Operating expenses are where most deals go sideways. Every dollar you underestimate in expenses translates directly into NOI overstatement, which at a 6% cap rate magnifies into ~$17 of valuation error per missing dollar.

The good news: operating expenses are finite. There are about 15 categories that matter, they have well-known industry benchmarks by asset class, and once you know what should be there, it takes 5 minutes to verify whether a T-12 is complete and honest.

Here are every operating expense category you should look for on a commercial property T-12:

Fixed expenses (mostly outside your control)

1. Property taxes The largest single line on most commercial T-12s. In Florida, typically 1.5-2.2% of assessed value annually. Critical: property taxes reassess after a sale. The current owner's tax bill is based on their old basis. Your post-sale bill will almost always be higher — often 20-50% higher on Florida deals because the assessed value jumps to your purchase price.

Always recalculate taxes using your purchase price × the millage rate, not the seller's historical number.

2. Property insurance Has been rising rapidly in Florida (and anywhere near a coast). Many Florida properties have seen insurance double or triple in the last 3 years due to hurricane exposure. Get a real quote from an insurance broker as part of due diligence — do not trust the T-12 number.

3. Property management fee If the current owner self-manages, the T-12 shows zero management fee. This is a trap. Always underwrite a market management fee — typically:

| Asset type | Management fee | |---|---| | NNN retail (single tenant) | 1-3% of EGI (minimal work) | | Multi-tenant retail | 3-5% of EGI | | Office | 3-5% of EGI | | Multifamily | 4-8% of EGI | | Self-storage | 5-7% of EGI | | Hotel | 3-4% of revenue (plus incentive) |

Why do this even if you'll self-manage? Because your time isn't free, and because when you eventually sell, the next buyer will underwrite with a market management fee. If you claim zero management today, you're just pulling forward valuation that won't exist at exit.

Variable expenses (partly under your control)

4. Utilities — common area electric, water, sewer, gas, trash. On NNN properties, most utilities are on tenant meters, so you only pay common area. On gross leases, you pay everything.

5. Repairs & maintenance (R&M) — ongoing routine maintenance. Plumbing calls, light fixtures, paint touch-ups, minor HVAC service. Typically 3-8% of EGI depending on building age. Watch for one-time spikes (Lesson 3).

6. Grounds / landscaping — mowing, mulch, irrigation, seasonal cleanup. $1,000-5,000/year for small commercial, more for larger sites.

7. Snow removal (north of Florida) — seasonal, lumps into the winter months.

8. Pest control — critical in Florida for any food-service tenant. $500-2,000/year typical.

9. Janitorial / cleaning — common area cleaning. Mostly relevant for office and multi-tenant retail.

10. Turnover / make-ready costs — paint, carpet, cleaning between tenants. Relevant for multifamily mostly. Multifamily typical: $500-1,500 per turn.

11. Marketing / advertising / leasing — marketing vacant space, leasing commissions on new leases. Relevant whenever the property has turnover.

12. Legal and professional — accounting, legal, minor consulting. Typically $1,000-5,000/year for a small commercial property.

13. Administrative / office — postage, supplies, fees for accounting software, bank fees.

Reserves (almost always missing from the T-12)

14. CapEx reserves — money set aside for future large capital expenditures (roof replacement, parking lot resurfacing, HVAC replacement). Virtually never appears on a T-12 because it's a reserve, not a current-period expense. You MUST add this to normalized NOI.

Typical CapEx reserve:

| Asset type | Annual CapEx reserve | |---|---| | Multifamily | $250-400 per unit | | NNN retail (absolute) | $0 (tenant pays) | | Multi-tenant retail | $0.15-0.30 per SF | | Office | $0.25-0.40 per SF | | Industrial | $0.10-0.20 per SF | | Self-storage | $0.10-0.20 per SF |

15. Replacement reserves / deferred maintenance escrow — separate from CapEx reserves. Covers immediate deferred maintenance found during due diligence. Typically tied to specific DD findings.

