Cost Segregation for Apartment Syndications: How It Works in 2026

Cost segregation is a tax study that splits an apartment building's cost into parts that depreciate faster, such as appliances, carpet and parking lots, instead of writing everything off over 27.5 years. In a syndication, whether investors can use the resulting losses depends on passive activity rules, and some benefit returns as recapture on sale.

If you are the sponsor, we built DoorRaise to handle the K-1s and tax reporting that follow a study, while your CPA decides whether to order one.

This guide sits inside our complete guide to real estate syndication. It stays on one question: how does a cost segregation study work in an apartment syndication? For the wider tax picture, see apartment syndication taxes for beginners.

What is cost segregation?

Cost segregation is an allocation exercise. A study takes the total cost of a property and assigns pieces of it to different asset classes with different recovery periods. The IRS describes it in its Cost Segregation Audit Techniques Guide (Publication 5653) as involving "the allocation (or reallocation) of the total cost (or value) of property" among property classes and recovery periods.

For a building you buy, cost records usually are not available. The guide says the detailed engineering approach from actual cost records "is generally applicable only to new construction," and that a detailed estimate approach is "used when cost records are not available." The same guide notes that "there are no prescribed qualifications for cost segregation preparers," so ask for credentials and sample work.

Which parts of an apartment building qualify?

Most of the building stays on the 27.5-year schedule, while some components can move to shorter schedules. Under 26 U.S.C. 168, residential rental property has a 27.5-year recovery period, and a building qualifies when at least 80% of its gross rental income comes from dwelling units. The categories below are typical, but your study decides the real allocation.

Pub 5653 gives 5 and 7 years as examples of the shorter recovery periods for tangible personal property. The 15-year class for land improvements is common practice, so confirm the classification with your CPA and study preparer. IRS Publication 946 is the main reference for recovery periods and the special depreciation allowance.

How does bonus depreciation work in 2026?

Bonus depreciation lets you deduct a large share of qualified property's cost in the first year instead of spreading it out. Publication 946 says Public Law 119-21 reinstated a 100% allowance for certain qualified property acquired and placed in service after January 19, 2025. Publication 946 also states that a 40% allowance applies to certain property acquired after September 27, 2017 and placed in service in 2025, with an election available in some cases.

Two details matter for sponsors:

1. The contract date. In Notice 2026-11, the IRS states that "property is not treated as acquired after the date a written binding contract is entered into for such acquisition." If your purchase contract was signed on or before January 19, 2025, the shorter-life parts do not get the 100% rate. Under the earlier phase-down schedule, the percentage was 40% for property placed in service in 2025. Look at the date, not the closing.
2. Elections. The IRS news release on the notice describes an election to take 40% instead of 100% for property placed in service in the first tax year ending after January 19, 2025. Your CPA may use elections to manage taxable income.

Bonus depreciation does not apply to the building itself, which stays on the 27.5-year schedule. Some states do not follow the federal rules, so ask how yours treats it. See the IRS news release on Notice 2026-11. The notice is described as interim guidance, with proposed regulations expected, so confirm current rules before you close.

A worked example

This example is illustrative only, with round numbers, and assumes the property qualifies for 100% bonus depreciation. We computed every figure in Python.

The 25% is an assumption for illustration. Real allocations vary by property, and we cannot tell you a typical percentage. First-year straight-line amounts are lower in practice because of the mid-month convention, so treat the straight-line rows as full-year figures.

What it means for one investor

Now follow a hypothetical investor who owns 2% of the LLC and is allocated income and loss pro rata.

The point of the example is timing. The deduction can arrive early and recapture can arrive on sale. The extra deduction could be worth less than shown if the investor cannot use the loss that year, and the recapture amount depends on the sale price and the property type.

Also, partnership allocations follow the operating agreement and the tax rules, so a pro rata share is a simplification. See syndication operating agreements.

Can investors actually use the losses?

Often not right away. Under 26 U.S.C. 469, a rental activity is a passive activity, and passive losses are generally disallowed against other kinds of income. They can offset passive income, such as income from other rentals or syndications. Unused losses carry forward and are released in a fully taxable disposition of your entire interest, with special rules.

Four limits matter:

• The $25,000 allowance. Section 469(i) lets some individuals deduct up to $25,000 of rental loss if they actively participate. The allowance phases out by 50% of the amount that adjusted gross income exceeds $100,000, reaching zero at $150,000. An interest of less than 10% by value is not treated as active participation, and a limited partner interest in a limited partnership is not treated as actively participating, except as regulations provide.
• Real estate professional status. There are separate tests for people who work heavily in real estate. Material participation is a facts-and-hours question for your CPA.
• Excess business loss. If a loss gets past the passive rules, another cap applies. For 2026, IRS Rev. Proc. 2025-32 sets the excess business loss threshold at $256,000 ($512,000 for joint returns).
• Basis and at-risk limits. A loss is limited by the partner's tax basis and at-risk amount. The Schedule K-1 instructions describe the order of limits: basis, at-risk, passive, then excess business loss.

What happens when the property sells?

