1065 K-1 Instructions: Boxes, Loss Limits, and Deadlines

The Schedule K-1 for Form 1065 reports your share of a partnership’s income, deductions, and credits for the year, and its numbers flow directly onto your personal Form 1040. The partnership itself doesn’t pay federal income tax. It files Form 1065 as an information return, and each partner receives a K-1 showing exactly what to report.¹ Reading the form correctly means knowing what each box captures, where it goes on your return, and which limitations decide whether you can actually use the losses shown.

Parts I and II: Who the Partnership Is and Who You Are

Part I identifies the partnership by Employer Identification Number, legal name, and address. Mismatches with IRS records trigger automated notices, so this information needs to match the partnership’s other filings exactly.²

Part II identifies you: your Social Security Number or TIN, your address, and your role in the partnership. That last piece matters more than it looks. The form asks whether you are a general partner, a limited partner, an LLC member-manager, or another LLC member.³ General partners and LLC member-managers generally owe self-employment tax on their share of ordinary business income. Limited partners generally do not. A wrong classification here changes what you owe.

Profit, Loss, and Capital Percentages

The K-1 shows your beginning and ending percentages for profit, loss, and capital.³ Those percentages come from the partnership agreement and drive nearly every allocation on the form. If you bought in, sold part of your interest, or added capital during the year, the beginning and ending figures should differ. A wrong percentage here multiplies through every income and deduction line, so compare them against any ownership changes documented during the year.

Part III: The Income and Deduction Boxes

Part III is where the dollars appear. Each box holds a different category of item because each category is taxed differently on your personal return.

Box 1: Ordinary Business Income

Box 1 shows your share of the partnership’s net profit or loss from its core trade or business, after operating expenses. It excludes rental income, investment gains, and guaranteed payments, which have their own boxes. If you’re a general partner or LLC member-manager who materially participates, this amount is subject to self-employment tax on top of ordinary income tax.²

Box 2: Rental Real Estate Income

Box 2 reports your portion of net rental real estate income or loss, already reduced by property-level items like mortgage interest, property taxes, and depreciation.⁴ For most partners this income is passive, which restricts your ability to use rental losses against wages or business income unless you qualify as a real estate professional or fit the $25,000 active participation exception.

Box 4: Guaranteed Payments

Guaranteed payments are amounts the partnership owes you for services or for the use of your capital regardless of whether the partnership had profits. Box 4a is for services, Box 4b for capital. Both are ordinary income to you. For general partners, Box 4a amounts also carry self-employment tax at a combined 15.3% rate: 12.4% Social Security on earnings up to $184,500 in 2026 and 2.9% Medicare on all earnings.⁵⁶ Confirm the partnership hasn’t rolled guaranteed payments into regular profit distributions. They aren’t taxed the same way.

Boxes 5, 6a, 6b, and 7: Investment Income

Box 5 is taxable interest. Box 6a is ordinary dividends, Box 6b is qualified dividends. Box 7 is royalties.³ Qualified dividends are taxed at long-term capital gains rates rather than ordinary rates, which is why they get their own line.

Boxes 8, 9, and 10: Capital Gains and Section 1231

Box 8 holds net short-term capital gains or losses; Box 9a holds net long-term. Boxes 9b and 9c isolate collectibles gains (taxed up to 28%) and unrecaptured Section 1250 gain from depreciated real property (taxed up to 25%). Box 10 shows net Section 1231 gains or losses from sales of business property held longer than a year. Section 1231 gets favorable asymmetric treatment: net gains are long-term capital, net losses are ordinary and offset ordinary income dollar-for-dollar.²

Box 13: Other Deductions

Box 13 is a catch-all keyed by letter code. The codes you’ll see most often:

Codes A through G report charitable contributions, split by type and AGI limitation.
Code H is investment interest expense, reported on Form 4952.
Code I covers deductions tied to royalty income, reported on Schedule E.
Code K is excess business interest expense, subject to the Section 163(j) limitation.
Code W is other deductions, which can include Section 754 basis adjustments if the partnership made that election.

If the partnership made a Section 754 election, the adjustment shows up under Code W. Check whether the amount is already reflected in Box 1 or Box 2 before you report it separately.

Where Each Box Goes on Your Individual Return

Routing errors are the most common K-1 filing mistakes. Each box lands on a specific place:

Box 1, ordinary business income: Schedule E, line 28. Material-participation income uses column (i) or (k); passive amounts use column (g) or (h).
Box 2, rental real estate: Schedule E, line 28, in the passive or nonpassive column depending on your participation.
Box 4, guaranteed payments: Schedule E, line 28, column (k), plus Schedule SE if subject to self-employment tax.
Box 5, interest income: Form 1040, line 2b.
Box 6a, ordinary dividends: Form 1040, line 3b. Box 6b, qualified dividends: Form 1040, line 3a.
Box 7, royalties: Schedule E, line 4.
Boxes 8 and 9, capital gains and losses: Schedule D, line 5 for short-term and line 12 for long-term.
Box 10, Section 1231: Form 4797, line 2.

The Partner’s Instructions include a full mapping of every box and code to the correct form and line, and it’s worth keeping open while you prepare the return.² Tax software routes items correctly if you enter the K-1 as it appears; it cannot rescue a figure entered in the wrong box.

