Aimco or Apartment Investment Management Company is a publicly traded real estate investment trust.

As of December 31, 2016, the company owned 46,311 apartment units, including 32,433 conventional apartment units in Atlanta, the San Francisco Bay Area, Boston, Chicago, Denver, the Washington metropolitan area, Los Angeles, Miami, New York City, Philadelphia, San Diego, and Seattle, 5,489 apartment units in other non-core markets, and 8,389 units of affordable housing.

Aimco traces its roots to The Considine Company, formed in 1975 by Terry Considine.

Aimco was incorporated on January 10, 1994.

On July 29, 1994, the company became a public company via an initial public offering.

In 1994, Aimco acquired Homecorp, a management company with 5,300 units based in Montgomery, Alabama.

In 1996, Aimco acquired Walters Management Company and the J.W. English Company.

Aimco also acquired a portion of the general partnership of Balcor Asset Management resulting in the addition of 67 properties in three states.

In 1997, Aimco acquired National Housing Partnership Incorporated, which owned 87,659 apartments.

In October 1997, Aimco acquired 8,175 apartment units from Winthrop.

In 1998, Aimco acquired Insignia Financial Group in a $910 million transaction.

In 2000, the company acquired Oxford Realty Financial Group, which owned interests in 36,662 apartment units, for $314 million. Also in 2000, the company acquired the Oxford Tax-Exempt Fund for $206 million.

In 2002, Aimco acquired Casden Properties, founded by Alan Casden. The $1.5 billion acquisition included 17,383 apartments, including 6,356 conventional apartment units located in Southern California and 11,027 affordable apartment units in 25 states.

In 2003, the company was added to the S&P 500 Index.

In February 2017, the company acquired Indigo Apartments in Redwood City, California for $320 million.

In July 2017, the company acquired the 47% interest it did not own in 3 properties for $451 million, based on a valuation of $695,107 per apartment unit.