Expense ratio benchmarks

The fastest sanity check: divide total operating expenses by EGI and compare to the benchmark for your asset class.

| Asset class | Typical expense ratio | |---|---| | Single-tenant NNN (absolute) | 2-8% | | Single-tenant NNN (with reserves) | 5-12% | | Multi-tenant retail (NNN) | 25-35% (landlord collects CAM but still pays expenses upfront) | | Multi-tenant retail (gross) | 35-50% | | Office | 35-50% | | Multifamily (Class A) | 35-45% | | Multifamily (Class B/C) | 45-55% | | Self-storage | 30-45% | | Hospitality | 60-75% | | Industrial | 10-25% (NNN) |

The 6 most commonly missing line items

These are the expenses brokers "forget" to include most often, in rough order:

1. Management fee

Mentioned above — the biggest single lie in CRE underwriting. Half of small commercial OMs show zero management fee. Add one.

2. CapEx reserves

Almost never in the T-12. Must be added manually.

3. Payroll taxes (on multifamily)

If a property has on-site staff (leasing agent, maintenance tech), the T-12 shows their wages but often forgets payroll taxes, workers comp, and benefits. Add 20-30% on top of wages.

4. Post-sale property tax increase (Florida especially)

Taxes are reassessed on sale. The current owner's tax bill is often dramatically below what yours will be. Recalculate.

5. Increased insurance premiums

Florida hurricane exposure has doubled or tripled insurance in many submarkets. Get a real quote.

6. Marketing and leasing commissions on turnover

If the T-12 reflects a year with no turnover, it shows zero leasing costs. In a normal year with one or two tenants rolling, you'll have marketing and brokerage commission expenses. Underwrite them.

A real-world cleanup example

Let's take a small multifamily 12-unit property in Orlando. Broker's OM shows:

Gross rent:         $240,000
Vacancy (5%):      ($12,000)
EGI:                $228,000

Expenses:
  Property taxes:    $12,000
  Insurance:          $3,600
  R&M:                $6,000
  Landscaping:        $1,800
  Utilities:          $4,200
  Trash:              $1,200
  Legal:                $600
  Total OpEx:        $29,400

NOI:               $198,600

Expense ratio: $29,400 / $228,000 = 12.9%.

12.9% on a multifamily deal is impossible. Multifamily runs 35-55%. Let's rebuild.

Adjustments:

Management fee (missing): 6% of EGI = $13,680
CapEx reserves (missing): $300 × 12 units = $3,600
Post-sale property tax increase: If sale price is $2.4M and millage is 1.8%, new tax = $43,200. That's $31,200 MORE than the T-12 shows.
Insurance update (stale): Florida multifamily insurance has probably risen. Get a real quote; let's assume $6,500 instead of $3,600. Extra $2,900.
Turnover marketing/make-ready: $500 per unit × 3 turns/year = $1,500

Adjusted expenses: $29,400 + $13,680 + $3,600 + $31,200 + $2,900 + $1,500 = $82,280

Adjusted NOI: $228,000 − $82,280 = $145,720

Adjusted expense ratio: $82,280 / $228,000 = 36.1% ✓ (within the benchmark range)

The broker's NOI of $198,600 was off by $53,000. At a 6% cap rate, that's a $883,000 valuation error.

This is not a rare case. This is a typical case on small commercial deals where the seller is trying to dress up an unremarkable property as a 5-cap when it's really a 9-cap.

What to take away

Operating expenses are finite — 15 main categories cover almost everything
Know the expense ratio benchmarks for your asset class and use them as a sanity check
The 6 most commonly missing items are: management fee, CapEx reserves, payroll taxes on multifamily, post-sale tax increases, updated insurance, and turnover marketing
Expense ratios that seem too good to be true always are
Rebuilding expenses from scratch is worth hundreds of thousands of dollars in valuation accuracy

Next lesson: how to compare the broker's pro forma against the T-12 reality and spot the growth assumptions that are pure fantasy.

Operating Expenses — Categories, Benchmarks, and Missing Line Items