Some of the benefit is paid back. Under 26 U.S.C. 1245, gain on personal property is treated as ordinary income up to the depreciation previously taken. Land improvements and the building are handled under different rules, and the details depend on the property type, so ask your CPA to model it. The IRS says the portion of unrecaptured section 1250 gain "from selling section 1250 real property is taxed at a maximum 25% rate" (Topic 409).

A study can still help because deductions arrive years earlier, and money in hand sooner is worth something. But it is a timing benefit, not free money. A sponsor planning a quick sale may find the recapture arrives fast, while a long hold, or a 1031 exchange at the sponsor level, changes the picture. For the exchange side, see our guide to DSTs and syndications for 1031 investors.

What does a study cost, and what if you missed it?

Costs vary with building size and study depth, so get written quotes rather than relying on a rule of thumb. We have not verified a public cost benchmark.

If you skipped a study in the year you bought, you may be able to catch up later. The Form 3115 instructions list a change from an impermissible to a permissible depreciation method as an automatic change (DCN 7), and say a section 481(a) adjustment is ordinarily required. Whether a late study qualifies depends on the facts and your return history, so ask your CPA before you file anything.

Decision steps for a sponsor

Use these steps before closing, with your CPA:

1. Confirm the purchase contract date and what it means for the bonus rate.
2. Ask the CPA to estimate the first-year loss and who can use it, based on your investor mix.
3. Get two or three quotes, and check the preparer's qualifications.
4. Decide whether any election, such as the 40% option, helps your investors.
5. Model recapture at your expected sale year.
6. Tell investors in the offering documents what to expect, and avoid promising a tax benefit.

Our take

Our take: cost segregation is a good tool and a bad selling point. It makes the first-year K-1 look dramatic, but the investors who benefit are mostly those with passive income to absorb it. We would rather you explain that than let an investor discover it at tax time.

We would also keep the study out of the return projections. Treat it as a tax planning decision for the partnership, and let investors speak to their own CPAs. Our investor update guide covers how to flag K-1 timing.

Trade-offs and who this is not for

A study can cost real money and may create losses that investors cannot use. It can also complicate the K-1 for investors who are not used to partnership returns, and it can increase recapture on a fast sale. Lenders and buyers rarely care either way.

This approach is not for sponsors planning a very short hold with mostly investors who have no passive income, and it is not for anyone who wants guaranteed tax savings. It is also no substitute for a CPA. Common mistakes: assuming the building itself gets bonus depreciation, using the closing date instead of the contract date, promising investors they can offset salary, and forgetting that state rules can differ.

How DoorRaise fits in

DoorRaise helps sponsors raise equity for apartment buildings with 5+ units under Rule 506(b) or 506(c). The sponsor decides whether to order a study, with the deal's CPA. We are software, legal document preparation, escrow coordination and verification services, not a law firm, and we give no tax advice.

We charge 0% of the raise or profits, with three flat fees.

At setup, $500 forms the deal's LLC (including the registered agent), prepares investor documents from attorney-approved templates, opens an escrow account in the deal's name and runs accreditation checks on every investor. At closing, $5,000 is paid from the funds raised, only if the deal closes.

After that, $3,500 a year is paid from the property's income and covers bookkeeping synced from the property manager, the tax return and K-1s for every investor, payouts and investor updates, and final tax forms when you sell. State filing fees are included in the $5,000 closing fee. See real estate syndication fees.

Ready to raise? Create your free sponsor page or see pricing.

FAQ

Is cost segregation worth it for a small apartment building?

It depends on the purchase price, the study's cost, and whether your investors can use the losses. Ask your CPA to compare the first-year benefit with the cost and the recapture on sale.

Does bonus depreciation apply to the whole building?

No. It applies to qualified shorter-life property. The 27.5-year building structure is generally not eligible, so the study is what moves costs into eligible categories.

Can syndication losses offset my salary?

Usually not for limited partners. Passive losses generally offset only passive income, and the $25,000 allowance is not available to limited partner interests. Unused losses carry forward.

Will I owe tax when the property sells?

Possibly. Section 1245 treats gain on depreciated personal property as ordinary income up to the depreciation taken, and unrecaptured section 1250 gain is taxed at a maximum 25% rate. Your K-1 in the year of sale will show the amounts.

Can a study be done after the first year?

Often, yes, using Form 3115 and a section 481(a) adjustment, but it depends on the facts. Ask your CPA before filing.

Does DoorRaise order cost segregation studies?

No. The sponsor decides, with the deal's CPA. DoorRaise handles the tax return and K-1s for investors during the hold.

Sources

• IRS Publication 5653: Cost Segregation Audit Techniques Guide
• IRS Notice 2026-11: additional first year depreciation
• IRS news release on Notice 2026-11
• IRS Publication 946: How To Depreciate Property
• 26 U.S.C. 168 (Cornell LII)
• 26 U.S.C. 469: passive activity losses (Cornell LII)
• 26 U.S.C. 1245 (Cornell LII)
• IRS Topic 409: capital gains and losses
• IRS Rev. Proc. 2025-32 (2026 inflation adjustments)
• IRS Form 3115 instructions
• IRS Schedule K-1 (Form 1065) instructions

This post is general information as of October 2026, not tax, legal or investment advice. Examples are illustrative and use assumed rates. Talk to a CPA before you buy or invest. DoorRaise is not a law firm, broker-dealer, investment adviser or funding portal.