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Important Notice Regarding Changes to Payroll Withholding for Illinois State income tax

(Note: the tax withholding does not apply to Religious staff)


As you may know, on July 6, 2017, the Illinois Legislature passed an income tax increase, raising the Illinois state personal income tax rate from 3.75% to 4.95%.  The tax rate increase is effective as of July 1, 2017. Our payroll processing company, IOIPAY, has set the new rate for payrolls processed after July 14, 2017. 

Therefore, payroll checks will incorporate the new Illinois withholding rates effective immediately.

This change will result in employees having an increase in the amount of Illinois taxes withheld from their paychecks beginning with the paycheck on July 28th and thereafter.  With this change, we encourage all employees to take the opportunity to review their personal income tax elections for the year, as the change may result in additional tax liability when filing your 2017 Illinois individual tax return.

If any changes need to be made, you may complete a revised Illinois W-4 form and submit it to your local payroll contact. The form is available online at Illinois W-4 Form

The Illinois Department of Revenue (IDOR) has published a bulletin, which advises that the agency will provide additional guidance and instructions in January 2018 to address how taxpayers will calculate income tax with two different income tax rates applying to the 2017 tax year. The bulletin also addresses several other taxpayer questions regarding the tax increase. The IDOR informational bulletin is available online:

The IDOR also posted a press release this week that provides links to all the publications related to the tax increase, which is available online:

As a reminder, employees may register for IOI Payroll Employee Self-Service and have access to IOI’s secure web portal where staff can view paycheck information, pdf versions of paystubs, and past W-2’s.  Current W-4 elections can be found on the top portion of the paystub.  For more information about this self-service portal, payroll administrators should contact IOI Payroll at 1-888-607-0021.