In many cities, developers may be unable to pass office development linkage fees to either former landowners or tenants. Potential tenants will not accept exaction fees if they are sensitive to rental increases and if they can move to alternate locations. A survey of office users in the Philadelphia central business district shows the extent of user mobility. A financial analysis using Philadelphia data indicates that linkage fees substantially reduce developer returns when office users are mobile. As a result, such fees eventually curtail development. Before they implement linkage fee programs, therefore, cities should consider the sensitivity of demand for office space and the likelihood that developers can survive with lower profit margins.