Best Cost Segregation Companies of 2026

The CPA-default firm. 30,000+ studies, biggest CCSP-certified team in the country, A+ BBB. Their staff helped write the IRS Audit Techniques Guide. Not "follow." Wrote. Real credibility on complex commercial and Tax Court defense. KBKG also runs costsegregation.com, their own DIY tool starting at $495 — meaning KBKG itself agrees not every property needs the $5K+ treatment.

Best in class for complex commercial and industrial. Overkill and overpriced on a standard rental house. KBKG's own DIY tool is the better fit for that.

• Industrial properties. Specialized equipment, process piping, conveyor systems. An engineer walking the floor catches things satellite imagery misses.
• Large commercial. Office, retail, hospitals. Misallocating $200K of components on these costs real money.
• Institutional investors. When your LP deck needs to say "KBKG" in the tax strategy section.

• 25+ years, 30,000+ studies, A+ BBB rating
• Staff helped author the IRS Audit Techniques Guide
• Engineers have served as expert witnesses in Tax Court
• DIY option at costsegregation.com for budget-conscious investors

• $5K–$15K+ pricing — most expensive option for most investors
• 4–8 week turnaround is the slowest category
• Mandatory site visits add cost and scheduling friction
• Their own DIY tool undercuts the premium pricing argument

Every industry has That Guy on every podcast and forum thread. In cost segregation, that's Yonah Weiss. He founded R.E. Cost Seg and he's everywhere: LinkedIn, BiggerPockets, podcasts you've never heard of. That level of visibility usually makes us suspicious. Yonah knows his stuff. His content teaches instead of just generating leads.

The company has done 15,000+ studies and claims an NPS above 90. The $895 Rapid Report is the product. It comes back in under a week. Every STR investing forum we checked points here first. They handle furnished rental FF&E better than most firms. If your Airbnb is full of furniture and decor, that's 5-year property, and a lot of firms just don't capture all of it.

Heads up on the upsell: their full engineering study is $5,000+. At that price you're paying KBKG money. Stick with the Rapid Report.

Own an Airbnb? This is probably your best bet. $895 Rapid Report, CPAs are comfortable filing it, and Yonah's team knows STR inside and out.

• STR / Airbnb owners. Their wheelhouse. The STR specialization isn't marketing fluff. They handle furnished rental FF&E better than most firms.
• BiggerPockets community. If a podcast or BP thread sent you here, Yonah's name probably came up. Trust earned, not bought.
• Residential investors. The $895 Rapid Report makes the math work on smaller properties where a $5K study never penciled out.

• $895 Rapid Report — best value in the traditional tier
• Best STR specialization we found anywhere
• 15,000+ studies, high satisfaction across the board
• Yonah's content actually educates (rare for this industry)
• Claim 100% audit defense success rate

• Full studies hit $5,000+ — same price as KBKG at that point
• Residential and STR only — don't bother calling about an office building
• Rapid Report is software-driven, not a full engineering analysis
• No longer the fastest option — automated providers deliver in hours

Two things stand out. First, they refund you if the IRS finds a problem with their work. Most firms offer "audit defense," which means a letter and maybe a call. Seneca puts money on the line. Second, they're the only firm on the list where hospitality is the core business instead of a side line. Hotels, resorts, restaurants, conference centers. Commercial kitchens, specialized HVAC, fast-turning FF&E — they know the breakdowns.

If you own a hotel, restaurant, or hospitality property, start here. Their refund guarantee backs it up.

• Hotel / resort owners. The most specialized hospitality option.
• Restaurant owners. Restaurant buildouts have weird component mixes. Seneca knows them cold.
• Commercial property owners. Strong across the board. Rush service helps near filing deadlines.

• Refund guarantee on audit issues — rare and meaningful
• Only firm with a real hospitality specialization
• Rush service in about a week
• Strong commercial and industrial track record

• Pricing not published (estimated $3K–$10K)
• No residential or STR focus
• Standard turnaround 2–4 weeks
• Smaller firm, less name recognition

CSSI claims 60,000+ studies, which would make them the highest-volume firm on this list. Around since 2003. Franchise model out of Indianapolis. A+ BBB. Forum sentiment splits by property type: commercial clients post happy reviews, residential clients post complaints about inflated savings estimates and aggressive sales follow-up.

