There's a lot of discussion on here about whether cost segregation is worth it and what kinds of properties qualify. What I don't see talked about nearly as much is what happens after, like whether you can actually deploy those losses or whether they just sit in a carry-forward indefinitely.
The IRS classifies most rental activity as passive, which means a $200,000 depreciation loss from a cost seg study can only offset passive income unless you qualify for certain exceptions. Based on if you do qualify, that can determine how valuable the study actually is. STR operators with average stays of 7 days or less and material participation can reclassify rental activity as active, which means that cost seg deductions can reduce your regular income without needing REPS. And if you qualify as a real estate professional then your rental losses become active regardless of property type, making cost seg far more valuable for offsetting W-2 or business income.
Before spending on a study, it's worth understanding where you fit in. The study is the same either way but what you can do with the results is completely different depending on your tax situation.
Curious to hear where people here land. Are you using cost seg losses currently or debating whether the study makes sense in your situation?
Accountant · Los Angeles · Member since 2026 · 2 posts · 2 votes
2mo
You mentioned some great points. In addition, I'd like to add that where the owner/investor is located also plays a large role in whether a cost seg study is needed. For example, NY and CA are two states that don't conform to the federal tax treatment for bonus depreciation, hence, any accelerated deductions taken from a federal tax perspective can unintentionally trigger phantom income at the state level due to the addback. Tax providers should be careful in modeling out these scenarios specific to your client's situation.
Tax Accountant / Enrolled Agent · Houston, TX · Member since 2014 · 5k+ posts · 6k+ votes
2mo
"Before spending on a study, it's worth understanding where you fit in" - indeed, I'm kind of tired of repeating this on the forum, against the steady chorus of "cost segregation will save the world." :)
Accountant · Los Angeles · Member since 2026 · 2 posts · 2 votes
2mo
You mentioned some great points. In addition, I'd like to add that where the owner/investor is located also plays a large role in whether a cost seg study is needed. For example, NY and CA are two states that don't conform to the federal tax treatment for bonus depreciation, hence, any accelerated deductions taken from a federal tax perspective can unintentionally trigger phantom income at the state level due to the addback. Tax providers should be careful in modeling out these scenarios specific to your client's situation.
Accountant · Los Angeles, CA · Member since 2016 · 2k+ posts · 901 votes
2mo
You're hitting the part people skip over. Running a study and generating a big paper loss only matters if you can actually use it, and since the IRS treats most rental activity as passive, that loss usually just carries forward against passive income unless you fit an exception. The two common ways to unlock it: qualifying as a real estate professional and materially participating, which makes your rental losses nonpassive so they can offset W-2 or business income, or running a short-term rental where the average guest stay is seven days or less and you materially participate, which takes it out of the per-se rental bucket and can make the losses nonpassive without needing REPS. So the study itself is the same either way, but its real value depends entirely on which of those buckets you land in.
Dr · VA · Member since 2025 · 154 posts · 34 votes
2mo
Some clients receive wrong advise to do Cost SEg. In real situation, they even not qualify for the status and for many years, even didn't get rental losses due to high income earners.
CPA, CFP®, PFS · FL · Member since 2017 · 5k+ posts · 3k+ votes
2mo
Good breakdown, the STR loophole and REPS distinction is exactly the piece that gets skipped in most cost seg conversations. One thing to add on the passive side, even without STR status or REPS, a cost seg loss isn't dead money, it can still offset passive income from other rental properties in the portfolio, and if there's no other passive income to absorb it, it carries forward indefinitely and gets fully released the year that specific property is sold, so it's not lost, just deferred until an exit or portfolio-wide passive income shows up.
Also worth flagging on the STR side specifically, the average stay test applies at the property level and needs to be verified based on actual guest data, not listing terms, and material participation still needs to clear one of the actual IRS hour tests, self-managing alone doesn't automatically qualify someone. On REPS, the 750-hour and more-than-half test applies per taxpayer, not per property, so a couple filing jointly where only one spouse qualifies still gets the benefit if that spouse's hours clear the bar and rental activities are properly grouped.
There's a lot of discussion on here about whether cost segregation is worth it and what kinds of properties qualify. What I don't see talked about nearly as much is what happens after, like whether you can actually deploy those losses or whether they just sit in a carry-forward indefinitely.
The IRS classifies most rental activity as passive, which means a $200,000 depreciation loss from a cost seg study can only offset passive income unless you qualify for certain exceptions. Based on if you do qualify, that can determine how valuable the study actually is. STR operators with average stays of 7 days or less and material participation can reclassify rental activity as active, which means that cost seg deductions can reduce your regular income without needing REPS. And if you qualify as a real estate professional then your rental losses become active regardless of property type, making cost seg far more valuable for offsetting W-2 or business income.
Before spending on a study, it's worth understanding where you fit in. The study is the same either way but what you can do with the results is completely different depending on your tax situation.
Curious to hear where people here land. Are you using cost seg losses currently or debating whether the study makes sense in your situation?
Great thread, and @Ashish Acharya point about the losses not being "dead money" is worth repeating. I see people give up on cost seg the second they hear the word "passive," when really it just sits and waits for the right trigger.
One thing nobody's touched on yet: what happens on the back end when you eventually sell a property you cost-segged hard.
If the exit plan involves rolling into another property, most people assume a straight 1031 covers everything. It doesn't fully solve the recapture problem. Accelerated depreciation gets recaptured differently than the deferred gain, and that unrecaptured 1250 piece follows you into the replacement property's basis math.
Where it gets interesting is build-to-suit (improvement) exchanges. Instead of just buying an existing replacement property, you can have a qualified intermediary or exchange accommodation titleholder hold title while construction or improvements happen, and those costs count toward your exchange requirement. Done right, that lets you "reload" a fresh cost seg opportunity on the new build inside the same exchange.
The catch, and this is where I've seen deals go sideways: you still only get 180 days total, and that clock doesn't pause for permitting delays or a contractor falling behind. If the work isn't done and title hasn't transferred back by day 180, the exchange can blow up entirely. It also adds another party holding legal title, which tends to make lenders nervous and financing more complicated than a plain-vanilla exchange.
@Rohullah Sharifi comment is the flip side of this too. Plenty of these strategies (STR loophole, REPS, build-to-suit) get recommended without anyone checking if the person actually clears the hour tests or timelines required. The strategy on paper and the strategy that survives an audit aren't always the same thing.
So like @Aaron Weikle said originally, the study is the easy part. Whether it's REPS, the STR angle @Jason Malabute laid out, or a future exchange, the plan needs to exist before the cost seg check gets written, not after.
@Nitin Illiparambil, curious whether you've seen build-to-suit exchanges paired with cost seg on the state conformity side too, seems like it could compound the phantom income issue you mentioned if timing isn't tight.
Happy to Connect!
This post does not create a CPA-client relationship. The information contained in this post is not to be relied upon. Readers are advised to seek professional advice.
Real Estate Investor · Austin, TX · Member since 2017 · 85 posts · 19 votes
9h
One thing I'd add for the W-2 crowd: if you own multiple rentals, look at the grouping election under Reg 1.469-4 before the study. Treating your rentals as one activity lets losses from one property offset income from another. Skip the election and each property's losses sit in their own bucket until you sell that specific property.
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