66: Fiduciary Income Tax Return and Instructions 2024 (2024)
Idaho · Idaho Tax Commission · Used for tax years 2024
Idaho Form 66 is the 2024 Fiduciary Income Tax Return for estates and trusts. It reports Idaho income, deductions, credits, tax, and payments to determine the amount due or overpayment. It can be used for an original or amended return.
What you'll need
Include these with your Idaho Form 66:
- A complete copy of federal Form 1041, including all federal Schedule K-1s.
- All Idaho Forms ID K-1. The trust or estate must also provide each beneficiary with an Idaho Form ID K-1.
Depending on what you report, also include:
- Nonresident beneficiaries: Form PTE-12 if you answer “Yes” to question 2. Also include it if the trust or estate files as a pass-through entity.
- Idaho withholding: State copies of Forms W-2 or 1099.
- Payments under other EINs: A schedule listing the EINs, payment amounts, and refunds carried forward.
- Credit for tax paid to another state: A copy of that state's return and a separate Schedule B for each state.
- Business credits or credit recapture: Form 44, as applicable.
- Fuels use tax or fuel tax refunds: Form 75.
- Qualified investment exemption recapture: Form 49ER.
- Tax reimbursement incentive credit: A copy of the Idaho Reimbursement Incentive certificate.
- Net operating losses: Form 56 or a schedule showing how the loss is applied.
- Income adjustments: The explanations and schedules required for the amounts you report on Schedule A.
An Electing Small Business Trust (ESBT) return also needs the complete federal Form 1041 ESBT tax calculation worksheet, appropriate schedules, and the Idaho ESBT tax calculation worksheet. A composite Qualified Funeral Trust (QFT) return needs a separate schedule calculating each QFT's Idaho taxable income and tax liability.
How to file
Use the 2024 return for calendar year 2024 or a fiscal year beginning in 2024. For a fiscal year, enter the beginning and ending dates at the top of the form.
Enter the trust or estate's name, the fiduciary's name and title, mailing address, and federal EIN. Complete the applicable boxes, questions, calculations, and schedules. The fiduciary or an officer representing the fiduciary must sign the return.
Mail a return with payment to:
Idaho State Tax Commission
PO Box 83784
Boise ID 83707-3784
Mail a return without payment to:
Idaho State Tax Commission
PO Box 56
Boise, ID 83756-0056
Include the required attachments. Do not staple the return.
Common mistakes
- Leaving required questions unanswered. Answer questions 2 and 3, and complete questions 1a through 1d when filing for an estate. Incomplete returns delay processing.
- Including the dash in the EIN. Enter the EIN without the dash.
- Not rounding amounts. Round to the nearest whole dollar: down for amounts under 50 cents and up for 50 cents or more.
- Claiming another-state tax credit as a nonresident. Nonresident trusts and estates cannot claim this credit.
- Including state income taxes in Schedule A deductions. Do not include state income taxes deducted on federal Form 1041, line 11, in Schedule A, line 16.
- Putting ESBT or QFT items on Schedule A. The line 22 instructions say not to include these items there.
- Treating a scholarship donation as reversible. A donation to the Idaho Opportunity Scholarship Program reduces your refund or increases your tax due. You cannot change the choice or get the donation refunded later.
Questions people ask
Can I use Form 66 to amend a return?
Yes. Check the amended return box and enter the reason number: 1 for a federal audit, 2 for a net operating loss carryback, 3 for a federal amended return, or 4 for another reason. For reason 2, include Form 56 or a schedule showing how the loss is applied. For reason 4, include an explanation. Complete the entire form with corrected amounts.
What information must beneficiaries receive?
Each beneficiary must receive an Idaho Form ID K-1 showing their share of Idaho additions, subtractions, and credit information. It also identifies their share of gross income to help determine their Idaho filing requirements.
Can I apply an overpayment to next year's tax?
Yes. On an original 2024 return, enter the amount you want refunded on line 35. The remaining overpayment is applied to your 2025 tax and will not be refunded. Refunds of less than $1 are not issued.
Does a Qualified Funeral Trust owe the permanent building fund tax?
No. The instructions say to enter zero on line 17 for a QFT.