Business

6 Months Ended

Jun. 30, 2011

Business [Abstract]

Business

1. Business

     Equity Residential (“EQR”), a Maryland real estate investment trust (“REIT”) formed in March 1993, is an S&P 500 company focused on the acquisition, development and management of high quality apartment properties in top United States growth markets. ERP Operating Limited Partnership (“ERPOP”), an Illinois limited partnership, was formed in May 1993 to conduct the multifamily residential property business of Equity Residential. EQR has elected to be taxed as a REIT. References to the “Company,” “we,” “us” or “our” mean collectively EQR, ERPOP and those entities/subsidiaries owned or controlled by EQR and/or ERPOP. References to the “Operating Partnership” mean collectively ERPOP and those entities/subsidiaries owned or controlled by ERPOP. Unless otherwise indicated, the notes to consolidated financial statements apply to both the Company and the Operating Partnership.

     EQR is the general partner of, and as of June 30, 2011 owned an approximate 95.6% ownership interest in ERPOP. All of the Company’s property ownership, development and related business operations are conducted through the Operating Partnership and EQR has no material assets or liabilities other than its investment in ERPOP. EQR issues public equity from time to time but does not have any indebtedness as all debt is incurred by the Operating Partnership. The Operating Partnership holds substantially all of the assets of the Company, including the Company’s ownership interests in its joint ventures. The Operating Partnership conducts the operations of the business and is structured as a partnership with no publicly traded equity.

     As of June 30, 2011, the Company, directly or indirectly through investments in title holding entities, owned all or a portion of 421 properties located in 16 states and the District of Columbia consisting of 120,760 apartment units. The ownership breakdown includes (table does not include various uncompleted development properties):

	Properties		Apartment Units
Wholly Owned Properties		397		111,539
Partially Owned Properties — Consolidated		22		4,371
Military Housing		2		4,850
		421		120,760