Item L: Your Capital Account

Item L reconciles your capital account from the beginning to the end of the year:

Beginning balance, which should equal last year’s ending balance.
Plus capital contributed during the year (cash and fair market value of property).
Plus or minus your share of net income or loss from Part III.
Minus withdrawals and distributions.
Equals ending balance.

Partnerships report capital accounts on the tax basis method, which tracks your actual tax investment rather than book value.⁷ This matters when you take a distribution: if it exceeds your basis, the excess is taxable capital gain even though the partnership sold nothing.

Why the Losses on Your K-1 May Not Be Deductible This Year

Partnership losses run through four limitations in sequence. Getting stopped at any one carries the excess forward.

Basis Limitation

You can deduct losses only up to your adjusted basis in the partnership at year-end.⁸ Basis includes capital contributions, your share of partnership liabilities, and accumulated income, reduced by distributions and prior losses. Loss above basis is suspended until basis increases. This is why Item L matters beyond bookkeeping.

At-Risk Limitation

Losses that clear basis are then limited to the amount you have at risk.⁹ Your at-risk amount generally includes cash and property contributed plus recourse debt you’re personally liable for. It typically excludes nonrecourse debt, with a significant exception for qualified nonrecourse financing on real estate. Partners in leveraged partnerships often find at-risk is lower than basis.

Passive Activity Limitation

If you didn’t materially participate, the remaining loss is passive and can offset only passive income from other sources.¹⁰ The IRS uses seven material participation tests, the most common being more than 500 hours in the activity during the year. Rental real estate is passive by default unless you qualify as a real estate professional.

Excess Business Loss Limitation

For 2026, noncorporate taxpayers cannot deduct aggregate business losses above $256,000 for single filers or $512,000 for joint filers. Amounts above the threshold become a net operating loss carried forward. This cap applies after the passive rules, so it hits only losses from activities where you materially participate.

Deadlines and Penalties

Form 1065 and every attached K-1 are due by the 15th day of the third month after the partnership’s tax year ends. For calendar-year partnerships, that’s March 15. Your K-1 must arrive by that date, giving you about a month before your own April 15 deadline.²

A partnership can file Form 7004 by the original due date for an automatic six-month extension to September 15 for calendar-year filers.¹¹ That extension doesn’t extend your personal return. If you need the K-1 to file, file your own Form 4868.

Partnerships that file 10 or more returns of any type during the calendar year must e-file Form 1065. That threshold catches most active partnerships.

Late filing is expensive. For returns required to be filed in 2026, the penalty is $255 per partner for each month late, up to 12 months.¹² A 10-partner partnership three months late owes $7,650, even with no tax due, because Form 1065 is an information return and the penalty runs regardless.

If Your K-1 Is Wrong or Missing

Contact the partnership first and ask for a corrected schedule. A corrected K-1 has the “Amended K-1” box checked and is sent to both you and the IRS.

If the partnership won’t correct it, you have two paths. You can file using the figures you believe are correct and attach Form 8082 to notify the IRS of the inconsistent treatment.¹³ Filing inconsistently without Form 8082 lets the IRS assess a deficiency to match the partnership’s numbers, plus penalties. Or you can report the K-1 as issued and let the IRS resolve the discrepancy through audit, which means paying tax you dispute while you wait.

If you never receive a K-1, you’re still required to report your share of partnership income. Make a reasonable estimate from what you have and attach Form 8082 explaining why your amounts may differ from the partnership’s eventual filing.

Schedules K-2 and K-3 for International Items

If the partnership has foreign activity, foreign partners, or other international items, it may issue Schedules K-2 (partnership-level) and K-3 (your partner-level version) alongside the K-1. You need K-3 information to claim foreign tax credits and report foreign-source income correctly.

Many domestic partnerships qualify for a filing exception when they have no or limited foreign activity and all direct partners are U.S. citizens or resident aliens. A separate exception exists for small partnerships with total receipts under $250,000 and total assets under $1 million that file all K-1s on time. Even under an exception, you can request a K-3 from the partnership if you need one.

1
Office of the Law Revision Counsel. 26 USC 701 – Partners, Not Partnership, Subject to Tax
2
Internal Revenue Service. Partner’s Instructions for Schedule K-1 (Form 1065)
3
Internal Revenue Service. Schedule K-1 (Form 1065) Partner’s Share of Income, Deductions, Credits, etc.
4
Office of the Law Revision Counsel. 26 US Code 167 – Depreciation
5
Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
6
Social Security Administration. Contribution and Benefit Base
7
Internal Revenue Service. Notice 2021-13
8
Office of the Law Revision Counsel. 26 US Code 704 – Partner’s Distributive Share
9
Office of the Law Revision Counsel. 26 US Code 465 – Deductions Limited to Amount at Risk
10
Internal Revenue Service. Publication 925, Passive Activity and At-Risk Rules
11
Internal Revenue Service. About Form 7004, Application for Automatic Extension of Time To File Certain Business Income Tax, Information, and Other Returns
12
Internal Revenue Service. Rev. Proc. 2024-40
13
Internal Revenue Service. Instructions for Form 8082