Organization	12 Months Ended
Dec. 31, 2012
Organization
Organization	Note 1. Organization CommonWealth REIT is a real estate investment trust, or REIT, formed in 1986 under the laws of the State of Maryland. Our primary business is the ownership and operation of real estate, which primarily includes office buildings located throughout the United States. At December 31, 2012, our consolidated portfolio (excluding properties classified as held for sale) included 440 properties with a total of approximately 71,901,000 square feet of leasable space. Our wholly owned portfolio includes 345 properties with a combined 47,309,000 square feet (excluding properties owned by Select Income REIT, or SIR, our consolidated subsidiary, and properties classified as held for sale), including: (i) 50 office buildings with a combined 21,109,000 square feet located in central business district, or CBD, locations, (ii) 218 buildings with a combined 17,410,000 square feet located in suburban locations and (iii) 77 industrial & other buildings with a combined 8,790,000 square feet. Eleven of our wholly owned properties are CBD office and industrial properties with a combined 1,759,000 square feet that are located in Australia. On March 12, 2012, our then wholly owned subsidiary, SIR, completed an initial public offering of 9,200,000 of its common shares, or the SIR IPO. SIR intends to be taxable as a REIT. As of December 31, 2012, SIR owned 95 of our consolidated properties with a combined 24,592,000 square feet. These properties include 57 properties with a combined 17,773,000 square feet located on the island of Oahu, HI, of which a large majority consists of land which is net leased to industrial and commercial tenants under long term ground leases. As of December 31, 2012, SIR also owned 38 single tenant, net leased suburban office and industrial properties with a combined 6,819,000 square feet located throughout the mainland United States. As of December 31, 2012, we owned 22,000,000, or approximately 56.0%, of SIR's outstanding common shares, and SIR remains one of our consolidated subsidiaries. See Note 10 for additional information regarding the SIR IPO. As of December 31, 2012, we also owned 18.2% of the outstanding common shares of Government Properties Income Trust, or GOV, a Maryland REIT that primarily owns properties located throughout the United States that are majority leased to government tenants. GOV was our wholly owned subsidiary until its initial public offering, or the GOV IPO, in June 2009 when it became a separate public entity.

Organization

12 Months Ended

Dec. 31, 2012

Note 1. Organization

CommonWealth REIT is a real estate investment trust, or REIT, formed in 1986 under the laws of the State of Maryland. Our primary business is the ownership and operation of real estate, which primarily includes office buildings located throughout the United States. At December 31, 2012, our consolidated portfolio (excluding properties classified as held for sale) included 440 properties with a total of approximately 71,901,000 square feet of leasable space. Our wholly owned portfolio includes 345 properties with a combined 47,309,000 square feet (excluding properties owned by Select Income REIT, or SIR, our consolidated subsidiary, and properties classified as held for sale), including: (i) 50 office buildings with a combined 21,109,000 square feet located in central business district, or CBD, locations, (ii) 218 buildings with a combined 17,410,000 square feet located in suburban locations and (iii) 77 industrial & other buildings with a combined 8,790,000 square feet. Eleven of our wholly owned properties are CBD office and industrial properties with a combined 1,759,000 square feet that are located in Australia.

On March 12, 2012, our then wholly owned subsidiary, SIR, completed an initial public offering of 9,200,000 of its common shares, or the SIR IPO. SIR intends to be taxable as a REIT. As of December 31, 2012, SIR owned 95 of our consolidated properties with a combined 24,592,000 square feet. These properties include 57 properties with a combined 17,773,000 square feet located on the island of Oahu, HI, of which a large majority consists of land which is net leased to industrial and commercial tenants under long term ground leases. As of December 31, 2012, SIR also owned 38 single tenant, net leased suburban office and industrial properties with a combined 6,819,000 square feet located throughout the mainland United States. As of December 31, 2012, we owned 22,000,000, or approximately 56.0%, of SIR's outstanding common shares, and SIR remains one of our consolidated subsidiaries. See Note 10 for additional information regarding the SIR IPO.

As of December 31, 2012, we also owned 18.2% of the outstanding common shares of Government Properties Income Trust, or GOV, a Maryland REIT that primarily owns properties located throughout the United States that are majority leased to government tenants. GOV was our wholly owned subsidiary until its initial public offering, or the GOV IPO, in June 2009 when it became a separate public entity.