Form 3115 and Look-Back Cost Segregation: Claim Missed Depreciation

What Is Form 3115?

IRS Form 3115, Application for Change in Accounting Method, is the mechanism that allows property owners to retroactively apply cost segregation to a property that has been depreciated using the straight-line method in prior years. It is one of the most powerful and underutilized tools in real estate tax planning.

When you conduct a cost segregation study on a property you have owned for multiple years, Form 3115 allows you to claim all prior-year missed accelerated depreciation in a single tax year. This is called a Section 481(a) adjustment, and it does not require amending your previous tax returns. The entire catch-up amount is reported on your current-year return.

How the Look-Back Study Works

Here is a practical example. An investor purchased a rental property five years ago for $400,000 (with $320,000 in depreciable basis). For the past five years, the investor has been depreciating the property straight-line over 27.5 years, deducting approximately $11,636 per year.

In year six, the investor commissions a cost segregation study. The study identifies $96,000 in 5-year property, $16,000 in 7-year property, and $32,000 in 15-year property. If the study had been conducted in year one, the investor would have claimed significantly larger deductions in years one through five through accelerated MACRS depreciation and bonus depreciation on these components.

The Section 481(a) adjustment calculates the difference between what the investor actually deducted over the first five years (using straight-line on the entire building) and what the investor should have deducted (using accelerated depreciation on the reclassified components). This difference, which can amount to $50,000 to $100,000 or more depending on the property and the number of years, is claimed as a single deduction on the current-year tax return via Form 3115.

Advantages of the Look-Back Approach

The look-back study with Form 3115 offers several significant advantages. There is no need to amend prior-year returns, which saves time and complexity. The entire catch-up deduction is claimed in a single tax year, creating a large current-year benefit. The approach is explicitly sanctioned by the IRS through Revenue Procedure 2015-13 (as updated). And there is no statute of limitations issue because the change is implemented prospectively.

For investors who have owned properties for three, five, or even ten years without a cost segregation study, the look-back approach often produces the largest single-year tax benefit of any strategy available.

Filing Requirements

Form 3115 must be filed with your current-year tax return and a copy must be sent to the IRS National Office. Your CPA handles the filing, using the detailed asset classifications and depreciation calculations from your Stratum cost segregation report. The change in accounting method is filed under the automatic consent procedures, meaning IRS approval is not required before filing.

Stratum includes Form 3115 guidance and supporting calculations with every look-back study, ensuring your CPA has everything needed to file correctly.

Is a Look-Back Study Right for You?

If you own a rental property that you have been depreciating straight-line and have never had a cost segregation study, a look-back study is almost certainly worth pursuing. The longer you have owned the property, the larger the Section 481(a) adjustment will be, and the greater the current-year tax benefit.