Operating Expense Budgeting for CAM: A Bottom-Up Methodology
The Cost of a Bad Budget
A property controller at a 200,000 SF office building set the 2025 CAM estimate by taking the 2024 estimate and adding 3%. That estimate was $8.50/SF. Actual expenses came in at $9.85/SF — a 15.9% miss that generated $270,000 in aggregate true-up invoices across 14 tenants.
Three tenants requested formal audits. Two delayed payment for 90+ days. One used the large true-up as leverage in a renewal negotiation that resulted in a $0.50/SF rent concession over a 5-year term — $500,000 in lost revenue.
The root cause wasn't rising costs. It was a lazy budget. Property taxes had increased 8% from a reassessment the controller knew about in October. Insurance renewed at 12% higher. A new janitorial contract kicked in at 7% above the prior vendor. Every one of these was knowable before the budget was set.
Bottom-Up vs. Top-Down Budgeting
Top-Down (Don't Do This)
Take last year's total, add an inflation factor, divide by SF. This is what most property managers do. It's fast, easy, and wrong — because it treats every expense category the same, ignores known changes, and compounds errors year after year.
Bottom-Up (Do This)
Budget each expense category individually based on its specific cost drivers. Then aggregate to get the building total. This takes more time upfront but produces estimates within 3–5% of actual — which is the difference between smooth collections and dispute-riddled Q1.
Category-by-Category Budgeting
Property Taxes
Cost driver: Assessed value x tax rate
This is the most predictable large expense. You know the assessed value (it's public record). You know the tax rate (published by the taxing authority). Multiply them.
What to account for:
- Pending protests or appeals — budget the current assessed amount, not the hoped-for reduction
- Supplemental assessments from recent improvements or sales
- New special district levies or bond measures passed in the November election
- Tax rate changes published by the county
Example:
- Current assessed value: $28,500,000
- Tax rate: 1.12% (county) + 0.15% (special district) = 1.27%
- Budget: $28,500,000 x 1.27% = $361,950
- Prior year actual: $342,000 (assessed value was $27,100,000)
- Variance: +$19,950 (+5.8%)
Insurance
Cost driver: Policy premiums at renewal
Insurance renews once per year. If your budget period starts after renewal, you have the actual number. If renewal falls mid-budget-year, get a preliminary quote from your broker 60 days before budget deadline.
Example:
- Current policy: $67,000/year (expires March 1)
- Broker quote for renewal: $74,500 (11.2% increase)
- Budget: $74,500
- Do not budget $67,000 + 3% inflation = $69,010 (you'd miss by $5,490)
Utilities
Cost driver: Consumption x rate
Get rate schedules from each utility provider. Most publish rate increases in advance. For consumption, use the trailing 12-month average adjusted for occupancy changes.
Adjustments to make:
- Occupancy changes: a major tenant move-in adds load
- Rate increases: check published tariff schedules
- Equipment changes: new LED lighting reduces electric; a new boiler affects gas
- Weather: use a 3-year average of degree days rather than a single year
Example — Electric:
| Factor | Value |
|---|---|
| 2025 actual consumption | 1,890,000 kWh |
| Occupancy adjustment (+6%) | +113,400 kWh |
| Rate (current) | $0.094/kWh |
| Published rate increase (4%) | $0.098/kWh |
| 2026 Budget | $196,333 |
| 2025 actual cost | $177,660 |
| Variance | +$18,673 (+10.5%) |
Janitorial
Cost driver: Contract rate or hourly labor + supplies
If you have a janitorial contract, the budget is the contract amount. If the contract renews during the budget year, get the proposed rate from the vendor. Day porters, extra event cleaning, and supply cost increases are the variables.
Example:
- Base contract: $13,500/month = $162,000/year
- Contract renewal in July at 5% increase: $14,175/month for 6 months
- Budget: ($13,500 x 6) + ($14,175 x 6) = $166,050
- Plus supplies estimate: $8,500
- Total budget: $174,550
Repairs and Maintenance
Cost driver: Historical average + known projects
R&M is the hardest category to budget because it includes both routine maintenance and unpredictable repairs. Use a 3-year rolling average as the base, then add any known projects.
Example:
| Component | Amount |
|---|---|
| 3-year average R&M spend | $92,000 |
| Known: elevator service contract increase | +$4,200 |
| Known: parking lot seal-coating (scheduled) | +$18,000 |
| Inflation on remaining (3%) | +$2,100 |
| R&M Budget | $116,300 |
| Prior year actual | $89,000 |
The parking lot project pushes the budget 30% above prior year. Document this in the budget memo — it prevents questions when tenants see the estimate increase.
