K-1 Tax Form: Income Boxes, Schedule E, and QBI Deduction

A K-1 tax form is the document a partnership, S corporation, trust, or estate sends you to report your share of its income, losses, deductions, and credits for the year. You get one because the entity itself generally doesn’t pay federal income tax; those tax items pass through to you, and you owe tax on your share whether or not the entity actually distributed cash. Every box on the K-1 maps to a specific line on your Form 1040, and misreading even one entry can mean overpaying or triggering an IRS notice.

Which K-1 Did You Receive?

There are three versions of the form, each tied to a different entity return. The version matters because the tax treatment, especially around self-employment tax, is not the same.

Partnership K-1 (Form 1065)

Partnerships issue this version to each partner, whether general, limited, or LLC member. The partnership files Form 1065 and sends you a K-1 showing your allocated share based on the partnership agreement, which is not necessarily an equal split.¹

Self-employment tax is the big distinction. A general partner who actively works in the business is typically subject to the combined 15.3% self-employment rate (12.4% Social Security plus 2.9% Medicare) on ordinary business income and guaranteed payments. Limited partners generally owe self-employment tax only on guaranteed payments for services, not on their share of ordinary business income, though the line between “limited” and “general” for SE purposes has been heavily litigated.²

S Corporation K-1 (Form 1120-S)

S corporations issue this version to shareholders. The entity files Form 1120-S, and each shareholder’s K-1 reports a pro rata share based on stock ownership. S corporations can’t specially allocate income to certain owners the way partnerships can.³

Shareholders generally don’t owe self-employment tax on K-1 income from an S corporation. The tradeoff is that any shareholder who works in the business must take a reasonable salary on a W-2, with standard payroll taxes withheld.⁴ The IRS can reclassify distributions as wages if compensation is unreasonably low.⁵

Estate and Trust K-1 (Form 1041)

Estates and trusts issue this version to beneficiaries. The fiduciary files Form 1041, and beneficiaries receive a K-1 for their share of income the entity distributed or was required to distribute. Income the trust or estate retains is taxed at the entity level, often at steep rates, since trusts hit the top bracket at relatively low income levels.⁶

Income keeps its character when it passes through. Qualified dividends stay qualified. Long-term capital gains stay long-term. That matters because those categories get preferential tax rates on your personal return.⁷

Reading the Income Boxes

Each version has its own box layout, but the partnership K-1 is the most detailed and common. The box numbers below refer to Form 1065 unless noted; S corporation and trust K-1s use different numbers for some of the same concepts.

Ordinary Business Income or Loss (Box 1)

Box 1 is the headline number: your share of the entity’s net profit or loss from core operations. On a partnership K-1, Box 1 may be subject to self-employment tax if you’re a general partner who materially participates. On an S corporation K-1, Box 1 flows to Schedule E without triggering SE tax.⁸ A loss in Box 1 is not automatically deductible; it has to pass four limitation tests covered further down.

Guaranteed Payments (Boxes 4a, 4b, 4c)

Guaranteed payments appear only on partnership K-1s. Box 4a reports payments for services, 4b reports payments for use of capital, and 4c is the total. These payments function like a salary: the partnership owes them regardless of profit.⁹ Guaranteed payments for services are nearly always subject to self-employment tax, and they reduce the partnership’s ordinary income in Box 1.

Rental Real Estate (Box 2)

Box 2 reports your share of income or loss from the entity’s rental real estate. This income is generally passive, so losses can only offset other passive income unless you qualify for the $25,000 rental allowance or meet the real estate professional rules discussed below.

Interest, Dividends, and Royalties (Boxes 5–7)

Box 5 is interest, 6a is ordinary dividends, 6b is qualified dividends taxed at preferential rates, and Box 7 is royalties. These figures combine with the interest and dividends reported directly to you on 1099s.⁹

Capital Gains (Boxes 8–10)

The K-1 breaks capital transactions into categories, each flowing to a different line on Schedule D:

Box 8: short-term capital gain or loss, taxed at ordinary rates.
Box 9a: long-term capital gain or loss, taxed at preferential rates.
Box 9b: collectibles gain, maximum 28% rate.
Box 9c: unrecaptured Section 1250 gain, maximum 25% rate.
Box 10: Section 1231 gain or loss from sale of business property held over one year.

All of these go to Schedule D and combine with capital transactions from your personal brokerage accounts.¹⁰

Self-Employment Earnings (Box 14, Partnership Only)

Box 14 tells you the amount subject to self-employment tax. It is generally the sum of Box 1 ordinary business income and Box 4a guaranteed payments for services. The figure transfers to Schedule SE, and half of the resulting SE tax is deductible as an adjustment to income on your 1040.²

Where the Numbers Land on Your 1040

Schedule E

Most K-1 business income ends up on Schedule E, Part II. You need a separate entry for each K-1, listing the entity’s name, EIN, and type. Box 1 ordinary business income flows into the income or loss column. Net rental real estate income from Box 2 goes to Schedule E, Part I, alongside any rental properties you own personally. The combined result from both parts flows to your Form 1040.¹¹

