Who has to file an Underused Housing Tax return even if they don't actually owe any tax?

The Underused Housing Tax works through a category the rules call an "affected owner," and being in that category can require you to file a return even where an available exemption means no tax is ultimately owed. This generally includes owners who are not Canadian citizens or permanent residents, along with certain Canadian entities - private corporations, trustees of a trust, and partners in a partnership that owns residential property - who do not automatically qualify for the exclusion available to individuals holding title directly and personally as Canadian citizens or permanent residents.

The reason filing still matters even when an exemption exists is that several exemptions have to be actively claimed on a return rather than applying automatically, so simply believing you qualify is not the same as having filed to establish it. Missing the filing can mean losing the practical benefit of an exemption you were otherwise entitled to, on top of the penalties covered in a related question.

If your ownership involves a corporation, trust, or partnership, or you are not a Canadian citizen or permanent resident, confirm your filing obligation directly rather than assuming an exemption means no return is needed.