Cost segregation is technical, unglamorous, and easy to misunderstand. That is precisely why Cost Segregation Guys saw room to build a national service brand around speed, education, and defensible engineering.

Most founders go looking for a new technology or a fashionable market. Nathan Resnick found an opportunity in something older and less glamorous: the gap between what a building looks like and how the tax code treats the assets inside it.

To an investor, an apartment building, warehouse or hotel may feel like one asset. For depreciation purposes, it can contain many. Lighting, millwork, floor finishes, specialty wiring, furniture, fencing, paving and landscaping do not necessarily share the same useful life as the structure around them. A cost segregation study identifies and documents those differences so eligible components can be assigned to shorter recovery periods.

That technical exercise became the foundation for Cost Segregation Guys, where Resnick is a partner. The important entrepreneurial question is not simply how large that number is. It is how a service built on tax classifications, engineering detail, and professional judgment can be made understandable – and scalable.

Resnick had already built in another complicated category. He founded Sourcify, a Y Combinator-backed sourcing platform, and later moved to a board and advisory role. Manufacturing and tax depreciation are very different businesses, but the founder’s instinct is similar: when customers face a costly decision inside a confusing system, a company that provides a clear process may be better positioned to build customer trust.

Depreciation is fundamentally a timing system. The IRS generally allows an owner to recover the cost of income-producing property over a prescribed period. Under the general depreciation system, residential rental buildings are typically recovered over 27.5 years and nonresidential real property over 39 years. The structure remains on that long schedule, but qualifying personal property and land improvements may fall into shorter 5-, 7- or 15-year classes.

A cost segregation study does not manufacture a tax benefit. It moves eligible deductions to the years in which the law says those deductions belong. That distinction matters. A dollar deducted sooner can preserve cash for renovations, reserves, debt service, or another acquisition. The nominal deduction may be the same over time, but the present value can be very different.

This is why the firm’s value proposition is better understood as selling time rather than selling tax magic. The customer is paying to convert an undifferentiated building basis into a documented schedule of components, useful lives, and tax classifications. The output is a report; the service may allow eligible property owners to realize certain tax benefits sooner.

The timing opportunity grew more significant on July 4, 2025, when Public Law 119-21 was signed. The law made the 100% additional first-year depreciation deduction permanent for qualifying property acquired and placed in service after January 19, 2025. IRS guidance explains that qualifying property generally includes tangible property depreciated under MACRS with a recovery period of 20 years or less; it can include new property and certain used property.

The word “qualifying” means a great deal of work. A building does not become fully deductible because Congress restored 100% bonus depreciation. The potential benefit applies to eligible components identified within the property, subject to acquisition, placed-in-service, ownership, and other tax rules.

This can be especially relevant for short-term rental owners. A short-term rental property may contain qualifying components—such as certain furniture, appliances, flooring, landscaping, specialty electrical systems, and other personal-property or land-improvement assets—that can be separated from the building through a cost segregation study and assigned shorter recovery periods. Eligibility and the ability to use any resulting deductions will depend on the property’s facts, including how it is operated, the owner’s level of participation, and the applicable passive-activity and short-term rental rules.

Still, permanence changes the commercial conversation. During a phase-down, cost segregation could be marketed as a shrinking window. A permanent provision is more durable: investors can account for the strategy during acquisition underwriting, renovation planning, and annual tax forecasting. For a service company, that replaces some deadline-driven demand with a more predictable place in the property owner’s operating playbook.

The temptation in any technical service is to automate the most visible output and call that scale. But a fast estimate is not the same thing as a defensible study. The IRS publishes a Cost Segregation Audit Techniques Guide for examiners and notes that it is also useful to taxpayers and practitioners preparing studies. That alone signals the real standard: classifications must be traceable to facts, costs, and authority.

Cost Segregation Guys says its process combines engineering and tax expertise, virtual site visits, a structured intake, and audit-ready reporting. The scalable layer is the customer journey – proposal, document collection, status communication, and coordination with a client’s tax professional. The judgment layer still belongs to people who can analyze the property and support the conclusions.

This separation is a useful operating principle for founders in law, finance, compliance, medicine, and other expert-led fields. Standardize the handoffs, not the thinking. Use technology to remove waiting, duplicate data entry, and uncertainty. Keep the consequential decision tied to evidence and accountable professionals.

