Business

12 Months Ended

Dec. 31, 2010

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. EQR has elected to be taxed as a REIT.

EQR is the general partner of, and as of December 31, 2010 owned an approximate 95.5% ownership interest in, ERP Operating Limited Partnership, an Illinois limited partnership (the “Operating Partnership”). The Company is structured as an umbrella partnership REIT (“UPREIT”) under which all property ownership and related business operations are conducted through the Operating Partnership and its subsidiaries. References to the “Company” include EQR, the Operating Partnership and those entities owned or controlled by the Operating Partnership and/or EQR.

As of December 31, 2010, the Company, directly or indirectly through investments in title holding entities, owned all or a portion of 451 properties located in 17 states and the District of Columbia consisting of 129,604 apartment units. The ownership breakdown includes (table does not include various uncompleted development properties):

	Properties		Apartment Units
Wholly Owned Properties		425		119,634
Partially Owned Properties – Consolidated		24		5,232
Military Housing		2		4,738
		451		129,604

The “Wholly Owned Properties” are accounted for under the consolidation method of accounting. The Company beneficially owns 100% fee simple title to 422 of the 425 Wholly Owned Properties and all but one of its wholly owned development properties and land parcels. The Company owns the building and improvements and leases the land underlying the improvements under long-term ground leases that expire in 2026, 2077 and 2101 for the three operating properties, respectively, and 2104 for one land parcel. These properties are consolidated and reflected as real estate assets while the ground leases are accounted for as operating leases.

The “Partially Owned Properties – Consolidated” are controlled by the Company but have partners with noncontrolling interests and are accounted for under the consolidation method of accounting. The “Military Housing” properties consist of investments in limited liability companies that, as a result of the terms of the operating agreements, are accounted for as management contract rights with all fees recognized as fee and asset management revenue.