taxed when I exercise them?

Generally, no tax is triggered when your employer grants you stock options, the taxable event comes later, when you actually exercise them, at which point the difference between the shares' fair market value at exercise and what you paid to acquire them under the option is treated as employment benefit income. For options from a genuine Canadian-controlled private corporation, though, there's a meaningful timing advantage built into the Income Tax Act: rather than being taxed right at exercise, the benefit is generally deferred until you actually sell or otherwise dispose of the shares.

This deferral matters in practice because exercising a private-company option doesn't put cash in your pocket the way selling shares does, without the CCPC deferral, you could owe tax on paper income before you have any way to fund it from a real sale. By pushing the tax point to the eventual disposition, the CCPC rules line up the tax bill with the point where you actually have proceeds to pay it from.

Because this favourable timing depends specifically on the company genuinely being a CCPC at the relevant times, and can change if the company's status changes, understanding your specific company's status is important to knowing which timing rules actually apply to your options.