It also explains why support after delivery matters. In a low-stakes product, the sale ends when the customer receives the item. In a high-trust service, the customer’s anxiety may begin at delivery: Will my CPA understand this? What happens if the return is examined? Can the team explain the assumptions years later? A company that addresses those questions may provide ongoing support beyond delivering a report.

How a cost segregation study works

A credible cost segregation study is not a list of fixtures multiplied by a generic percentage. It is a property-specific reconciliation of tax law, physical facts and cost evidence. The exact workflow varies for a newly constructed building, an acquired property and a renovation, but a thorough engagement usually moves through the following stages.

1. Test feasibility before commissioning the full study.

The provider reviews the property type, acquisition or construction date, purchase price or project cost, land allocation, improvement history and current depreciation schedule. The aim is to estimate the portion of basis that might move to shorter lives and compare the likely timing benefit with the fee, ownership horizon and tax constraints. This preliminary estimate is a screening tool, not the final tax result.

2. Build the source-document file.

For an acquisition, useful records can include the closing statement, purchase agreement, appraisal, prior depreciation schedule, inspection reports, renovation invoices, floor plans and photographs. For new construction, the file may also include architectural and engineering drawings, contractor payment applications, change orders, job-cost ledgers and vendor invoices. Better contemporaneous records reduce the amount that must be estimated.

3. Verify what is actually at the property.

A physical or well-documented virtual review connects the paperwork to the building’s use and condition. The analyst identifies assets, distinguishes decorative or business-specific systems from structural systems, notes paving and site improvements, and records evidence with photographs or video. The IRS audit guide treats site inspection and photographic support as characteristics of a quality study.

4. Classify assets and assign costs.

Engineering analysis separates building systems from tangible personal property and land improvements, then applies the relevant statutes, regulations, and court authorities. Actual item costs are used when available; otherwise, recognized estimating methods may be used. The allocations should reconcile to the owner’s total depreciable basis rather than create costs that were never incurred.

5. Deliver a tax-ready audit trail.

A strong report explains the methodology, property facts, legal rationale, assumptions, cost sources, and reconciliation. It includes an asset schedule that the owner’s tax professional can translate into depreciation reporting. The underlying invoices, drawings, photographs, and calculations matter because the report may need to be understood years after it was prepared.

Tax strategies become dangerous when marketing removes the conditions. Accelerated depreciation can generate a large paper loss, but whether an owner can use that loss now depends on passive-activity, at-risk, basis, and material-participation rules, among others.

Rental activities are generally passive. One potential exception involves taxpayers who qualify as real estate professionals and materially participate; the IRS tests include more than 750 hours in qualifying real-property trades or businesses and more than half of the taxpayer’s personal-service time. Another frequently discussed route involves short-term stays: under Publication 925, an activity with an average customer-use period of seven days or less is not treated as a rental activity for the passive-activity rules. That does not automatically make every resulting loss deductible against wages. Material participation and the taxpayer’s full facts still matter.

There is also an exit side to the equation. Accelerating deductions reduces tax basis, and a later sale can trigger depreciation-recapture consequences. Holding period, expected appreciation, financing, suspended losses, and the cost of the study all belong in the decision.

For the service provider, this complexity creates an unusual sales advantage: a credible “not yet” or “not for this property” can be more valuable than an aggressive close. This distinction may help build confidence among property owners and support professional referral relationships with CPAs. In a referral-heavy category, restraint is not the opposite of growth. It is an acquisition channel.

The company says its reported $1 billion figure represents depreciation identified rather than tax refunds delivered. Actual tax impact varies by owner, property, timing and applicable rules. Viewed in context, the figure may illustrate the potential scale of depreciation timing considerations in real estate ownership.

The building does not change after a cost segregation study. The flooring, wiring and parking areas were there all along. What changes is the owner’s map of the property – and, potentially, the calendar on which deductions arrive.

That is the broader business Resnick and Cost Segregation Guys are building: a clearer interface for a dense system. Some specialized companies focus on making complex information clearer and more practical for customers evaluating their options.

The information provided in this article is for general informational and educational purposes only. It is not intended as legal, financial, medical, or professional advice. Readers should not rely solely on the content of this article and are encouraged to seek professional advice tailored to their specific circumstances. We disclaim any liability for any loss or damage arising directly or indirectly from the use of, or reliance on, the information presented.