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IRS Form 3115 — Change in Accounting Method

Claim Years of Missed Depreciation
in a Single Tax Year

Already own your property? A lookback cost segregation study with Form 3115 lets you catch up on all the accelerated depreciation you've been missing — without amending prior returns.

Calculate Your Catch-Up →

What Is a Lookback Study?

Recover missed depreciation from every year you've owned your property.

When you purchase a property and don't perform a cost segregation study at that time, you miss out on accelerated depreciation every single year. A lookback study retroactively identifies the components that should have been depreciated on shorter schedules.

By filing IRS Form 3115 (Application for Change in Accounting Method), you can claim all the cumulative missed depreciation as a single catch-up deduction in the current tax year. No amended returns. No multi-year filings. One form, one deduction.

How It Works

1
We perform a cost segregation study as if it were done at purchase
2
We calculate the cumulative missed accelerated depreciation
3
Your CPA files Form 3115 and claims the full catch-up in one year

Who Qualifies for a Lookback Study?

If any of these apply, you're likely leaving money on the table.

Bought Without Cost Seg

You purchased your property and never had a cost segregation study performed.

Owned 2+ Years

The longer you've owned the property, the larger the catch-up deduction.

Residential Property

Single-family rentals, STRs, duplexes, condos, and multifamily buildings.

Commercial Property

Office, retail, industrial, restaurant, medical office, and mixed-use buildings.

No Prior Amended Returns

Form 3115 is filed with your current-year return — no amendments needed.

Property Still in Service

The property must still be actively used and not yet sold or disposed of.

How Much Could You Catch Up?

Estimated Catch-Up Depreciation
$0
Order Your Lookback Study →

Get your lookback estimate by email + learn how Form 3115 works

Real Example: $500K Rental Purchased in 2019

Property3BR/2BA SFR
Purchase Price$500,000
Year Purchased2019
Years Owned7
Study TierResidential ($895)

This investor never performed a cost segregation study at purchase. By doing a lookback study and filing Form 3115, they claimed over $42,000 in cumulative missed accelerated depreciation — all in a single tax year.

Total Catch-Up Depreciation
$42,000
claimed in a single tax year via Form 3115
$15,540
Tax Impact (37%)
17x
ROI on Study Cost
7
Years Recovered
3115
Method: Form 3115

Lookback Study Pricing

Lookback studies are priced the same as standard cost segregation studies. We perform the full analysis and calculate your catch-up amount. Your CPA handles the Form 3115 filing.

Residential
$895
$1,095 for properties $1M+
Commercial
$1,495
$2,995 for properties $5M+

Frequently Asked Questions

Form 3115 is the IRS Application for Change in Accounting Method. When applied to depreciation, it allows you to change from straight-line depreciation to accelerated depreciation schedules identified by a cost segregation study. The key benefit: all the cumulative missed depreciation is claimed as a single catch-up deduction in the current tax year.
No. That's the power of Form 3115 — the entire catch-up adjustment is taken in the current tax year. You do not need to file amended returns for any prior years. Your CPA simply files Form 3115 with your current-year tax return.
There is no time limit. The longer you've owned the property without a cost segregation study, the larger the cumulative catch-up deduction. Whether you purchased 3 years ago or 15 years ago, a lookback study can recover all the missed accelerated depreciation.
The study accounts for any prior accelerated depreciation already claimed. The catch-up deduction is calculated as the difference between what you should have depreciated under the accelerated method versus what you actually claimed under straight-line depreciation.
Your CPA files Form 3115 with your current-year tax return. We provide the complete cost segregation study with all the data your CPA needs — including the cumulative catch-up amount, component schedules, and supporting documentation. Your CPA handles the actual filing.
Yes. Any remaining bonus-eligible components in the current year get bonus depreciation treatment on top of the catch-up. This means you can claim the cumulative missed depreciation from prior years plus current-year bonus depreciation on eligible assets — maximizing your total deduction.

Every Year You Wait Is Another Year of Missed Deductions

File a lookback study and claim years of missed accelerated depreciation — all in a single tax year. Studies start at $895.