Written for CPA firms and tax advisors. Property owners: the plain-language version is in our short-term rental cost segregation guide.
Clients rarely arrive asking about Section 469; they arrive having heard about "the STR loophole" and expecting their accountant to bless it. The mechanics are legitimate. The advisory work is verifying that this client, this property, and this tax year actually qualify, because the strategy fails at the facts, not at the law.
The classification mechanics
Under Reg. 1.469-1T(e)(3)(ii)(A), an activity where the average period of customer use is seven days or less is not a rental activity for Section 469 purposes. It is a trade or business, which means the per-se passive treatment of rentals does not apply and the general material participation tests of Reg. 1.469-5T govern instead. An STR owner who materially participates has non-passive income or loss; the loss offsets W-2 wages and business income. No real estate professional election is involved, which is exactly why the strategy is attractive to high-income clients with full-time jobs: REPS is out of reach, the STR tests are not.
Where cost segregation fits
Classification determines where a loss lands; cost segregation determines whether there is a loss worth landing. Straight-line depreciation on a residential structure rarely produces a meaningful net loss against STR income. A study reclassifies the short-life components (and furnished STRs are dense with 5-year property), bonus depreciation front-loads them, and for qualifying acquisitions after January 19, 2025, the full reclassified allocation generally lands in year one. The chain has three links: the study creates the deduction, bonus accelerates it, and the classification plus participation make it non-passive. Remove any link and the outcome changes character or size.
What to verify before the return is signed
- The average-stay computation. Seven days or less, computed across all customer use for the year, not eyeballed from the listing settings. A few 30-night winter bookings can drag a beach property over the line. Pull the actual booking data.
- Material participation, with evidence. One of the 1.469-5T tests must be met on facts that survive scrutiny, including the comparative element: if a co-host or manager logged more hours than the client, the 100-hour test fails regardless of the client's total. The tests and pitfalls are detailed in our material participation guide.
- Placed-in-service reality. The property must actually be in service as an STR in the deduction year: listed, available, and functioning as a rental, not still mid-renovation on December 31.
- The bonus rate. Acquisition date drives the rate (100% for qualifying post-January 19, 2025 acquisitions; phase-down rates before that). Verify contract and closing dates.
- Personal use. Section 280A allocation and vacation-home limits can complicate a property the client also uses; ask before assuming a pure rental.
What to hand the client
The strategy survives examination on contemporaneous records, and clients keep those records when their accountant tells them exactly what to keep. A one-page ask at engagement start: export of all bookings with stay lengths; a dated hours log with activity descriptions; management and co-host agreements; the closing statement; and dated photos of the furnished property. That list, plus a study with component-level documentation, is most of an examination response assembled in advance.
Long-term rental clients: same study, different landing
The study itself is not STR-specific. For long-term rentals the accelerated depreciation offsets passive income and builds carryforwards, and clients with real estate professional status reach ordinary income through Section 469(c)(7) instead, on substantially more demanding facts (750 hours and the more-than-half test). The advisory pattern is the same: size the deduction with the study, then let the client's Section 469 posture determine where it lands.
For firms with STR-heavy books: RentalWriteOff prepares residential and STR studies white-label under your brand or through a referral workflow. We support questions about the study and methodology; your firm handles participation, qualification, and filing advice. See the partner programs or more resources for tax professionals.