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Tax Changes Implemented Pay Period (PP) 2023-22 Locality for CO


DATE: November 2, 2023
TO: Federal Personnel and Payroll System User Group Representatives
FROM: Christine Zertuche-Rocha, Chief, Payroll Operations Division
SUBJECT: Tax Changes Implemented Pay Period (PP) 2023-22 Locality for CO

Please share this information with all impacted employees. The following tax change was implemented in PP 2023-22. As a result, employees may see a change in their tax withholdings. As a reminder, tax changes are not retroactive to employees’ withholding.

Local Tax

  • Colorado Local Income Tax Withholding:
  • City of Aurora, CO:
    • Aurora Occupational Privilege Tax (OPT) withholding has been implemented. The Aurora OPT rate is $2 per month ($0.92 for 26 PPs).
    • Datamart Query: Tax State = 08 City Code = 0110

You may execute Datamart queries to identify employees in affected state taxing areas. For Combined File Ad-Hoc query/analysis of applicable States: add STE Tax State 1 = (State Code above) or STE Tax State 2 = (State Code above) to the filter or prompt lines. See above for the applicable Local Tax State and/or Local Tax City Codes to add to the prompt lines (Occurrences – Other PE Pay). 

The Interior Business Center (IBC) Payroll website is updated frequently; you may view the state tax formulas here: Federal, State, and Territorial Income Tax Withholding Formulas.

If there are any questions, please call the IBC Customer Support Center at 1 (866) 367-1272 or by email at