Cost Segregation On Mid-Year Conversions

By Jason Watson, CPA
Posted Sunday, March, 22, 2026

Let’s talk about mid-year conversions. What happens if you run a short-term rental (STR) for the first four months of the year, convert it to a long-term rental (LTR) for the remaining eight months, successfully treat them as two separate economic units on your tax return under Treasury Regulations Section 1.469-4(c), and then decide to do a cost segregation study?

Do you take the massive bonus depreciation deduction and slice it up by allocating 4/12ths to the STR and 8/12ths to the LTR?

No. You do not. And understanding exactly why is the difference between a massive tax refund and a massive tax trap. Oh, let’s not forget an incorrect tax return as well.

The Point-in-Time Rule

Bonus depreciation is not a monthly, prorated concept. It is a point-in-time deduction. It drops like an anvil the exact moment the property (or its cost-segregated components) is first placed in service for a business use.

Standard MACRS depreciation is prorated based on the applicable depreciation conventions and the portion of the year each activity operated, but bonus depreciation is claimed in full by whatever activity is happening on day one. Because of this, the order in which you operate the property dictates exactly which bucket that giant tax loss lands in.

STR First, Then LTR (The Winner)

Let’s say you place the rental property in service as an STR in January. You materially participate, manage the guests, and satisfy the 7-day rule. Do all the right things.

In May, you get tired of the turnover, or perhaps ski season is closing out, and lease it to a long-term tenant. Because it was an STR when it was first placed in service, the STR activity claims the entirety of the bonus depreciation. Assuming you materially participated, this creates a massive non-passive loss that can offset your W-2 or business income.

When the property converts to an LTR in May, it inherits the remaining, much lower adjusted basis. The LTR activity simply claims the standard, prorated MACRS depreciation on the leftovers for the remaining eight months.

Mechanically, there are a couple of things to keep in mind. First, you will list two activities on your tax return- one for the STR version and another for LTR version of the same actual real estate asset. Next, you will have two depreciation schedules as well, and the LTR’s unadjusted cost basis will be the STR’s original cost basis less whatever depreciation including bonus depreciation was deducted on that activity.

LTR First, Then STR (The Trap)

Now, let’s flip it. You place the property in service as an LTR in January. In May, the tenant moves out, and you decide to turn it into an Airbnb to hit the juicy summer travel traffic. You do a cost segregation study since now it qualifies as an STR and can deduct against your big W-2 income.

Because it was an LTR when it was first placed in service, the LTR activity claims the bonus depreciation. Unless you are a qualifying Real Estate Professional (REPS) or have other passive income, that massive cost segregation and subsequent depreciation loss drops straight into your passive bucket and gets trapped. Yuck.

When you convert to an STR in May, you might materially participate and run a great hospitality business, but the depreciation damage is done. Just like our other example, the STR activity only inherits the remaining adjusted basis and gets a tiny sliver of standard MACRS depreciation. The giant STR loss bomb you were hoping to trigger was already detonated in the passive bucket. Ok, that was a bit over the top, but whatever.

The Takeaway

If you are treating a mid-year conversion as two separate activities, there is no magic rule that lets you assign the bonus depreciation to the activity you prefer. It is strictly dictated by the placed-in-service date.

If your strategic intent is to use the STR loophole to offset ordinary income, the property must be placed in service as an STR first. Flipping an LTR to an STR mid-year mechanically works the same way, but strategically, it traps your best tax deductions behind the passive loss wall. Timing isn’t just everything; it is the only thing.

The Reboot Myth And The Entity Shuffle

Some clever real estate investor is inevitably going to ask: “Wait, if an STR is a totally different business than an LTR, why can’t I just take the LTR out of service, and then ‘re-place’ it into service a week later as a brand-new STR to grab the bonus depreciation again? Or better yet, what if I sell it to a new multi-member LLC I own with my spouse so a ‘new taxpayer’ buys it?”

Nice try, but the IRS saw you coming a mile away. You cannot unplug your rental property and plug it in somewhere else and reboot your tax deductions. Here is why the tax code crushes both of these maneuvers:

Under IRC Section 168(k), bonus depreciation is strictly a “first placed in service” deduction. The IRS only cares about the very first time you made that specific asset ready for any income-producing activity. Transitioning from an LTR to an STR is classified as a “Change in Use” under Treasury Regulation Section 1.168(i)-4. It may change how the property is classified for depreciation purposes, but it does not reset the original placed-in-service date.

Sidebar: The one exception? Brand-new assets you buy specifically for the STR, like a hot tub or new furniture. Those get their own fresh placed-in-service date and their own bonus depreciation. Yeah, this doesn’t make you feel any better.

If you try to outsmart the system by dropping the property into a new LLC with your spouse or your S Corp, you hit two brick walls:

• If you simply contribute the property to the new LLC, the entity “steps into your shoes” as suggested by IRC Section 168(i)(7). It inherits your exact depreciation schedule, remaining basis, and original placed-in-service date.
• If you actually sell the property to the LLC to claim bonus depreciation on “new to the LLC” property, you trigger related party transaction rules. Because you, your spouse, or your controlled entities own more than 50% of the new entity, the IRS disallows the bonus depreciation entirely, and you just triggered a taxable sale for absolutely no reason.

Here is the exact language of IRC Section 168(i)(7) which will completely put you to sleep:

(7) Treatment of certain transferees
(A) In general
In the case of any property transferred in a transaction described in subparagraph (B), the transferee shall be treated as the transferor for purposes of computing the depreciation deduction determined under this section with respect to so much of the basis in the hands of the transferee as does not exceed the adjusted basis in the hands of the transferor.

The house always wins. The asset keeps its original history, and the bonus depreciation clock does not reset.