Original Research · 859 Possessory-Interest Parcels · 8 Colorado Counties
Two Hangars, Two Tax Bills: Colorado’s Possessory-Interest Fork
Build a hangar on leased airport land in Jefferson County and the tax is capped at the value of your ground rent. Build the identical hangar one county over and you’re taxed on the full building, as if you owned it outright. A March 2026 appellate decision says two clauses in the lease decide which answer is legally right — and our compile of eight counties’ assessment rolls says most of the Front Range hasn’t read it yet.
By Charlie Young, Principal — former Managing Director at one of the nation's largest property tax firms · LinkedIn · July 2026
Private buildings on public land are everywhere once you look: hangars and FBO terminals on airport aprons, concession spaces in stadiums and terminals, travel plazas on toll-road land, operators on federal ski acreage. Colorado taxes the private party’s stake in these arrangements as a possessory interest — and the least-understood corner of Colorado property tax is what happens when the private party also built the building.
Get that question wrong and the swing isn’t rounding error. At one Boulder County airport, a single tenant’s hangar produces two parallel accounts — a possessory interest valued at $39,000 and a building schedule valued at $197,000. Eighty-three percent of that tenant’s assessed value depends entirely on which theory the county applies.
In March 2026, the Colorado Court of Appeals handed down Sheltair, the most direct answer yet to the ownership question. We then did what nobody appears to have done: pulled every possessory-interest parcel in eight Front Range counties — 859 parcels, $212 million in actual value — and cross-referenced them against improvement-only building schedules at the same government-land sites. The result is a county-by-county map of who follows which theory. It is not uniform. It is not close to uniform.
Methodology: SVA compile of county assessor and GIS records, July 2026 — every possessory-interest-classed parcel in Denver, Adams, Arapahoe, Douglas, Jefferson, Boulder, Larimer, and El Paso counties (n = 859; $212M actual value), cross-referenced against 627 improvement-only real-property schedules at the same government-land sites. Case law read from the slip opinions. All figures are public assessor record.
The doctrine in one paragraph
A private interest in tax-exempt government property is taxable when it looks enough like ownership: the Colorado Supreme Court’s Vail Associates test asks for independent revenue-generating capacity, exclusivity of use, and sufficient duration — and Cantina Grill clarified that exclusivity means exclusive as to your space; competitors elsewhere on the property don’t defeat it. Valuation is where possessory interests get generous: by statute, the value is the net present value of the contract rent through the stated initial lease term — renewal options ignored, common-area and service charges excluded. The tax is assessed to the holder personally, and unusually, no lien attaches to the property. Valued correctly, a possessory interest is usually a modest number: a discounted rent stream, not real estate.
The fork: two sentences in your lease
The fight starts when the tenant builds. Is the hangar the tenant’s own building on someone else’s land — taxed at full value like any other improvement — or just part of the leasehold, folded into the NPV-of-rent cap? Colorado’s answer comes down to title mechanics:
- Lease grants the tenant title during the term — even if the building eventually reverts without compensation: the tenant owns it, and full-value assessment is proper. That’s Rare Air (2019): title in the tax year controls, and the eventual reversion doesn’t change who owns it today. (One wrinkle the courts haven’t decided: in Rare Air the reversion ran to a private master lessee — whether title reverting straight to the government changes the analysis remains open.)
- Lease pays the tenant out for the building at the end: also ownership — Southard.
- Lease grants no title, the building attaches permanently, and the tenant walks away uncompensated: the tenant never owned it. Under Sheltair (Colo. App., March 19, 2026), the entire interest — land and building — is one unified possessory interest, capped at the NPV of the rents. The opinion is unpublished, so it persuades rather than binds, but its logic is careful and its two-part test is explicit: both no-title and no-compensation.
Who holds title during the term, and what happens at the end — the entire tax turns on those two clauses.
Same building, eight answers
Five counties run the full-value model as their default — including Arapahoe, where Rare Air itself arose, and where the biggest dollars sit. El Paso is the extreme case: the county publishes no possessory-interest classification at all, anywhere, so every airport tenant is simply carried as a commercial property owner. On the other side, the NPV-cap counties happen to include the state’s largest airport and Sheltair’s home county, where the assessor books the entire hangar-and-land interest as a single possessory value.
And then there’s Boulder, running both theories on the same tenants: a ground-lease possessory interest and a full-value building schedule, side by side, for one hangar. If that tenant’s lease is Sheltair-shaped — no title, no exit compensation — it is fair to ask why the second account exists at all.
Colorado prizes uniformity in taxation. One fact pattern producing five full-value counties, two NPV counties, and one county doing both is — at minimum — a sign that a lot of these assessments rest on methodology nobody has tested against the current case law. And methodology matters on its own: the Colorado Supreme Court has held that using the wrong valuation method by itself entitles the taxpayer to a corrected assessment, a point Sheltair itself relies on.
If you hold a ground lease on public land
- Pull the lease. Find the title clause and the reversion clause. No title during the term, permanent attachment, and an uncompensated walk-away — in a full-value county — means the county may be taxing you as the owner of a building the courts say you never owned.
- Count your accounts. A possessory-interest account and a building schedule at the same site is the double-assessment pattern. One of them deserves scrutiny.
- If your lease grants title during the term, you’re on the Rare Air side — full-value assessment is legally proper, and the play is ordinary valuation: is the building actually worth what the county says?
- The calendar is forgiving. Beyond the annual protest window, Colorado’s abatement process reaches back two tax years — and a methodology error is exactly the kind of defect it exists for.
The tenants this reaches aren’t only aviation: stadium concessionaires, toll-road plaza operators, terminal retailers, and any business that built where the ground under it belongs to the public. The lease has always mattered. As of March 2026, it may be the whole case.