Cook County Second Installment Tax Bills’ due date to be delayed by at least one month

Earlier this week, the Chicago Tribune reported that due to technological issues at the Cook County Assessor’s Office, second installment tax bills in Cook County will be delayed by at least one month from their usual August due dates, as has occurred in the past two tax years. This delay from the expected August 1, 2025 due date will cause the bills to be due later in the fall which could be uncomfortably close to the holiday shopping season.

Cook County Assessor Fritz Kaegi’s Office is blaming Tyler Technologies, the contractor in charge of updating the Assessor’s data systems, for the delay in the second installment tax bills.  Other property tax officials argue that Assessor Kaegi failed to prioritize this issue and missed key foundational steps in the process.  Although his office finished its first round of assessments in December, 2024, it did not send that first batch of data to the Illinois Department of Revenue (IDOR) until April 30, 2025, which was three months later than in 2024.

Tyler Technologies was originally asked by the Assessor’s Office to develop their reports for IDOR last year, but the company missed deadlines in both November, 2024 and January, 2025.

The Assessor changed its IDOR report to “High” priority on its lists of projects with Tyler on January 30, 2025, after which it met with the company at least once one a week to receive progress updates.  By February 2025, test versions of the report were ready but riddled with technical issues. According to spokesperson, Christian Belanger, this forced the Assessor’s office to “create workarounds … rewrite the process for generating report data almost entirely from scratch” and put the reports together manually.  The final report was mailed to IDOR on May 12, 2025.

This report is critical for IDOR to issue both a tentative Cook County Equalization Factor and then a final Cook County Equalization Factor, used to calculate the tax bills.  In 2024, the tentative equalization factor was issued on February 8, 2024 and the final Cook County Equalization Factor on May 20, 2024.  An IDOR representative confirmed that it would not be possible to issue both the tentative and final reports simultaneously.  This marks the first year the IDOR report was generated on the Assessor’s new mainframe system, which Kaegi has repeatedly and publicly promoted as “state of the art” and not on the county’s old mainframe system.