What is the base year stop in an office lease and how does it work?

The base year stop is the total operating expense per square foot the landlord absorbs on your behalf for the duration of your lease. It is set at the actual expenses for your first full calendar year (the base year), typically grossed up to 95% occupancy. In every subsequent year, if actual expenses exceed the stop, you pay your pro-rata share of the excess. If the base year was artificially low (landlord incentive year, construction discounts), you will face escalation charges in Year 2 even if expenses only increased modestly.

Which office lease operating expenses should not be grossed up?

Fixed expenses, those that do not vary with building occupancy, should never be grossed up. These include: property taxes (the taxing authority assesses the same amount regardless of occupancy), base building insurance premiums (the insurer charges based on replacement value, not occupancy), and management fee minimums. Only truly variable costs like electricity, gas, water, janitorial supplies, and cleaning labor scale with occupancy and qualify for the gross-up adjustment.

How do I audit an office lease operating expense escalation?

Request the landlord's annual operating expense reconciliation in detail, line-by-line expenses for both the base year and the current year. Identify every expense that increased, obtain supporting invoices for material increases, and separately analyze fixed vs. variable expenses in the gross-up calculation. CamAudit's gross-up violation detection rule automatically flags when fixed expenses have been included in the gross-up, generating a precise dollar overcharge figure.

What is the base year stop in an office lease and how does it work?

The base year stop is the total operating expense per square foot the landlord absorbs on your behalf for the duration of your lease. It is set at the actual expenses for your first full calendar year (the base year), typically grossed up to 95% occupancy. In every subsequent year, if actual expenses exceed the stop, you pay your pro-rata share of the excess. If the base year was artificially low (landlord incentive year, construction discounts), you will face escalation charges in Year 2 even if expenses only increased modestly.

Which office lease operating expenses should not be grossed up?

Fixed expenses, those that do not vary with building occupancy, should never be grossed up. These include: property taxes (the taxing authority assesses the same amount regardless of occupancy), base building insurance premiums (the insurer charges based on replacement value, not occupancy), and management fee minimums. Only truly variable costs like electricity, gas, water, janitorial supplies, and cleaning labor scale with occupancy and qualify for the gross-up adjustment.

How do I audit an office lease operating expense escalation?

Request the landlord's annual operating expense reconciliation in detail, line-by-line expenses for both the base year and the current year. Identify every expense that increased, obtain supporting invoices for material increases, and separately analyze fixed vs. variable expenses in the gross-up calculation. CamAudit's gross-up violation detection rule automatically flags when fixed expenses have been included in the gross-up, generating a precise dollar overcharge figure.

Office Lease CAM Audit Guide

Tenants in Office Lease structures face specific overcharge risks tied to how expenses are allocated and billed. CamAudit runs 12 forensic detection rules on your reconciliation statement to identify every recoverable dollar.

Formal Definition

A commercial lease structure used for multi-tenant office buildings, typically structured as a Full Service Gross (FSG) lease with Base Year expense stops, though some office markets (particularly suburban) use modified gross or NNN structures. Office leases in Class A high-rise buildings in gateway markets (New York, San Francisco, Chicago) are almost universally FSG with base year mechanics.

Expense Pass-Throughs

Base year: landlord covers all operating expenses bundled into rent. Years 2+: tenant pays pro-rata share of operating expenses exceeding the base year stop, often called "escalation rent" or "operating expense contributions." Escalation categories typically include: utilities, janitorial, management, maintenance, insurance, and property taxes.

CAM Calculation & Billing

Operating expense escalations are billed annually after year-end. The landlord compares actual total operating expenses to the base year stop (grossed up to 95% occupancy) and bills each tenant their pro-rata share of the excess. The gross-up calculation is the most technically complex and audit-significant element, only variable expenses should be adjusted.

Most Common Overcharge

Improper gross-up of fixed expenses, property taxes and insurance premiums are included in the gross-up calculation despite being fixed costs that do not vary with occupancy. This error lowers the effective base year stop (because the grossed-up base year is overstated) and inflates every subsequent year's escalation charge. For large office tenants, this error can generate tens of thousands of dollars in annual overcharges.

Common Industries

→Professional services (law, accounting, consulting)
→Financial services and banking
→Technology companies
→Healthcare administration
→Government and non-profit

Audit Focus

Identify and segregate fixed vs. variable operating expenses in the landlord's expense schedule. Confirm the gross-up is applied only to variable expenses (utilities, janitorial, maintenance). Verify that the base year was a "normal" operating year, not a construction year, major vacancy year, or landlord concession year that would create an artificially low stop. Review after-hours HVAC billing to ensure costs reflect actual utility expenses.

Red Flags to Watch

▶Property taxes or base insurance included in the gross-up adjustment
▶Base year that corresponds with a period of major construction or high vacancy
▶After-hours HVAC rates significantly above electricity cost
▶Management fee calculated on grossed-up expenses rather than actual net expenses
▶Operating expenses that do not reconcile to the building's general ledger

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Related Resources

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Frequently asked questions

This page provides general educational information. It is not legal advice and may not reflect the most current law in your state. Consult a licensed attorney for advice specific to your situation.