Key takeaways
– Form 1045 is an IRS form used by individuals, estates, and trusts to request a fast (tentative) refund based on a recent net operating loss (NOL), unused general business credit, net section 1256 contracts loss, or a claim-of-right adjustment. [IRS; Investopedia]
– A Form 1045 refund request must be filed within one year after the end of the tax year in which the triggering event (for example, the NOL year) occurred. The IRS is required to process a properly completed Form 1045 within 90 days. [IRS]
– The refund obtained via Form 1045 is “tentative”: the IRS or the taxpayer may later challenge or correct it. If you want a slower but final determination, file an amended return (Form 1040‑X for individuals or Form 1041 for estates and trusts). [Investopedia; IRS]
Who can file Form 1045
– Individuals (including sole proprietors filing as individuals), estates, and trusts may use Form 1045 to apply for a tentative refund. [IRS; Investopedia]
– The basis for filing must be one of these four things:
1. A net operating loss (NOL) carryback,
2. An unused general business credit,
3. A net loss from section 1256 contracts,
4. A claim-of-right adjustment.
(The Form 1045 instructions define exact rules and what qualifies as a loss.) [IRS]
Why choose Form 1045 vs. an amended return
– Speed: Form 1045 is intended to expedite refunds — the IRS processes it within 90 days if complete. Amended returns (Form 1040‑X or Form 1041) can take months (historically up to six months or longer). [Investopedia; IRS]
– Tentativeness: Refunds from Form 1045 are provisional and may be adjusted later. Amended returns seek a final adjustment but take longer to process. Choose Form 1045 if you prefer speed over permanence; choose an amended return if you prefer the IRS to make a final determination even if it takes longer. [Investopedia]
Important deadlines and limits
– Filing window: File Form 1045 within one year after the end of the tax year in which the NOL (or other triggering item) occurred. (Example: if the NOL occurred in tax year ending December 31, 2023, you generally must file Form 1045 by December 31, 2024.) [IRS]
– Amended returns: For comparison, amended returns (Form 1040‑X or Form 1041) generally may be filed up to three years after the original return filing date or two years after tax was paid (rules vary by situation). The IRS will not necessarily process amended returns within 90 days. [Investopedia; IRS]
– Law changes: Carryback and NOL rules have changed over recent years (e.g., CARES Act, TCJA, subsequent legislation). Always use the most recent IRS instructions or consult a tax professional to confirm whether carrybacks and tentative refunds are allowed in your situation. [IRS guidance]
How to file Form 1045 — step-by-step (practical)
1. Confirm eligibility
• Determine that your refund claim is based on an eligible ground (NOL, unused credit, section 1256 loss, or claim-of-right). Review the current IRS Instructions for Form 1045 to verify qualification and any statutory changes to carryback rules. [IRS]
2. Determine the carryback year(s) and calculate the tax decrease
• Compute the amount of the NOL or credit you will carry back and how it reduces taxable income in earlier year(s).
• Figure the decrease in tax for each carryback year. You must compute the tax benefit that results from applying the carryback to tax years before the loss or credit year. (Follow the worksheet and rules in the Form 1045 instructions.) [IRS]
3. Gather required documentation and attachments
• Attach copies of specific pages/forms requested in the instructions. Typically required attachments include:
• The first two pages of Form 1040 (individual filers),
• Form 4952 (Investment Interest Expense Deduction), if applicable,
• All Schedules K-1 (from partnerships, S corporations, estates, or trusts) showing items used in the NOL or credit computation,
• Any other supporting worksheets or statements required by the Form 1045 instructions.
• Do NOT attach Form 1045 to the original tax return; file it separately (usually in a separate envelope). [IRS; Investopedia]
4. Complete Form 1045 carefully
• Provide taxpayer identification, name, address, and tax year information.
• Answer the questions about the nature of the carryback and compute the decrease in tax for each year prior to the loss/credit year per the form lines and instructions.
