42-029: IA 101 Nonconformity Adjustments 42-029 (2025)
Iowa · Iowa DOR · Used for tax years 2025
Iowa Form IA 101 reports adjustments to Iowa net income resulting from differences between Iowa and federal tax law in 2018 and 2019. It also tracks accumulated adjustments from Iowa’s 2018 nonconformity, including amounts remaining for future years.
Who files this form
Include IA 101 with your Iowa tax return if you enter any adjustment on Part I, lines 1–12.
This form reports carryforward and other adjustments resulting from Iowa’s 2018 and 2019 differences from federal tax law. It may be used by taxpayers filing IA 1040, IA 1041, IA 1065, IA 1120, IA 1120S, or IA 1120F. Not every adjustment applies to every taxpayer or return type.
Do not use this form to report carryover adjustments from 2018 if you did not file an Iowa return for 2018.
What you'll need
Have the records that apply to your adjustments available:
- Your 2018 Iowa Nonconformity Adjustments Worksheet and relevant 2018 Iowa return entries.
- Prior-year IA 101 forms, including Part II, to track adjustments already claimed and amounts remaining.
- Records supporting the current-year adjustment, such as federal income or deduction amounts and property disposition information.
- The IA 8824 Worksheet if you have a like-kind exchange adjustment. Line 2 uses the gain or loss adjustment from that worksheet’s line 25.
- A supporting schedule explaining any amounts entered on line 12. Attach this schedule.
Keep a copy of IA 101 and supporting documentation for as long as the adjustments apply. Part II information is needed to complete the form in future years.
How to file
Include the completed IA 101 with your Iowa tax return. The supplied text does not give a mailing address or e-file instructions.
- Enter your name, tax period end date, and SSN or FEIN.
- Complete the applicable Part I adjustments using dollars and cents. Amounts may be positive or negative.
- Add lines 1–12 and enter the total on line 13.
- Transfer line 13 to the appropriate place on your Iowa return.
- Complete Part II as applicable to track remaining adjustments from Iowa’s 2018 nonconformity. Attach a supporting schedule for any line 12 adjustments.
For tax year 2025, the printed transfer instructions direct you to:
- IA 1040: Schedule 1, line 11, code x. Use column A for positive amounts and column B for negative amounts.
- IA 1041: Schedule A, Part I, line 4 for positive amounts; Schedule A, Part II, line 6 for negative amounts.
- IA 1065 or IA 1120S: Schedule A, line 12.
- IA 1120: Schedule A, line 15.
- IA 1120F: Schedule A, line 9.
Common mistakes
- Using lines that no longer allow adjustments. For tax year 2025, no adjustment is allowed on lines 3 or 4, and no deduction is allowed on line 6.
- Putting depreciation differences on IA 101. Iowa and federal differences in depreciation and section 179 expensing belong on IA 4562A and B, not this form.
- Entering negative amounts in Part II. All Part II entries must be positive amounts, even when the corresponding Part I adjustment is negative.
- Including line 3a amounts in Part II. Part II tracks 2018 nonconformity carryforwards, not the 2019 CARES Act interest expense adjustment entered on line 3a.
- Overstating remaining carryforwards. Part II, column B cannot exceed column A. Column D equals A minus B minus C and cannot be negative.
- Leaving out the explanation for line 12. Attach a supporting schedule explaining the adjustment amounts.
Questions people ask
Why might I need this form after 2018 or 2019?
Differences between Iowa and federal tax law in those years can require adjustments to Iowa income in later years. IA 101 reports those carryforward and other adjustments.
Can an adjustment be negative?
Yes. Part I amounts may be positive or negative. In Part II, however, enter all amounts as positive numbers, even if the Part I adjustment was a deduction.
What does Part II track?
Part II tracks accumulated adjustments from Iowa’s 2018 nonconformity. It shows the original adjustment, amounts claimed in prior years, the current-year adjustment, and the amount remaining for future years.
Can individuals report charitable contribution carryforward adjustments on line 4?
No. Individuals are instructed to enter zero on line 4 and account for those adjustments on IA 1040, Schedule A. The instructions also state that no adjustment is allowed on line 4 for tax year 2024 or later.