Material participation (IRC §469) is where most STR cost segregation strategies fail. A valid study doesn't help if the losses end up passive. This test tells you which bucket you're in — and what it's worth at your marginal bracket.
Under IRC §469, rental real estate losses are passive by default — they can only offset passive income, not W-2 or active income. But short-term rentals (average stay ≤ 7 days) are not treated as rentals for §469 purposes. That means the losses can be non-passive — IF the owner materially participates.
Material participation is defined by 7 tests in the Treasury regulations (Reg. §1.469-5T). You pass if you meet any one of them. For STR owners, the realistic tests are:
Tests 4 (significant participation across multiple activities) and 7 (facts and circumstances) are more involved and less commonly used for STR owners. If you think one of those applies to your situation, a CPA review is the right call.