• Sign and date the form. If a paid preparer completes it, the preparer must also sign and provide their PTIN. [IRS]
5. Where and how to file
• Historically, Form 1045 is filed by mail to the IRS address specified in the Form 1045 instructions (addresses can vary by taxpayer location and whether a payment is enclosed). Check the latest Form 1045 instructions for the correct mailing address or for any updated electronic filing options. [IRS]
6. Keep copies and monitor for IRS response
• Keep a complete copy of Form 1045 and all attachments.
• The IRS aims to process a properly completed Form 1045 within 90 days and will issue a tentative refund if the claim is allowed. Because the refund is tentative, the IRS may later examine and adjust it; retain records to support your computations. [IRS; Investopedia]
7. If the IRS disagrees or if you want a final determination
• If the IRS adjusts or disallows your tentative refund, you may need to respond to inquiries or file an amended return (Form 1040‑X or Form 1041) for a final resolution. Consult a tax professional when disputes arise. [Investopedia]
Practical checklist before you mail Form 1045
– Confirm you meet the one-year filing deadline (one year after the end of the loss/credit year).
– Completed and signed Form 1045.
– Attach first two pages of Form 1040 (individual), Form 4952 (if applicable), and all Schedules K‑1.
– Include worksheets and computations showing the NOL/credit calculation and tax decrease per carryback year.
– Make and retain complete photocopies.
– Mail to the IRS address listed in the Form 1045 instructions (or follow updated filing guidance if the IRS has changed filing procedures).
Common pitfalls and tips
– Filing late: Missing the one-year window for a Form 1045 claim will disqualify you from the tentative-refund procedure (though you may still seek relief via an amended return, subject to longer limitations).
– Incomplete attachments: Omitting required schedules or K‑1s will delay processing or trigger denial.
– Mistaken permanence: Remember that Form 1045 refunds are temporary and subject to later audit or adjustment.
– Check current law: NOL carryback rules have changed recently in U.S. tax law; confirm whether carrybacks are allowed for your tax year and situation before filing. If you are unsure, consult a tax professional. [IRS]
Other relevant forms
– Form 1040‑X — Amended U.S. Individual Income Tax Return (for individuals who prefer a final corrected refund rather than a tentative one). [Investopedia]
– Form 1041 — U.S. Income Tax Return for Estates and Trusts (useful when tax adjustments involve estates/trusts; Form 1045 may be an alternative for tentative refunds). [Investopedia]
– Form 4952 — Investment Interest Expense Deduction (attach if it affects your NOL/credits). [IRS]
– Schedules K‑1 — Partnership/S-corporation/trust beneficiary statements (attach copies used in the NOL/credit computation). [IRS]
When to consult a tax professional
– Complex NOL computations, multi-year carrybacks, partnership S‑corp interactions, or claim-of-right adjustments often require professional help. A tax advisor can help ensure you choose the best filing approach (Form 1045 vs. amended return), prepare accurate computations, and respond to IRS examinations.
Primary sources and further reading
– IRS, Instructions for Form 1045, Application for Tentative Refund (see specific filing addresses and worksheets). [IRS]
– IRS, About Form 1045, Application for Tentative Refund. [IRS]
– IRS, Guidance on changes to excess business losses and net operating losses (background on legislative changes). [IRS]
– Investopedia, “Form 1045: Application for Tentative Refund” (overview and practical comparisons with Form 1040‑X/Form 1041). [Investopedia]
(When preparing Form 1045, always use the most recent IRS instructions and consider professional tax advice—tax law and procedural rules can change.)
(Continuation)
Required attachments and information — what to include
– A completed Form 1045, signed and dated by the taxpayer (or fiduciary for an estate or trust). If a paid preparer signs, include preparer information and signature.
– Copies of the first two pages of the income tax return for the year to which you’re carrying back the loss (for individuals, the first two pages of Form 1040).
– Copies of any Forms 4952 (Investment Interest Expense Deduction) that affect the carryback computation.
– All Schedules K-1 that reflect items carried back (for partnerships, S corporations, estates/trusts).
