Schedule K-1 Explained: How Partners, S-Corp Shareholders & Trust Beneficiaries Are Taxed

If you own a piece of a partnership, an S-corporation, a multi-member LLC, or you’re a beneficiary of a trust or estate, the Schedule K-1 is the single most important tax document you’ll receive that year. It tells you how much of the entity’s income, deductions, and credits flow through to you — to be reported on your personal 1040.

Unlike a W-2 or 1099, a K-1 isn’t a simple summary. It’s a multi-page form with dozens of boxes, each routing somewhere specific on your return. Get the routing wrong and you misreport income, miss deductions, or trigger an IRS notice.

This guide walks through all three K-1 variants (Forms 1065, 1120-S, 1041), the boxes that drive your 1040, the basis / at-risk / passive activity limits that gate your losses, and the common mistakes.

What Is a K-1 (and Why You Get One)

Pass-through entities don’t pay federal income tax themselves. Instead, their income, deductions, and credits “pass through” to their owners or beneficiaries, who pay tax on their personal returns.

The K-1 is the annual statement showing each owner’s / beneficiary’s share. The entity files a copy with the IRS along with its own return (Form 1065, 1120-S, or 1041), and sends a copy to each K-1 recipient.

Three pass-through entity types issue K-1s:

• Partnerships and multi-member LLCs taxed as partnerships issue Form 1065 Schedule K-1.
• S-corporations issue Form 1120-S Schedule K-1.
• Trusts and estates issue Form 1041 Schedule K-1.

Single-member LLCs (disregarded entities), sole proprietors, and C-corps don’t issue K-1s. C-corp shareholders get a 1099-DIV for dividends; sole-prop / disregarded-entity income flows directly on Schedule C of the owner’s 1040.

Form 1065 K-1: Partnerships and Multi-Member LLCs

The 1065 K-1 has three parts: entity info, partner info, and the share of items.

Part III box-by-box

Box	Item	Where it goes on 1040
1	Ordinary business income (loss)	Schedule E Part II
2	Net rental real estate income (loss)	Schedule E Part II (passive)
3	Other net rental income (loss)	Schedule E Part II
4a–4c	Guaranteed payments (services / capital / total)	Schedule E Part II (and Schedule SE for service partners)
5	Interest income	Schedule B
6a–6b	Ordinary / qualified dividends	Schedule B
7	Royalties	Schedule E Part I
8	Net short-term capital gain (loss)	Schedule D / Form 8949
9a	Net long-term capital gain (loss)	Schedule D / Form 8949
9b	Collectibles (28% rate) gain	Schedule D worksheet
9c	Unrecaptured §1250 gain	Schedule D worksheet
10	Net §1231 gain (loss)	Form 4797
11	Other income items (various codes)	Per instructions
13	Other deductions (various codes)	Per instructions
14	Self-employment earnings	Schedule SE (general partners + LLC members deemed active)
15	Credits	Various credit forms
16	Foreign transactions	Form 1116 + Schedule K-3
17	AMT items	Form 6251
18	Tax-exempt income / non-deductible expenses	Basis adjustments
19	Distributions (cash, property)	Reduces outside basis
20	Other information (codes Z = §199A, AE = excess business interest, etc.)	Per instructions
21	Foreign taxes paid / accrued	Form 1116

The 2026 form added Schedule K-3 as the standalone international-information schedule; if your partnership has any foreign activity, you’ll get a K-3 alongside the K-1.

Box 14 SE earnings — the partnership-vs-S-corp difference

Box 14 reports your share of self-employment earnings, which feeds Schedule SE and triggers a 15.3% (12.4% SS up to wage base + 2.9% Medicare) SE tax on top of income tax.

General partners and active LLC members (under the proposed §1402(a)(13) regs and the Renkemeyer line of cases) are typically subject to SE tax on their share of ordinary business income plus guaranteed payments for services.

Limited partners are generally exempt from SE tax on their distributive share but pay SE tax on guaranteed payments. The line between “limited partner” and “active LLC member” is one of the most-litigated areas in partnership tax.

This is the key difference vs. an S-corp: S-corp K-1 ordinary income is not SE income. S-corp shareholders pay FICA only on their W-2 wages, not on their K-1 box 1 distributive share — the basis for the “S-corp salary optimization” strategy.

Box 19 distributions — not taxable income

A frequent mistake: Box 19 (“Distributions”) is not added to your income. Distributions reduce your outside basis. They become taxable only if they exceed your outside basis (then the excess is a §731(a)(1) capital gain).

Form 1120-S K-1: S-Corporations

S-corp K-1 has a similar structure but different box numbering and different distributive treatment.

