Common area maintenance (CAM) is the cost of shared areas such as parking lots, landscaping, and lighting, typically passed through to tenants.
In a NNN lease the tenant typically pays its share of CAM in addition to base rent, so the landlord's net income is not reduced by these costs. The details still matter, because leases may cap annual increases, exclude certain items, or require reconciliation to actual expenses once a year. For investors in multi-tenant centers, CAM disputes and uncollected reimbursements can reduce income. In a single-tenant property, CAM usually applies only if there is a shared parking area or other common facilities.