Basically, there are two things I will talk about. One is that the combination of lower tax rates, sales tax harmonization, etc., really incents businesses to grow. When they grow they create jobs, they create value, they earn money. They are more incented to have their head offices here in Canada as opposed to outside Canada, so there's that incentive.
Also, when you get into the technical areas of tax planning, you hear a lot about transfer pricing in the sense that there are various fees charged around the world to perhaps shift profits from country A to country B. If you're in a country with a very low tax rate, you tend to get more income coming in than expenses being charged to that area.