Legit firm. Good at multifamily and commercial. The pricing, turnaround, and sales reputation kept them at #5.

• Multifamily owners. Their strongest category.
• Commercial property owners. Office, retail, mixed-use. Franchise model means a local office.
• Investors who want a big name. 60,000 studies and 23 years checks that box.

• 23+ years in business with A+ BBB rating
• National coverage through regional franchise offices
• Strong multifamily and commercial track record

• $5K–$15K+ pricing puts them in the premium tier
• Forum reports of initial estimates exceeding final results
• Sales follow-up described as aggressive by multiple users
• Google review count low relative to 60,000+ study claim

Big tax specialty firm out of Indianapolis. Cost seg is one of several services (R&D credits, 179D, fixed asset reviews). Midwest CPAs talk about them. Individual investors don't, because McGuire Sponsel doesn't market to them. It's a CPA-referral business.

Good firm. Your CPA has to recommend them. You won't find them on your own.

• CPA-referred investors. If your accountant sent you here, trust that.
• Multifamily / commercial. Their bread and butter.
• Multiple tax services. R&D, 179D, fixed assets. One firm covers it if you need all of them.

• Strong CPA reputation, especially Midwest
• Multi-service firm
• Accountants describe reports as thorough

• Not set up for individual investors
• Pricing not published, likely $5K–$15K+
• Almost no public review data
• No STR or residential specialization

Their whole pitch: nobody comes to your property. You do a "Smart Tour" yourself — a guided FaceTime walkthrough — combined with satellite imagery and assessor data. Mid-market pricing. 2–3 week turnaround.

Sits between full-service and automated. Decent middle ground if you want a human involved without paying $8K.

• Out-of-state investors. Property 2,000 miles away? Smart Tour makes sense here.
• Mid-market residential. More than pure automation, less than Tier 1 pricing.
• Investors who want a human in the loop. The video walkthrough adds reassurance.

• No-site-visit model keeps costs lower than traditional
• Smart Tour adds a human element
• 2–3 week turnaround faster than most Tier 1
• Good fit for out-of-state investors

• $2K–$8K is still 3–10× what automated providers charge
• You have to do the video walkthrough yourself
• Unclear how much the video adds vs. assessor data
• No publicly disclosed study volume

The firm CPAs refer to when they want white-glove treatment on a commercial deal. No Instagram. No webinars. Pure CPA referral relationships since 2004.

If your accountant said "use Capstan," trust it. Otherwise this isn't for you.

• CPA-referred commercial owners. Strong endorsement if your accountant points here.
• Large commercial / industrial. Their sweet spot. Skip for residential.
• White-glove preference. The firm feels like a law office, not a tech startup.

• Strong CPA referral network
• 20+ years in business, focused on commercial
• Detailed engineering methodology with site visits

• Premium pricing ($5K–$10K+ estimated)
• 3–5 week turnaround
• No residential or STR coverage
• Basically requires a CPA introduction

Not a pure cost seg shop. In-house engineers and CPAs, offices in four states, also runs HOA reserve studies. If you need cost seg and a reserve study for a condo association, the one-stop-shop angle could be useful.

Worth a look if you need multiple engineering services. For cost seg alone, we want to see more track record.

• HOA / condo associations. Reserve study + cost seg in one firm.
• Engineers + CPAs in-house. Both under one roof, fewer handoffs.
• Multi-state owners. Offices in MI, CA, PA, CO.

• In-house engineers and CPAs — rare combination
• Also does HOA reserve studies
• Four office locations

• Founded 2020 — relatively new
• Cost seg pricing not prominently published
• Very little public review data
• More specialized options if you only need cost seg

Cost seg arm of O'Connor & Associates, a big Texas property tax firm. O'Connor's main business is property tax protests. Cost seg runs on top of that infrastructure.

Cheap and backed by a real firm. Worth a call if you're price-sensitive. Pin them down on what the $500 tier actually delivers before paying.

• Budget-conscious investors. $500 starting price is one of the lowest on this list.
• Texas property owners. O'Connor is huge in Texas property tax. Natural extension.
• Established parent preference. Decades of property data infrastructure.

• Starting price around $500 — very competitive
• Backed by O'Connor & Associates, a large firm
• Existing property data infrastructure

• Unclear what the $500 tier actually includes
• Very little public review data
• Cost seg isn't their core business
• Process details vague on the website