If a previous accountant never depreciated a piece of property, or got it wrong for more than a year, the fix is not three amended returns and three years of penalty exposure. There's a single IRS form that lets you catch up everything you missed, however many years back, as one deduction on this year's return.
The instinct when you discover a previous preparer never depreciated a rental property, a piece of equipment, or a building improvement is to amend the return and fix it. That works, but only for one year. The moment depreciation was missed or miscalculated for two or more consecutive years, the IRS stops treating it as a simple mistake and starts treating it as an accounting method, and a method has to be corrected through a formal change, not an amendment.
That change is requested on Form 3115, Application for Change in Accounting Method. It sounds like more paperwork than an amended return, but it actually does something an amended return can't.
The mechanism that makes Form 3115 valuable is Section 481(a) of the tax code. It calculates the full, cumulative difference between the depreciation that was actually claimed and the depreciation that should have been claimed, then lets you take that entire difference as one deduction, in the current year, on the return you're filing right now.
Here's the detail most people don't expect: an amended return can generally only reach back three years. Form 3115 doesn't have that limit. Depreciation missed eight years ago on a rental property, or five years ago on equipment, can still be caught up in full, in one filing, this year.
When the missed depreciation results in a bigger deduction than what was claimed, and it almost always does, the adjustment is negative, and a negative 481(a) adjustment is deductible in full in the year of the change. Not spread over several years. All of it, at once.
Say a Frederick County landlord bought a rental property years ago and a previous preparer depreciated it correctly for the first two years, then simply stopped including it on the depreciation schedule, an oversight that went unnoticed for the next five years. Across those five years, roughly $60,000 in depreciation should have been claimed and wasn't. (If passive activity rules are also part of the picture for this same property, that's a separate wrinkle worth understanding, we cover it in why your rental property losses might be "stuck".)
| Amending Prior Returns | Form 3115 with a 481(a) Adjustment | |
|---|---|---|
| How far back you can reach | Generally 3 years only | No set limit, the full history of missed depreciation |
| Missed depreciation recovered | Only whatever falls in the 3-year window | The entire $60,000, regardless of when it was missed |
| Paperwork | A separate amended return for each year | One form, filed with this year's return |
| IRS approval needed | Each amendment reviewed individually | Automatic consent, no waiting, no user fee |
Amending would only recover whatever fell in the last three years, a fraction of what was actually missed. Filing Form 3115 recovers the entire $60,000 as a single deduction on this year's return.
Most of what's written about Form 3115 focuses on real estate investors catching up depreciation after a cost segregation study, and that's a real, common use. But the same mechanism applies just as directly to an ordinary small business owner whose previous accountant simply never added a piece of equipment to the depreciation schedule, misclassified a building improvement, or used the wrong recovery period for years without anyone catching it. This is exactly the kind of thing clean, actively managed bookkeeping is supposed to catch early. If you switched preparers and the new one noticed something the old one missed, this is very likely the tool for fixing it, not an amended return.
Correcting a depreciation method qualifies as an automatic change under Designated Change Number 7, governed by Rev. Proc. 2015-13 and the IRS's current annual list of automatic accounting method changes. "Automatic" means exactly what it sounds like, no advance IRS approval required, no user fee, the form is simply prepared correctly and filed alongside the return for the year of the change. A duplicate copy also gets mailed separately to the IRS's Ogden, Utah service center, a procedural step that's easy to miss and worth double-checking before anything's considered filed.
One nuance worth knowing on the other side of this: if a mistake went the opposite direction and depreciation was overclaimed, there's a de minimis rule allowing adjustments under $50,000 to also be resolved entirely in the year of change, rather than a more complicated multi-year spread.
Send us your depreciation schedule and we'll tell you honestly whether Form 3115 applies, what it would recover, and what it would cost to fix. Call (301) 662-6992.
Book a ConsultationThere's no set lookback limit the way there is with amended returns, which are generally restricted to three years. A 481(a) adjustment captures the full cumulative difference between what was claimed and what should have been claimed, regardless of how many years ago the depreciation was missed.
No. That's the entire point of filing Form 3115 instead. The catch-up amount is taken as a single deduction on the current year's return, and prior returns are left untouched.
No. It's commonly used alongside cost segregation studies, but the same mechanism applies to any missed or miscalculated depreciation on business property, equipment, vehicles, or building improvements, whenever the error carried on for more than one year.
Filing a properly prepared Form 3115 under an automatic change procedure is a routine, IRS-sanctioned process, not something that inherently raises red flags. The key is accurate documentation supporting the 481(a) calculation, which is exactly what a defensible filing is built to provide.
By Roy Cogliandolo, CPA · Mercer Flanagan · August 30, 2026
This article is general information, not tax advice for your specific situation. Rules cited reflect current IRS procedures as of August 30, 2026, and are complex enough that professional review is strongly recommended before filing.