Assessor’s Office Defends Higher Data Center Assessments at Appeal Hearings

Several data centers and other large commercial properties in Cook County saw only minor reductions in value after the Cook County Assessor’s Office defended its assessments during the 2025 appeals cycle at the Cook County Board of Review. 

These successes will help preserve the property tax base in the northwest suburbs, preventing the tax burden from being shifted onto homeowners. 

“We’ve poured a lot of resources into building out a team that can make sure big commercial properties are assessed fairly,” said Cook County Assessor Fritz Kaegi. “That’s going to help keep tax bills manageable for homeowners struggling with affordability right now.” 

The Assessor’s Office hears appeals of its assessments, but most commercial properties in Cook County also appeal to the Board of Review, a separate elected body. 

Over the past year, Assessor Kaegi has hired staff and created a new team to appear at Board of Review appeal hearings to defend the office’s assessments of commercial property. 

This initiative is part of the office’s implementation of the Cook County Roadmap, a set of recommendations from a 2024 study of commercial valuations put out by the county’s Property Tax Reform Group. 

That study found commercial properties were typically assessed below their market value after appeals. Higher-value commercial properties were especially prone to underassessment. 

For the 2025 reassessment, the CCAO targeted 14 large commercial properties for appeal hearings at the Board of Review. Almost all of them are large data centers built in northwest suburban municipalities within Elk Grove and Leyden townships. Two other properties included an industrial park and an oil tank farm. 

In most cases, a successful result

Of the 14 properties targeted by the Assessor’s Office, four did not receive any reduction at all from the Board of Review. 

These properties kept their original assessment from the Assessor’s Office: 

• T5 Chicago II Data Center in Elk Grove Village, $106 million market value 
  
   
• Skybox Chicago 1 Data Center in Elk Grove Village, $102 million market value
  
   
• EdgeConnex CHI 01 Data Center in Elk Grove Village, $70 million market value
  
   
• Bridge Point Industrial Park in Melrose Park, $20.5 million market value

The property owners requested assessment reductions for these properties that ranged from 24% to 90%. 

Another four properties received reductions in their assessments of less than 25%. In these cases, the Board of Review generally agreed with the CCAO’s analysis that found land rates in this part of the north suburbs has increased in recent years. 

Preserving the property tax base

These decisions will help preserve the property tax base in Elk Grove and Leyden. That can protect homeowners and small commercial property owners from property tax increases due to burden-shifting. This kind of burden-shifting contributed to larger tax bills in some parts of the north suburbs after the last reassessment in 2022.  

In Elk Grove Township, the 2022 reassessment saw homeowners’ share of the property tax burden jolt upward by 4 percentage points, from 38% to 42%. That was partly due to large reductions during appeal for commercial properties. 

That could have contributed to significant property tax spikes for residents: In recent years, nearly 7,000 homeowners in Elk Grove Township have seen their bills increase by 25% or more. For the typical homeowner, that increase was over $1,800. 

For some neighborhoods of the township in Elk Grove Village, nearly half of homeowners saw that level of tax spike. 

In the 2025 reassessment of Elk Grove Township, by contrast, homeowners maintained their share of the property tax base at 41% after appeals concluded at the Board of Review. While property tax bills that reflect this reassessment will not be out until later in 2026, that could mean fewer homeowners end up with spiking tax bills. 

Three properties enter settlement agreements

In some instances, property owners enter into settlement agreements with local taxing districts. These settlement agreements fix the assessment of the property at a given value, often for several years. 

The Board of Review must accept the settlement agreement for it to go into effect, but neither it nor the Assessor’s Office are part of the settlement negotiations. 

For three of the 14 properties that the CCAO targeted, the property owners entered into settlement agreements with local school districts that led to large assessment reductions. 

These were all Digital Realty data center properties located in Franklin Park and Northlake: 

• Digital Realty ORD-15 Data Center, 28.94% reduction in assessment
  
   
• Digital Realty ORD-12/ORD-13 and ORD-14 Data Centers, 33.91% reduction in assessment
  
   
• Digital Realty ORD-23 Data Center, 67.75% reduction in assessment 

Continued concerns about commercial appraisal quality 

The Assessor’s Office was only able to participate in a small fraction of the appeals filed in front of the Board of Review each year. These appeals rely on appraisals that may systematically underestimate the market value of commercial property. 

In January 2025, the Assessor’s Office published an analysis of 60 appraisals submitted as part of appeals with our office. It found that these appraisals underestimated the market value of properties by 38%. 

“Our staff have done great work to defend our assessments during the appeals process,” said Assessor Kaegi. “But we know that there are thousands of other cases filed each year that we can’t appear at. We need oversight and regulation to make sure that the appraisals put in front of the Board of Review pass muster. Otherwise it’s going to continue to be felt by the rest of Cook County’s property owners.”