What is the federal Underused Housing Tax and does it apply if I own my home through a corporation?

The Underused Housing Tax is a federal, annual tax created under the Underused Housing Tax Act, aimed generally at residential property in Canada that is considered vacant or underused, with its main practical target being non-resident, non-Canadian owners. It is entirely separate from any municipal vacant home tax a city like Toronto or Ottawa might charge on the same property, discussed further in a related question - the two are different levies from different levels of government.

Owning your home through a corporation, even a Canadian one, is exactly the kind of structure that can pull you into this tax's filing rules, because the automatic exclusion available to individual Canadian citizens and permanent residents who own property directly and personally generally does not extend the same way to a corporation. A Canadian-owned corporation may ultimately qualify for an exemption from actually paying the tax, but that typically still requires filing a return to claim it, rather than the obligation disappearing on its own.

Because filing penalties can apply even where no tax is ultimately owed, confirm your corporation's specific filing obligation with a tax advisor rather than assuming Canadian ownership alone resolves the question.