Digital Realty Trust, Inc., is a Maryland corporation, formed on March 9,2004. It completed its initial public offering of common stock on November 3, 2004. It operates as a 'Real Estate Investment Trust'. The Company through its controlling interest in Digital Realty Trust, L.P. 'the Operating Partnership' and the subsidiaries of the Operating Partnership is engaged in the business of owning, acquiring, developing, redeveloping and managing technology-related real estate. Through its operating partnership, at December 31, 2012, it owned 117 properties, excluding three properties held as an investment in an unconsolidated joint venture, of which 92 are located throughout North America, 21 are located in Europe, three are located in Australia and one is located in Asia. Te Company's portfolio is diversified in major markets where corporate datacenter and technology tenants are concentrated, including the Boston, Chicago, Dallas, Los Angeles, New York Metro, Northern Virginia, Phoenix, San Francisco and Silicon Valley metropolitan areas in the United States, Amsterdam, Dublin, London and Paris markets in Europe and Singapore, Sydney and Melbourne markets in the Asia Pacific region. Is properties contain a total of approximately 21.9 million net rentable square feet, including approximately 2.4 million square feet of space held for development. As of December 31, 2012, its portfolio, excluding space held for development, was approximately 94.4% leased. It competes with numerous developers, owners and operators of real estate and datacenters, many of which own properties similar to them in the same markets in which its properties are located, including DuPont Fabros Technology, Inc., CoreSite Realty Corporation, CyrusOne Inc. and various local developers in the U.S., and Global Switch and various regional operators in Europe, Asia and Australia. Office properties in its submarkets are subject to various laws, ordinances and regulations, including regulations relating to common areas.