Office Building Classes: A, B, and C
Office buildings are commonly graded into Class A, Class B, and Class C tiers based on age, location, finish quality, and building systems. Class A buildings are newer or recently renovated, well-located, and command the highest rents; Class B buildings are older but functional and well-maintained, often serving as a value alternative; Class C buildings are typically older and lower-cost, frequently targeted for renovation, repositioning, or redevelopment.
Lease Terms and Tenant Improvement Allowances
Office leases are typically longer than other property types—often five to ten years or more for larger tenants—reflecting the cost both sides incur to relocate or re-tenant space. Landlords commonly provide a tenant improvement (TI) allowance, a negotiated dollar amount per square foot to help the tenant build out its space, along with leasing commissions paid to brokers and sometimes a period of free rent as further inducement.
Because these concessions can be substantial, practitioners often evaluate a lease using net effective rent, which levels out concessions across the lease term to show the landlord's true average annual rent.
CBD vs Suburban Office
Central business district (CBD) office buildings are concentrated in downtown cores, offering transit access, density of amenities, and prestige, but often at a higher cost and with commute-related friction for employees. Suburban office properties, frequently arranged in office parks, typically offer surface parking, lower rents, and easier highway access, appealing to tenants prioritizing cost and employee commute convenience over downtown prestige.
How It Makes Money
Office income is built on base rent under multi-year leases, often with contractual annual escalations, plus reimbursement of operating expenses depending on whether the lease is structured as gross, modified gross, or net. After subtracting operating expenses, capital expenditures for tenant improvements, and leasing commissions, the remaining net operating income reflects the building's cash-generating capacity—but office NOI is more sensitive than most property types to the timing and outcome of lease rollovers.
Work-From-Home and Vacancy Risk
The shift toward hybrid and remote work has reduced the average square footage many companies need per employee, contributing to elevated vacancy across much of the office sector. The effect has been uneven: well-located, highly amenitized buildings have generally seen a flight to quality, retaining occupancy and rents better, while older, lower-class buildings in weaker locations have experienced the steepest and most persistent vacancy increases.
Typical Tenants
- Professional services firms (law, accounting, financial advisory)
- Technology and software companies
- Corporate headquarters and regional offices
- Government agencies and nonprofits
- Medical and specialty office users (medical office subtype)
Key Underwriting Metrics
- Weighted average lease term (WALE) remaining across the rent roll
- Tenant credit quality and industry concentration
- Lease rollover schedule (% of NOI expiring per year)
- TI/leasing commission cost per square foot for renewals vs new leases
- Occupancy and absorption trends in the submarket
Major Risks
- A large tenant vacating at lease expiration (rollover risk)
- Rising TI and leasing commission costs to re-tenant space
- Structural demand decline from hybrid/remote work
- Obsolescence versus newer, more amenitized competitors
- Long releasing downtime in soft markets
Typical Lender Fit
- Banks and credit unions for well-leased, moderate-leverage stabilized assets
- Life insurance companies for trophy/Class A assets with strong credit tenancy
- CMBS for larger, diversified office loans and portfolios
- Debt funds/bridge lenders for transitional or lease-up repositioning
Net Effective Rent (NER)
NER = [(Base Rent/SF × Lease Term) − Free Rent Value − TI Allowance] ÷ Lease Term
- Base Rent/SF
- — Contractual annual rent per square foot before concessions ($/SF/yr)
- Lease Term
- — Length of the lease (years)
- Free Rent Value
- — Total dollar value of any free-rent (abatement) period, per square foot ($/SF)
- TI Allowance
- — One-time tenant improvement allowance the landlord funds, per square foot ($/SF)
Net effective rent levels out concessions like free rent and tenant improvement allowances over the full lease term, showing the landlord's true average annual rent economics rather than the headline base rent.
Worked example: A tenant signs a 5-year lease at $35/SF/year with 2 months of free rent and a $15/SF TI allowance. Total gross rent = $35 × 5 = $175/SF. Free rent value = $35 × (2/12) = $5.83/SF. NER = ($175 − $5.83 − $15) ÷ 5 = $30.83/SF/year.
Office Building Classes
| Class | Description | Typical Location | Typical Rent Position |
|---|---|---|---|
| Class A | Newest or most recently renovated buildings with high-end finishes, modern systems, and strong amenities | Prime CBD or premier suburban nodes | Commands the highest rents in the market |
| Class B | Solid, functional buildings that are older or less amenitized but well-maintained | CBD or suburban | Mid-tier rents; often a value alternative to Class A |
| Class C | Older buildings with basic systems and finishes, often needing capital investment | Secondary locations | Lowest rents; frequent candidates for renovation or redevelopment |
Rollover Risk Drives Office Valuation More Than Almost Any Other Property Type
Because office leases are long but concentrated among relatively few tenants, a single large tenant's decision not to renew can swing occupancy and cash flow dramatically. Underwriting office debt requires modeling the full lease rollover schedule—not just current occupancy—and stress-testing re-leasing costs and downtime, which have both risen in many markets since the shift to hybrid work.
Module Check
What is a Tenant Improvement (TI) allowance in an office lease?