Management Fees
Cost driver: Fee percentage x base amount per management agreement
This is a calculation, not an estimate. Determine the base (usually gross revenue or total operating expenses), apply the percentage, and that's the number.
Example:
- Management fee: 4% of effective gross revenue
- Projected EGR: $3,200,000
- Management fee budget: $128,000
Landscaping, Security, Elevator, Fire/Life Safety
These are typically contract-driven. Pull the current contract, check the renewal terms, and budget the contracted amount. Most multi-year service contracts include annual escalators of 2–4%.
The Budget Assembly
Once you've built each category, assemble the total and convert to per-SF estimates:
| Category | 2025 Actual | 2026 Budget | $ Change | % Change |
|---|---|---|---|---|
| Property Taxes | $342,000 | $361,950 | +$19,950 | +5.8% |
| Insurance | $67,000 | $74,500 | +$7,500 | +11.2% |
| Utilities | $210,000 | $228,333 | +$18,333 | +8.7% |
| Janitorial | $156,000 | $174,550 | +$18,550 | +11.9% |
| R&M | $89,000 | $116,300 | +$27,300 | +30.7% |
| Management Fee | $118,000 | $128,000 | +$10,000 | +8.5% |
| Landscaping | $42,000 | $43,700 | +$1,700 | +4.0% |
| Security | $48,000 | $49,500 | +$1,500 | +3.1% |
| Total | $1,072,000 | $1,176,833 | +$104,833 | +9.8% |
For a 120,000 SF building:
- 2025 actual per SF: $8.93
- 2026 budget per SF: $9.81
- Per SF increase: $0.88 (+9.8%)
Aligning the Budget with Recovery Projections
The budget tells you what expenses will be. The recovery projection tells you how much you'll collect from tenants. The gap between them is your NOI exposure.
Recovery leakage sources to account for:
- Vacant space (no tenant to bill)
- Capped tenants (expense growth exceeds their cap)
- Base year tenants with low base years (they only pay the excess)
- Excluded categories per specific leases
- Admin fee structures that don't cover all expenses
Example recovery projection:
| Metric | Amount |
|---|---|
| Total budgeted operating expenses | $1,176,833 |
| Less: non-recoverable items | ($35,000) |
| Recoverable pool | $1,141,833 |
| Less: vacancy (8% of pool) | ($91,347) |
| Less: cap limitations (est.) | ($22,000) |
| Less: base year absorption | ($45,000) |
| Projected recovery | $983,486 |
| Recovery ratio | 86.1% |
If ownership expects a 92% recovery ratio, there's a $67,000 gap to explain. That conversation is much easier to have during budgeting than after year-end when the cash is already not there.
When to Set the Budget
Budget timing matters because it determines the accuracy of your inputs:
| Budget Deadline | Pro | Con |
|---|---|---|
| October (for Jan 1 year) | Aligns with most corporate planning cycles | Q4 actuals not yet known; insurance renewal may not be final |
| November | Most contract renewals known | Property tax appeals may still be pending |
| December | Best data available | Tight timeline to calculate and communicate new estimates |
Aim for November. You'll have 10 months of actuals, most contract renewals will be negotiated, and you'll still have time to calculate tenant estimates and send notice letters by January 1.
Communicating the Budget to Tenants
Tenants don't receive your full budget — they receive a new CAM estimate for the coming year. But the estimate change should be explainable by reference to the budget.
Best practice: Send a brief cover letter with the new estimate that explains the largest drivers of change. One paragraph, three bullet points maximum.
Your 2026 CAM estimate is $4.91/SF/month, an increase of $0.44/SF from 2025. The primary drivers are: (1) property tax reassessment (+$0.17/SF), (2) scheduled parking lot maintenance (+$0.15/SF), and (3) janitorial contract renewal at market rates (+$0.08/SF).
This one paragraph prevents dozens of phone calls and sets the expectation before the tenant opens their first January invoice.
How CapVeri Supports Budget Development
CapVeri's GL analysis engine gives you the historical trending data you need for bottom-up budgeting — actual expenses by category, per-SF metrics, and year-over-year comparisons across your portfolio. When your budget turns into next year's estimates, the platform calculates per-tenant amounts using each tenant's specific lease terms, caps, base years, and exclusions.
Related Resources
- CAM Variance Analysis — What to do when actuals diverge from budget
- CAM Estimate Forecasting — Setting accurate mid-year estimates
- Recovery Ratio Analysis — Measuring whether your budget converts to collections
- CAM Reconciliation vs. Estimate — How the budget cycle connects to reconciliation