Part III highlights

Box	Item	Where it goes
1	Ordinary business income (loss)	Schedule E Part II (NOT SE-taxed)
2	Net rental real estate income (loss)	Schedule E Part II
3	Other net rental income (loss)	Schedule E Part II
4	Interest income	Schedule B
5a–5b	Ordinary / qualified dividends	Schedule B
7	Net short-term capital gain (loss)	Schedule D
8a	Net long-term capital gain (loss)	Schedule D
9	Net §1231 gain (loss)	Form 4797
11	§179 deduction	Form 4562
12	Other deductions	Various
13	Credits	Various
14	Foreign transactions	Form 1116 / K-3
15	AMT items	Form 6251
16	Items affecting shareholder basis (tax-exempt, distributions, non-deductible)	Basis tracking
17	Other information (code V = §199A QBI info)	Per instructions

Box 1 is not self-employment income

This is the single biggest practical advantage of the S-corp structure. S-corp ordinary business income flowing through Box 1 is taxed as ordinary income on your 1040 but is not subject to self-employment tax.

In exchange, the S-corp must pay the owner a reasonable compensation W-2 wage for services rendered (audit risk if you pay yourself $0 wages and take everything as Box 1 distributions). The IRS Fact Sheet 2008-25 and case law (Watson v. Commissioner, Sean McAlary, Glass Blocks Unlimited) define the reasonable-comp standard.

Reasonable comp + Box 1 distributive share is the “S-corp salary optimization” play that drives the LLC vs. S-Corp tax comparison decision.

Distributions in excess of basis = capital gain

For S-corps, distributions in excess of your stock basis are taxed as a capital gain under §1368(b)(2) (assuming no E&P from former C-corp years). Track basis annually.

Form 1041 K-1: Trusts and Estates

The 1041 K-1 distributes the trust/estate’s distributable net income (DNI) to beneficiaries who received distributions during the year. The character of the income (interest, dividends, capital gains) flows through retains its identity.

Part III highlights

Box	Item	Where it goes
1	Interest income	Schedule B
2a–2b	Ordinary / qualified dividends	Schedule B
3	Net short-term capital gain	Schedule D (if distributed; else taxed at trust level)
4a–4c	Net long-term capital gain (incl. 28%-rate and unrecaptured §1250)	Schedule D
5	Other portfolio and nonbusiness income	Schedule E
6	Ordinary business income	Schedule E
7	Net rental real estate income	Schedule E (passive)
8	Other rental income	Schedule E
9	Directly apportioned deductions	Various
10	Estate tax deduction (IRD)	Schedule A
11	Final-year deductions (incl. excess deductions on termination)	Various
12	AMT items	Form 6251
13	Credits	Various
14	Other information (incl. §199A info, foreign tax, NIIT amounts)	Per instructions

Capital gains are often not distributed

A frequent surprise: under §643(a)(3) and the related regs, capital gains are generally allocated to principal (corpus) rather than DNI, and therefore stay inside the trust to be taxed at trust rates. Trust capital gains brackets are highly compressed — the 20% LTCG bracket starts at around $15,200 of taxable income (2024 figure; small inflation adjustments since). That’s why high-DNI trusts often elect to allocate capital gains to DNI under the trust agreement to push them to lower-bracket beneficiaries.

Basis Tracking: §704(d) and §1366(d)

Loss deductions are limited to your basis in the entity. Without sufficient basis, losses are suspended and carried forward until basis is restored.

Partnership outside basis (§704)

Increased by:

• Cash and property contributions
• Allocated share of partnership income (taxable and tax-exempt)
• Allocated share of partnership liabilities (recourse and qualified non-recourse)

Decreased by:

• Distributions
• Allocated share of partnership losses
• Allocated share of liability reductions
• Non-deductible expenses

The partnership doesn’t always track your outside basis — you do. Keep a running spreadsheet. Form 1065 K-1 Part II Item L (Capital Account Analysis) shows your capital account, which is not the same as outside basis but is a useful starting point.

S-corp basis (§1366(d) + §1367)

S-corps track two basis figures:

• Stock basis — the §1367 calculation similar to partnership outside basis but excluding entity-level debt.
• Debt basis — limited to loans the shareholder personally makes to the corporation (NOT loans the S-corp owes to a bank, even if the shareholder personally guarantees them — see Selfe v. United States).

Losses first reduce stock basis to zero, then debt basis to zero. Suspended losses carry forward. Form 7203 (“S Corporation Shareholder Stock and Debt Basis Limitations”) is now required to be attached to your 1040 when you claim S-corp losses, deduct distributions in excess of basis, dispose of stock, or receive a loan repayment.

At-Risk Rules (§465) — Form 6198

Even if you have basis, losses are further limited to amounts you have personally at risk — cash and property contributed plus recourse debt you’re personally liable for (no qualified nonrecourse partnership debt). Borrowed-from-related-party amounts and nonrecourse debt don’t count.

