Property Tax Extension Limitation Law (PTELL)

• Section 18-185 of the Property Tax Code define CPI as "the Consumer Price Index for All Urban Consumers for all items published by the United State Department of Labor." This index is sometimes referred to as CPI-U. Section 18-185 defines "extension limitation" as ... "the lesser of 5% or the percentage increase in the Consumer Price Index during the 12-month calendar year preceding the levy year..." (emphasis added).
• For 2009 extensions (taxes payable in 2010), the CPI to be used for computing the extension limitation is .1%. The CPI is measured from December 2007 to Decemeber 2008. The U.S. City Average CPI for December 2007 was 210.036 and 210.228 for December 2008. The CPI change is calculated by subtracting the 2007 CPI of 210.036 from the 2008 CPI of 210.228. That amount , .0192, is divided by the 2007 CPI of 210.036, which results in 0.09%, which is rounded to a 0.1% CPI.

Property Tax Extension Limitation Law Booklet