Colorado e-File – Acks and Processing

The Colorado Department of Revenue (DOR) expects to begin issuing electronic filing acknowledgments (acks) for returns on or after the dates listed below:

• Individual and Corporate returns: January 26, 2026.
• S Corporation and Partnership returns: January 30, 2026.
• Fiduciary returns: February 4, 2026.

While you will receive acknowledgments from the state, they will not begin processing e-filed returns until later. As a result:

• Acks for some returns may still be delayed or continue to show as pending during this initial period.
• Refunds will be delayed.
• Direct debit payments may be delayed.

Currently, the Colorado DOR anticipates being able to start processing all return types by mid-February 2026.