Schedules B and D

Interest from Box 5 and ordinary dividends from Box 6a go on Schedule B with your personal 1099 income. Qualified dividends from Box 6b are used to compute your preferential rate. Capital gains and losses from Boxes 8 through 10 flow to Schedule D, where they combine with brokerage transactions before the net result hits your 1040.¹⁰

Schedule A, Schedule SE, and Form 4562

Charitable contributions from the K-1 go on Schedule A with your personal itemized deductions. You still compare the total against the standard deduction to see which benefits you more. The Section 179 deduction passes through Form 4562, where it’s combined with any other Section 179 amounts and tested against annual dollar and income limits before flowing to Schedule E. Partnership Box 14 self-employment earnings transfer to Schedule SE for the actual tax calculation.²

Deductions and the QBI Deduction People Miss

Section 179

Section 179 lets you immediately write off the cost of qualifying business equipment instead of depreciating it over years. On a partnership K-1 it appears in Box 12; on an S corporation K-1 it’s in Box 11.⁹¹² For 2026, the maximum deduction is $2,560,000, phasing out dollar-for-dollar once the entity places more than $4,090,000 of qualifying property in service. Your share combines with Section 179 amounts from other sources on Form 4562. The total can’t exceed your aggregate taxable income from all active businesses; unused amounts carry forward.

Charitable Contributions (Box 13, Code A)

Your share of cash contributions made by a partnership is reported in Box 13, Code A. The entity doesn’t deduct these; you claim them on Schedule A subject to the same AGI-based percentage limits as personal charitable giving.¹³

Section 199A Qualified Business Income

One of the most valuable items on a K-1 is the data needed to claim the Section 199A deduction, worth up to 20% of qualified business income from partnerships and S corporations. It appears in Box 20, Code Z on a partnership K-1 and Box 17, Code V on an S corporation K-1. Instead of a dollar figure, you’ll often see “STMT,” pointing to an attached statement.¹⁴

That statement provides your share of qualified business income, the entity’s W-2 wages, and the unadjusted basis of qualified property, which you use to complete Form 8995 or Form 8995-A. At higher income levels, the deduction phases out for specified service businesses like law, accounting, health care, and consulting. For 2025, the phase-out begins at $197,300 for single filers and $394,600 for joint filers, with annual inflation adjustments.¹⁵

Many K-1 recipients miss this deduction because the data isn’t in a prominently labeled box; it’s in the attachment. If your K-1 includes a Section 199A statement, make sure it gets used.

Why Your K-1 Loss May Not Be Deductible

A loss on your K-1 doesn’t automatically reduce your taxable income. It has to survive four separate tests, applied in order. A loss blocked at any stage is suspended, not lost, and carries forward.

Basis

You can deduct losses only up to your tax basis in the entity. Basis starts with what you invested, increases with income and additional contributions, and decreases with losses, deductions, and distributions. If a loss exceeds basis, the excess is suspended until basis is restored.¹¹ S corporation shareholders who claim a loss, take a distribution, or dispose of stock must file Form 7203 to prove basis supports the deduction.¹⁶

At-Risk

Losses that clear basis then face the at-risk rules. You’re at risk for amounts you invested plus amounts you personally borrowed for use in the activity. Nonrecourse loans generally don’t count, with an important exception for qualified nonrecourse financing secured by real property. The rule prevents deducting losses backed by money you could walk away from.

Passive Activity

Losses that pass at-risk then face the passive activity rules. If you don’t materially participate, the activity is passive, and passive losses can only offset passive income. They can’t reduce wages, interest, or other non-passive income.

Rental real estate has one significant carve-out. If you actively participate in managing a rental, you can deduct up to $25,000 of rental losses against non-passive income. The allowance phases out by $1 for every $2 your modified AGI exceeds $100,000 and disappears at $150,000.¹⁷ Taxpayers who qualify as real estate professionals, spending more than 750 hours per year in real property trades or businesses and materially participating in each rental, can treat rental losses as non-passive.

Excess Business Loss

Any loss that survives the first three tests faces a final cap. For 2026, you can’t deduct business losses exceeding $256,000 (single) or $512,000 (joint) against non-business income. Amounts above the threshold become a net operating loss carryforward.

Net Investment Income Tax

K-1 income that qualifies as net investment income, including rental income, interest, dividends, capital gains, and income from passive business activities, may trigger an additional 3.8% tax. The Net Investment Income Tax applies when modified AGI exceeds $200,000 (single), $250,000 (joint), or $125,000 (married filing separately). These thresholds are set by statute and not adjusted for inflation.¹⁸

The tax is calculated on Form 8960 and equals 3.8% of the lesser of your net investment income or the amount by which your MAGI exceeds the threshold. Income from a business you materially participate in is generally excluded, so Box 1 ordinary business income from a partnership where you actively work isn’t hit. The same income is subject to NIIT if you’re a passive investor.

Tracking Your Basis

Your tax basis is a running investment balance in the entity. It starts with your contribution, climbs with income allocations and additional contributions, and drops with loss deductions and distributions. Accurate records aren’t optional. Basis determines whether losses are deductible, whether distributions are tax-free returns of capital or taxable, and what gain or loss you recognize when you sell your interest.