– A computation showing how the tentative refund was calculated (year-by-year carryback calculations and supporting schedules).
– Any statements, elections, or supporting documents referenced on Form 1045 (for example, a claim-of-right adjustment explanation).
– A power of attorney (Form 2848) if an authorized representative will receive the refund.
Filing deadlines, processing time, and limitations
– Deadline to file Form 1045: generally within one year after the end of the taxable year in which the NOL, unused credit, net section 1256 contracts loss, or claim-of-right adjustment arose. (See IRS Instructions for Form 1045.)
– IRS processing requirement: the IRS is required to process the Form 1045 application within 90 days of receipt (hence the name “tentative refund” — the agency gives a fast refund, subject to later review).
– Contrast with amended returns: Form 1040-X (individuals) and Form 1041 (estates/trusts) can often be filed to obtain refunds for up to three years after the return was filed (or two years after tax was paid), but the IRS may take longer (up to six months or more) to process those refunds.
– Limitations: some NOLs arising in recent law-change years (for example, rules after the 2017 tax law, or special provisions enacted by the CARES Act for certain years) affect whether a carryback is allowed and for which years. Always check current IRS guidance.
When to use Form 1045 vs. Form 1040-X or Form 1041
– Use Form 1045 when you want a fast, provisional refund based on a carryback of:
• Net operating loss (NOL),
• Unused general business credit,
• Net section 1256 contracts loss,
• Claim-of-right adjustments.
– Advantages of Form 1045:
• Faster processing (IRS generally processes within 90 days).
• Useful when taxpayer needs liquidity quickly.
– Disadvantages:
• Refund is tentative — the IRS can later adjust or disallow it after review.
• You must file within one year after the end of the year the act creating the carryback occurred — a shorter window than some amended return deadlines.
– Use Form 1040-X or Form 1041 when:
• You prefer a final, audited adjustment and don’t need a fast refund.
• You are outside the one-year filing window for Form 1045 but still within the time limits for amended returns.
• You do not have an NOL or qualifying event that fits Form 1045’s categories.
Step-by-step practical filing guide
1. Determine eligibility
• Confirm that your situation involves an NOL, unused general business credit, net section 1256 contracts loss, or a qualifying claim-of-right adjustment.
• Verify the NOL/credit/year qualifies for a carryback under current tax law for the year in question.
2. Compute tentative carryback refund
• For each carryback year, compute the taxable income as adjusted by carrying back the loss or credit; determine the tax decrease for those years.
• Apply any applicable credits, tax rate changes, or limits that affect the carryback amount.
3. Gather documentation
• Copies of the tax return pages and supporting forms/schedules listed above.
• Detailed computations and worksheets to justify the carryback.
4. Complete Form 1045
• Provide taxpayer identification, address, qualifying event information, and a calculation of the tentative refund.
• Sign and date the form.
5. Mail the application
• File Form 1045 separately (it is not attached to the income tax return) to the appropriate IRS address provided in the Form 1045 instructions. Keep copies for your records.
6. Track processing and follow up
• Expect IRS processing within about 90 days. The IRS may send a tentative refund check or a notice explaining the adjustment.
• If the IRS disallows or adjusts after review, you may be required to repay amounts plus interest or receive additional refund, depending on the outcome.
7. If you prefer not to receive a tentative refund
• If you want a final audited refund and to avoid later adjustments, file an amended return (Form 1040-X or Form 1041) instead and accept the longer processing time.
Examples (illustrative)
Example 1 — Simple NOL carryback for an individual (illustrative numbers)
– Tax year 2022: Taxpayer has a net operating loss of $40,000 arising in 2022.
– Tax year 2019: Taxable income before carryback was $25,000; tax liability for 2019 was $3,000.
– Carryback result: Carry $25,000 of the NOL back to 2019, reducing 2019 taxable income to $0 and reducing tax by $3,000.
– Tentative refund: Taxpayer files Form 1045 within one year after 2022 ends, includes 2019 Form 1040 pages, and requests a $3,000 tentative refund. The IRS processes within 90 days and issues the refund provisionally.
