Currently going through court is the case against the foreign buyers tax (which could likely be applied to the speculation tax).
Looking at the legality I think they will win on that it violates several of our international treaties and the charter challenge (not arguing here if the tax is good or not but they make several good points why its illegal). Barry Appleton who is a highly respected NAFTA lawyer gave a good explanation of why it violated NAFTA here
https://www.straight.com/news/746041/tra...ax-foreign-buyers-housing-violates-nafta
Lawyers update on the trial is here
http://www.branchmacmaster.com/foreign-nationals-property-tax/
Amended notice of claim is here
http://static1.1.sqspcdn.com/static/f/29...ken=nDMtAK1QJCTFIGAn%2B4%2BYdp%2F15xE%3D
A reminder that this post is based on discussing the legality rather than the merits.