Put an exponent in the property tax calculation based on number of properties owned (by individual or business) within a jurisdiction.

ex. taxes are [rate * appraisedValue * 1.1 ^ numPropertiesOwned]

Needs some sort of mechanism to prevent corporations from spinning up subsidiaries to use as a tax shield in these calculations though.

This is how Singapore addressed the housing crisis and I think it would be a great idea for Canada to follow suit. It levels the playing field between the 30 year old couple looking to start a family and massive REITs/corporations with billions in capital.

Because lots of government make a lot of money and have multiple homes.

It's a fine black of pretending to do something, but just not enough to hurt your friends.

Property tax is on the property, not on the owner. The municipality doesn't know and can't know who actually pays the taxes on a property. To have each municipality create their own spy agency to determine who is making the e-transfer for each roll number on their list will cause more problems than it solves.

Rental properties are also in extremely low supply. I'm not confident we should see corporations owning housing as a bad thing, given they can get rental housing built in bulk. Plus every new rental that's built will also indirectly put downward pressure on prices as well.