September 20, 2017
(CHICAGO) The full market value of real estate in Cook County was approximately $528.8 billion in tax assessment year 2015 according to an annual estimate released today by the Civic Federation. The 2015 total value estimate represents an increase of $29.7 billion, or 6.0%, from the 2014 estimated full value. Tax year 2015 is the most recent year for which data are available. The 2015 estimates represent the third time since 2006 that real estate values in Cook County increased.
“Following several years of decline, this third consecutive year of growth in the estimated full value of property in Cook County is a positive sign that the real estate market continues to recover,” said Civic Federation President Laurence Msall. Prior to 2007, the estimated full value of real estate in the City of Chicago and suburbs grew every year going back to at least 1995.
In addition to Cook County as a whole, the report estimates the full market value of real estate in the City of Chicago, northwest Cook County suburbs and southwest Cook County suburbs. The estimated full market value of real estate in the City of Chicago increased by 8.8% in tax assessment year 2015 while the northwest and southwest suburbs experienced increases of 2.4% and 4.1%, respectively.
The estimated full value of all major classes of property in every assessment district fell between 2006 and 2015. Between 2006—the peak estimated value—and 2015 the estimated full value of all classes of property in Cook County as a whole declined by 20.6%. As shown in the chart below, estimated full value decreased from a high of $666.2 billion in 2006 to a low of $414.4 billion in 2012, a decline of 37.8%, and then rising in 2015 to $528.8 billion.
The full market value estimates in this report are based on two data sources: the total assessed value of property as reported by the Cook County Assessor’s Office and the median level of assessment reported by the Illinois Department of Revenue. The Illinois Department of Revenue collects data on property sales and calculates the ratio of assessed values to sales values. That data is used to compute the mean assessment-to-sales ratio, or the median level of assessment.
The Civic Federation estimates the full value of property by dividing the median level of,assessment into the total assessed value of each class of property in Cook County. For those classes for which the Department of Revenue does not calculate a median level of assessment, the level set by County ordinance is used.
 Report updated in March 2018 per IDOR revisions to 2015 Assessment-Sales Ratio Study