– Note: If the IRS later audits the 2022 NOL calculation and adjusts it, the tentative refund could be increased or decreased, possibly subject to interest.
Example 2 — Unused general business credit carryback for a trust
– A trust has an unused general business credit in 2023 of $5,000 that may be carried back to 2021.
– The trustee files Form 1045 to apply the $5,000 credit to 2021. Copies of the relevant Form 1041 schedules and K-1s are attached.
– The trustee receives a tentative refund or credit offset within about 90 days while the IRS reviews the claim.
Example 3 — Claim-of-right adjustment
– Taxpayer included $10,000 in income in 2020 under a claim-of-right that was later repaid in 2022.
– The taxpayer may be able to file Form 1045 to carry back an adjustment to 2020 and obtain a tentative refund for tax attributable to the repayment, if within the one-year window and otherwise eligible.
Common issues and pitfalls
– Missing the one-year filing deadline for Form 1045: if you file after the one-year deadline, you may still be eligible to claim the refund via an amended return (Form 1040-X or Form 1041), but it will take longer to process.
– Not including required attachments: failing to include the return pages or schedules can delay processing or cause denial.
– Changes in tax law: NOL rules and carryback eligibility have changed in recent years (for example, the Tax Cuts and Jobs Act and CARES Act made and then modified carryback rules for certain years). Verify current rules for the specific tax year involved.
– Offsets: tentative refunds may be offset to pay past-due federal or state debts, child support, or other government obligations.
– Interest: depending on timing and audit results, interest may be due if the amount must be repaid; conversely, interest may be paid if refund is delayed.
If the IRS disagrees or makes adjustments
– The IRS can later audit and adjust a tentative refund. If the IRS determines the claim was incorrect, it can assess tax and interest; the taxpayer will receive a notice describing the adjustment.
– Taxpayer rights: you can protest the disallowance and seek administrative appeal or, ultimately, judicial review if necessary. Consider consulting a tax professional or attorney for complex disputes.
When to consult a tax professional
– Complex carryback computations (multiple years, different tax rate regimes, AMT or other special taxes).
– Large NOL amounts or when multiple entities (partnerships, S corporations) are involved and K-1s and basis calculations are required.
– If a tentative refund might be offset against other liabilities or if a repayment risk is high.
– For representation in case of an IRS audit or dispute.
Other relevant forms and references
– Form 1045, Application for Tentative Refund (instructions): for details on completing and mailing the form.
– Form 1040-X, Amended U.S. Individual Income Tax Return: if you prefer a final amended return instead of a tentative refund.
– Form 1041, U.S. Income Tax Return for Estates and Trusts: for estates and trusts filing amended returns.
– Form 1139, Corporation Application for Tentative Refund (if you’re a corporation).
– Form 2848, Power of Attorney and Declaration of Representative: to allow a representative to file and receive a refund.
Sources
– Internal Revenue Service. Instructions for Form 1045. Accessed Aug. 11, 2021. (See IRS.gov for current instructions.)
– Internal Revenue Service. About Form 1045, Application for Tentative Refund. Accessed Aug. 11, 2021.
– Investopedia. “Form 1045.” Accessed [source provided].
Concluding summary
Form 1045 provides a way for individuals, estates, and trusts to request a quick, tentative refund when a qualifying event—such as a net operating loss or unused general business credit—allows a carryback to earlier tax years. The main benefits are speed (IRS processing within about 90 days) and faster access to cash. The key trade-offs are that the refund is tentative (subject to later audit and adjustment) and the filing window is relatively short (generally within one year after the end of the year in which the loss or credit arose). Use Form 1045 when you need a quick refund and are comfortable with the possibility of later adjustments; use amended returns (Form 1040-X or Form 1041) if you prefer a final determination at the cost of slower processing. Because tax-law details and carryback eligibility can change, and because carryback computations can be complex, consider getting professional tax help for large or complicated claims.