There are a range of ways to consider it. In any format, it's likely that either provincial or federal governments would need to be collaborating with the provincial housing authority, which already assesses everyone's homes on an annual basis for the purpose of collecting property taxes. You would then be homing in on the high-value homes that meet your threshold—1%, 2%, 5% or 10%—and a potentially deferrable annual tax could be put on there in order to do two things. Remember, we have to ask, “What's the intention?”
First, the key intention has to be to slow down the growth of Canadian home prices, which are leaving earnings behind. If a pandemic-induced recession is unable to slow down home prices, we need to concede that—perhaps unintentionally, but nevertheless—our housing system is designed to tolerate home prices that leave earnings behind. We'd like to think about what policy mechanisms might help slow that down and signal, “Hey, right now we shelter high-value homes from taxation in a way that we don't shelter other kinds of assets.” That incentivizes people to treat that as a way to make a good return and not just to have an affordable home. How can we close that a little bit? That's a key first point.
Then, as a salutary benefit, it's going to collect some additional revenue, which we could then invest in building more purpose-built rentals, especially when it's green, co-op housing, etc.