Office properties cover a wide range of buildings, from single tenant properties designed for offices to multi-tenant buildings. Leases are typically negotiated for a long-term period and can include a building purchase option. In long-term leases, the total rent is often locked at the initial negotiated rate for the whole period and doesn’t consider market changes. Significant adjustments can therefore occur when leases expire. Economic drivers are employment growth, as well as local economy state (some industries are concentrated in one region). Commercial real estate investments in office buildings present a risk: an economic crisis may lead to the bankruptcy of the businesses. To avoid such a disaster, investors can rent their office to multiple tenants, so that the risk is split amongst them and one single tenant cannot therefore endanger the whole investment if he remains unable to pay.