File Form 6198 if at-risk rules limit a loss. Suspended at-risk losses carry forward.

Passive Activity Loss Rules (§469) — Form 8582

Passive losses can only offset passive income. Two types of activities are automatically passive:

1. Rental activities (with narrow exceptions for real estate professionals under §469(c)(7)).
2. Trade or business activities in which you do not “materially participate” under the §469(h) tests (500 hours, “substantially all,” etc.).

Limited partner interests are presumptively passive (rebuttable by meeting §469 material participation tests).

Suspended passive losses carry forward indefinitely. They’re released when you have:

• Passive income from any source, or
• A complete disposition of your entire interest in the activity to an unrelated party under §469(g) — at which point all suspended losses become fully deductible.

File Form 8582 to compute the current-year passive limit and track suspended losses.

§199A QBI Deduction — Codes Z (1065) and V (1120-S)

The 20% Qualified Business Income deduction is reported via:

• 1065 K-1 Box 20 code Z with statement showing QBI, W-2 wages, UBIA of qualified property
• 1120-S K-1 Box 17 code V with the same statement

You claim the deduction on:

• Form 8995 if your taxable income is below the threshold (2025: $241,950 single / $483,900 MFJ — verify the current-year figure)
• Form 8995-A if above the threshold (introduces W-2 wage / UBIA limits and the SSTB phaseout)

Specified Service Trades or Businesses (SSTB — health, law, accounting, consulting, financial services, etc.) phase out the QBI deduction entirely above the upper threshold.

The QBI deduction was originally scheduled to sunset after 2025 but was extended and modified by the One Big Beautiful Bill Act (OBBBA) in 2025. Confirm current-year rules before applying old assumptions.

What to Do If Your K-1 Arrives Late

Pass-through entities file by March 15 (or get an automatic 6-month extension to September 15 via Form 7004). Most K-1s arrive in late March or early April. Many arrive in September.

If you don’t have your K-1 by April 15:

1. File Form 4868 to extend your 1040 to October 15. Pay your best estimate of tax owed with the extension — Form 4868 extends filing, not payment.
2. Don’t guess and amend later. Estimating K-1 numbers and filing leads to messy 1040-X amendments. Better to extend.
3. Demand a status update from the entity’s tax preparer. You have the right to know when the K-1 will be issued.

Common Mistakes

1. Treating distributions (Box 19 / 16) as income. They’re not — they reduce basis.
2. Missing the §199A info (Box 20 code Z or Box 17 code V). Easy to overlook in the statements appended to the K-1.
3. Not tracking basis year over year. You’ll over-deduct losses now and over-pay tax on dispositions later.
4. Filing 1040 from the entity’s K-1 draft. Drafts get revised. Wait for the final.
5. Ignoring AMT preferences (Box 17 / 12). Pass-through AMT items can drag a non-AMT 1040 into AMT.
6. Forgetting Form 7203 for S-corp losses or distributions. Required attachment as of 2022 returns onward.
7. Skipping Schedule K-3 if you have any foreign activity. Form 1116 foreign tax credit calculation needs the K-3 detail.

FAQs

My K-1 shows a loss but I can’t deduct it. Why?

Three limits gate K-1 losses, applied in order: (1) outside basis under §704(d) / §1366(d), (2) at-risk under §465 via Form 6198, (3) passive activity under §469 via Form 8582. If any limit pins your deduction to zero, the unused loss is suspended and carries forward until that limit releases.

Do I owe self-employment tax on K-1 income?

It depends on the K-1 type and your role. Partnership (1065) K-1 box 14 reports SE earnings — usually all for general partners and active LLC members, only guaranteed-payments-for-services for limited partners. S-corp (1120-S) K-1 box 1 is not SE income; only your W-2 wages from the S-corp are subject to FICA. Trust (1041) K-1 income is generally not SE income unless the trust is operating an active trade or business.

What’s the deadline to issue K-1s?

Form 1065 partnerships and Form 1120-S S-corps must file (and issue K-1s) by March 15, extendable to September 15 with Form 7004. Form 1041 trusts/estates file by April 15 (calendar-year), extendable to September 30 for trusts / October 15 for estates via Form 7004. The IRS imposes per-K-1 penalties (around $290 per K-1 for 2024 returns) for entities that fail to furnish on time, but enforcement is light.

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Try the calculator: S-Corp vs. LLC Tax Comparison — model the FICA savings of an S-corp election vs. partnership / sole-prop treatment.

Related guides:

• LLC vs. S-Corp tax comparison
• Self-employment tax: how it works
• Passive activity loss rules for real estate investors