Mexican corporations that do not accept foreign investment (by stipulating as such in their by- laws) may acquire real property in the Prohibited Zone for any purpose. In contrast, while a Mexican company that allows foreign investment may also purchase real property within the Prohibited Zone, it can do so for non-residential purposes only, and provided that the corporation’s by-laws demand adherence to the Calvo Clause and that the corporation notifies the Secretary of Foreign Relations (SRE). Even more restrictive, foreign individuals and corporations cannot purchase real property located in the Prohibited Zone under any circumstance, but may purchase real property.