“Mega‑Projects” The Illinois Bill, What It Means for Communities Across the State

GraniteCityGossip.com February 26, 2026

Illinois lawmakers advanced a controversial “mega‑projects” bill this week, a proposal designed to help secure a new Chicago Bears stadium but written broadly enough to benefit any massive development across the state. The bill would allow qualifying projects like stadiums, data centers, industrial complexes, and other developments over roughly $500 million, to lock in their property tax assessment at the base‑year value for 20 years, with the option to negotiate extensions up to 40 years.

Under the proposal, once a project is certified as a “mega‑project,” any new value added to the property such as new buildings, expansions, equipment, or improvements, cannot be taxed during the incentive period. The property’s taxable value stays frozen at what it was before construction began.

Developers would also be allowed to negotiate special payment deals with local governments, paying a fixed amount instead of rising property taxes.

Data centers and industrial parks are a major part of this story because the bill applies to any qualifying mega‑project, and not just the Bears. Large data centers and industrial facilities would be eligible for the same long‑term tax freeze.

That means:
A $500M+ data center could avoid higher assessments for 20–40 years. Local governments would be unable to tax the increased value of the facility as it grows.

The share of the tax base shifts away from the largest, most resource‑intensive developments.

This is why critics warn the bill could accelerate the spread of data centers and industrial parks statewide, especially in communities already targeted for large‑scale development.

Legislators and watchdog groups warn of the possible impact on homeowners and small businesses testifying that the bill could lead to a “meteoric rise” in property taxes for residents and small businesses.

The concern is straightforward:

Mega‑projects get decades of tax protection.
Their share of the tax base shrinks over time.
Local governments still need revenue.
Homeowners and small businesses make up the difference.
No carve‑outs were added to exclude data centers or industrial complexes, despite warnings from multiple lawmakers.

The bill freezes the entire property’s taxable value at whatever it was before the mega‑project began. Any new construction, expansions, or improvements are legally ignored for tax purposes for 20 years — and potentially up to 40 years if negotiated.

What this means in practice:

A developer builds a $600M data center the base‑year value is locked in.
Five years later, they add two more buildings, doubling or tripling the footprint.
All of that new value is excluded from taxation.
The county assessor must continue taxing the property as if only the original build exists.

If a data center adds on‑site energy generation, those new facilities also remain untaxed and the same clause applies to any improvements, including:

On‑site substations.
Battery storage.
Natural gas turbines.
Solar arrays.
Cooling towers.
Additional server halls.
New utility buildings.

Because these are “value added to the property,” they are excluded from assessment for the entire incentive period.

This is not an interpretation, it is explicitly stated in the bill text:

“The value added to the property by the project shall not be considered for assessment purposes.”

The bill passed out of committee but still requires approval from the full House, the Senate, and the Governor before becoming law. Lawmakers adjourned without taking a floor vote, and the next opportunity comes when they reconvene in mid‑March.