What is a base year error and why does it compound?

A base year error is when the landlord uses a lower-than-actual baseline figure for the base year in the escalation calculation. Because every subsequent year computes escalation from this understated starting point, even a small base year error inflates every future payment by the same dollar differential.

Does CAMAudit detect base year errors?

CAMAudit's escalation baseline check checks that expense escalation is calculated from the correct baseline and that the base year expenses have not been understated to inflate future-year payments. It flags both the error and the cumulative dollar overcharge.

Lease Terms & Dates

Base Year

Last updated: May 2026

A reference year, typically the first year of the lease or year of building occupancy, used in gross leases to establish a baseline for operating expenses. Tenants pay only increases above the base year's actual costs in subsequent years.

Firm impact

Base year errors are among the highest-dollar findings in gross and modified-gross lease audits. If the base year was set during a period of abnormally low occupancy or deferred maintenance, every subsequent year of escalation is inflated. I built CAMAudit because this error was nearly impossible to catch in spreadsheets at scale.

How this gets abused

A landlord sets the base year at 2020, when the building was largely vacant due to COVID-19 and operating costs were artificially depressed. In subsequent years, all increases above this deflated baseline were passed through to tenants, resulting in years of inflated expense-stop payments.

Practitioner note

Negotiate to gross up the base year expenses to at least 95% occupancy when advising clients at lease signing. This prevents inflated escalations caused by an artificially low base. At audit time, verify that the base year amount used in the reconciliation matches actual documented expenses for that year.