S corporation shareholders must attach Form 7203 whenever they claim a loss, receive a non-dividend distribution, or sell stock.¹⁶ Partnership basis tracking has no dedicated IRS form, but the consequences of getting it wrong are the same. If you can’t prove basis, the IRS can deny your losses. Reconstructing years of basis calculations after the fact is one of the most painful exercises in tax compliance; keep the record current even in years no form is required.

When the K-1 Is Late

Partnerships and S corporations must file and furnish K-1s by the 15th day of the third month after the entity’s year end, meaning March 15 for calendar-year entities.¹⁹ That’s a month before your April 15 individual deadline, but many entities file an automatic six-month extension on Form 7004, which can push your K-1 arrival to September.

A late K-1 almost always means you need to extend your own return. File Form 4868 by April 15 for an automatic six-month extension to October 15. The extension only buys time to file, not time to pay. You still owe interest on any unpaid tax from April 15 forward, and you may owe a late payment penalty of 0.5% per month on the balance.²⁰

To avoid underpayment penalties, pay at least 90% of your actual 2026 liability by April 15. Alternatively, meet the safe harbor by paying 100% of the tax shown on your 2025 return, or 110% if your 2025 AGI exceeded $150,000 ($75,000 if married filing separately).²¹ When you’re waiting on a K-1, the prior-year safe harbor is usually the practical route. You know that number, and meeting it protects you from penalties regardless of what the K-1 eventually shows.

When the K-1 Is Wrong or Gets Amended

If a corrected K-1 arrives after you’ve filed, you’ll generally need to file Form 1040-X. Enter your original figures in Column A, the changes in Column B, and corrected amounts in Column C. Attach the corrected K-1 and any affected schedules. Amended returns typically take 8 to 12 weeks to process.²²

If you believe the K-1 is wrong and the entity won’t correct it, you have two options. You can report the K-1 as issued and wait for the entity to sort things out. Or you can report the amounts you believe are correct and attach Form 8082 (Notice of Inconsistent Treatment), explaining which line you disagree with, what the entity reported, what you’re reporting, and why.²³ Filing Form 8082 puts the IRS on notice of the disagreement and protects you from penalties for inconsistent reporting. Reporting different amounts without Form 8082 can trigger an automatic assessment.

Foreign Income and Schedule K-3

If the entity has foreign income, foreign taxes paid, or foreign partners, you may receive Schedule K-3 alongside your K-1. The K-3 provides the detail you need to claim foreign tax credits, report foreign-source income, and complete related international forms.²⁴ If your K-1 has an amount in Box 16 (indicating a K-3 is attached) or Box 21 (foreign taxes paid), account for those items. Ignoring a K-3 can mean leaving foreign tax credits on the table or failing to report required international information.

1
Internal Revenue Service. Instructions for Form 1065 (2025) – Section: Schedules K and K-1
2
Internal Revenue Service. Instructions for Form 1065 (2025) – Section: Net Earnings From Self-Employment
3
Internal Revenue Service. Instructions for Form 1120-S (2025) – Section: Shareholders Pro Rata Share Items
4
Internal Revenue Service. S Corporation Employees, Shareholders and Corporate Officers
5
Internal Revenue Service. S Corporation Compensation and Medical Insurance Issues
6
Internal Revenue Service. Instructions for Form 1041 and Schedules A, B, G, J, and K-1 (2025) – Section: Schedule K-1
7
Internal Revenue Service. 2025 Instructions for Schedule K-1 (Form 1041) for a Beneficiary Filing Form 1040 or 1040-SR
8
Internal Revenue Service. 2025 Partners Instructions for Schedule K-1 (Form 1065) – Section: Box 1
9
Internal Revenue Service. Schedule K-1 (Form 1065) 2025
10
Internal Revenue Service. Partners Instructions for Schedule K-1 (Form 1065) (2025) – Section: Income (Loss)
11
Internal Revenue Service. 2025 Partners Instructions for Schedule K-1 (Form 1065)
12
Internal Revenue Service. 2025 Schedule K-1 (Form 1120-S)
13
Internal Revenue Service. 2025 Instructions for Form 1065 – Section: Line 13a Cash Contributions
14
Internal Revenue Service. Shareholders Instructions for Schedule K-1 (Form 1120-S) – Section: Box 17 Code V
15
Internal Revenue Service. Instructions for Form 8995 (2025)
16
Internal Revenue Service. Instructions for Form 7203
17
Office of the Law Revision Counsel. 26 USC 469 – Passive Activity Losses and Credits Limited
18
Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax
19
Internal Revenue Service. Publication 509 (2026), Tax Calendars
20
Internal Revenue Service. Form 4868 – Application for Automatic Extension of Time To File U.S. Individual Income Tax Return
21
Internal Revenue Service. 2026 Form 1040-ES (NR) Instructions
22
Internal Revenue Service. Instructions for Form 1040-X (Rev. December 2025)
23
Internal Revenue Service. Instructions for Form 8082 (Rev. October 2025)
24
Internal Revenue Service. Form 1065, Schedules K-2 and K-3 Filing Requirements