Illinois employers of all sizes are now required to notify an employee when they receive notice of an identification mismatch unrelated to immigration enforcement. The requirement applies to discrepancies on tax ID numbers or other identifying documents as reported by a federal agency like the IRS or the Social Security Administration, or an outside vendor such as an insurance company. Employers can’t take adverse action against an employee solely due to receipt of the notice.

The notification to the employee needs to include that a discrepancy has been identified, the amount of time available to dispute or correct the information, and any action required by the employee. The employer should notify the employee as soon as possible, but not more than five business days after receiving the notification or determining that the employee needs to respond, whichever is later, unless federal law requires a shorter deadline.

The employer should notify the employee in person and deliver the notification by hand, if possible; otherwise, it needs to be both mailed and emailed (if the employee’s email address is known). The employer must provide the original notification upon the employee’s request. This law was passed December 12, 2025, and took effect immediately.