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Schedule K-1. What it means and what you owe.
A K-1 shows up because you own part of a partnership, S-corp, or LLC taxed as one of those. It tells you (and the IRS) your share of the business's income, deductions, and credits — but the number rarely matches what you actually got paid. This guide walks through why, what the boxes mean, and how it lands on your 1040.
8 min read· Twin Cities, Minnesota
The short version
- What it is:a form issued by a partnership (Form 1065 K-1), S-corp (Form 1120-S K-1), or trust/estate (Form 1041 K-1) to report your share of the entity’s income/loss.
- Why it doesn’t match your bank deposits: K-1 reports your share of taxable income, not cash distributions. You can be taxed on income you didn’t receive (and vice versa).
- Where it goes: Schedule E of your 1040 for partnership / S-corp K-1s; various places (Schedule B, D, E) for trust / estate K-1s depending on income type.
- When you get it: partnerships and S-corps file March 15; K-1s often issued late. Many show up in late February through August. Plan for an extension if you’re waiting on one.
Why the K-1 number isn't what you got paid.
Pass-through entities (partnerships and S-corps) don’t pay tax themselves. Instead, the income passes through to owners, who report it on their personal returns. The K-1 is the IRS’s way of saying “here’s your share.”
Your share of the entity’s taxable income is what you’re taxed on — not the cash you actually received. So:
- Business made $200K profit, distributed $100K to a 50% partner. Partner’s K-1 shows $100K of income. They got $50K cash. They’re taxed on $100K.
- Business made $200K profit, distributed nothing (kept all profits in retained earnings). Partner’s K-1 still shows $100K of income. They got $0 cash. They still owe tax on $100K. This is “phantom income” — the classic K-1 problem.
- Business lost $50K, distributed $25K to a 50% partner. Partner’s K-1 shows a $25K loss, but they got $12,500 cash. The loss may or may not be deductible depending on basis (see below).
The boxes that matter most.
K-1s have a lot of boxes. The ones you care about for most situations:
Box 1 (ordinary business income / loss).Your share of the operating profit or loss. Goes on Schedule E Part II. This is the “real” income from running the business.
Box 2 (net rental real estate income). Passive activity by default, with the real-estate-professional exception. Goes on Schedule E Part I.
Box 3 (other rental income). Equipment rental, etc. Different rules than real estate.
Box 5 (interest income), Box 6 (dividends), Box 8 (capital gains/losses). These flow to the corresponding schedules on your 1040 (Schedule B for interest/dividends, Schedule D for capital gains). The entity is allocating these character types to you.
Box 14 (self-employment earnings on partnership K-1s only).If you’re a general partner or LLC member-manager, this is subject to self-employment tax. Limited partners typically have $0 here. S-corp K-1s don’t have this box — that’s the whole point of the S-corp election.
Box 17 (S-corp) or Box 20 (partnership) — codes for special items. Section 179, QBI components, foreign taxes, etc. Often the trickiest parts. We read these carefully.
Basis and at-risk rules.
You can only deduct losses up to your basis in the entity (rough version: cash and property you contributed, plus your share of cumulative income, minus distributions).
If a K-1 shows a $50,000 loss but your basis is only $20,000, you can deduct $20,000 this year. The remaining $30,000 carries forward until you have basis to absorb it.
For real estate partnerships and rental properties, there are additional “at-risk” and “passive activity” limits that often suspend losses for non-real-estate professionals. The tax software handles the math; the inputs have to be right.
When K-1s arrive late.
Partnerships and S-corps file by March 15 (or extend to September 15). K-1s have to be issued by the entity’s filing deadline, but in practice they trickle in throughout the spring and summer.
If you’re waiting on a K-1:
- File Form 4868 to extend your personal return to October 15. Free; takes 5 minutes online.
- Estimate the K-1 income and pay an extension payment by April 15 to cover what you’ll owe. The extension extends filing, not payment.
- When the K-1 arrives, complete the return with actual numbers. If you over-paid the estimate, get the difference back as a refund.
One year of late K-1s often turns into a habit if the partnership is large or slow. Plan for extensions every year if you’re a partner in something big.
Common K-1 traps to avoid.
- Not tracking basis. The partnership doesn’t track YOUR basis — you do. Without good basis records, losses can’t be verified and gains can be overtaxed at exit.
- Missing state K-1s. If the partnership has activity in multiple states, you may owe state tax in each. The federal K-1 doesn’t cover this; you need the state-specific schedules.
- Mixing K-1 income with distributions in your mental math.Income is what you’re taxed on; distribution is what you got paid. They’re different numbers and rarely match.
- Forgetting Box 17/20 codes. The numbered boxes only tell part of the story; the coded entries on the second page often carry real tax consequences (Section 179, QBI, foreign taxes).
- Receiving K-1 from a deal you forgot about.Real estate syndications, private placements, oil and gas partnerships — these issue K-1s for years after you invest. They show up in February and you forget what they are.
Got a K-1 and not sure what to do?