STR Owner Captures $187K Catch-Up Depreciation via Form 3115

The Problem

This client had purchased a $640,000 mountain cabin in western North Carolina four years earlier and had been operating it as a short-term rental generating $92,000 in annual gross rental income. The prior CPA had been depreciating the property on a standard 39-year straight-line schedule, claiming approximately $13,900 per year in depreciation. Over four years, the client had claimed $55,600 in total depreciation — a fraction of what was available through cost segregation.

The client assumed that cost segregation was only beneficial at the time of purchase and that the window for accelerated depreciation had closed. This is one of the most common misconceptions in real estate tax planning. Under the IRS's accounting method change procedures outlined in Rev. Proc. 2015-13 and Section 481(a) of the Internal Revenue Code, taxpayers who previously depreciated assets under an incorrect method (or a less favorable permissible method) can file Form 3115 to change to the correct method and capture all missed depreciation in a single §481(a) adjustment in the year of change.

AE Tax Strategy

1. Cost Segregation Study on Existing Property Under IRC §168

We commissioned a cost segregation study on the property, which identified $224,000 (35% of the depreciable basis) in components eligible for reclassification: $108,000 in 5-year property, $52,000 in 7-year property, and $64,000 in 15-year property. Under the bonus depreciation rules in effect at the time of original placement in service, these components were eligible for 100% first-year expensing. The study was conducted to engineering-based standards using the detailed engineering approach recommended by the IRS Cost Segregation Audit Techniques Guide.

2. Form 3115 Accounting Method Change Under IRC §481(a)

We filed Form 3115 (Application for Change in Accounting Method) using the automatic change procedures under Rev. Proc. 2015-13 (as modified by subsequent revenue procedures). The change was filed under DCN 7 (change in depreciation method, recovery period, or convention for depreciable property). The §481(a) adjustment calculated the difference between depreciation actually claimed over four years ($55,600) and depreciation that would have been claimed had cost segregation been performed at acquisition ($242,600 in Year 1 plus normal depreciation in Years 2-4). The net favorable §481(a) adjustment was $187,000, deductible in full in the year of change.

3. Material Participation and Loss Utilization

Because the property was a short-term rental with average stays of 4.2 days, it qualified for the non-rental activity exception under Treas. Reg. §1.469-1T(e)(3)(ii). The client, who personally managed bookings, guest communications, cleaning coordination, and maintenance, logged 380 hours of direct involvement — well above the 100-hour safe harbor threshold. This allowed the $187,000 catch-up depreciation deduction plus current-year depreciation to create a non-passive loss that offset the client's $340,000 W-2 income. At the combined 32% federal plus 4.75% North Carolina marginal rate, the $187,000 deduction produced approximately $68,700 in tax savings.

Before & After Comparison

Tax Category	Before	After	Savings
Prior Depreciation (4 Years Total)	$55,600	$55,600	$0
Section 481(a) Catch-Up Adjustment	$0	$187,000	$187,000
Tax Savings at 36.75% Rate	$0	$68,700	$68,700
Total	$55,600	$242,600	$187,000 (catch-up deduction)

Key Takeaways

• Cost segregation is not limited to newly purchased properties — Form 3115 allows catch-up of all missed accelerated depreciation in a single tax year, regardless of how long the property has been owned.
• The Section 481(a) adjustment is a one-time, lump-sum deduction that does not require amending prior returns — the entire benefit flows through the current year's return.
• Form 3115 filed under the automatic change procedures does not require IRS approval — the taxpayer simply attaches the form to the return and files a copy with the IRS national office.
• The combination of Form 3115 catch-up depreciation with STR non-rental classification and material participation creates one of the most powerful single-year tax reduction events available.