How to Read a Schedule K-1: A Primer

A Schedule K-1 (Form 1065) reports your share of a partnership's income, deductions, credits, and distributions for the year. Because partnerships pay no entity-level federal income tax, every item of income flows through to the partners, who report it on their own returns whether or not they received any cash. Reading a K-1 means understanding three parts: who the partnership is (Part I), who you are to the partnership (Part II), and what you must report (Part III, boxes 1 through 23). This primer walks through each in plain language.

If you invest in private funds, a family limited partnership, an LLC taxed as a partnership, or rental real estate held in an entity, the K-1 is how the tax consequences reach you. It is also the document clients ask about most in March, usually because it has not arrived yet. That is normal, as we explain below.

The big idea: you are taxed on income, not on cash

The single most important concept on a K-1 is that taxable income and cash distributions are different things. A fund can allocate you $50,000 of taxable income while distributing nothing, often called phantom income, or distribute $100,000 of cash that is largely a nontaxable return of your own capital. The income boxes (1 through 11) drive your tax bill; the distribution box (19) mostly drives your basis, the running measure of your investment that determines whether future distributions or the eventual sale produce gain. Keep that distinction in mind and the rest of the form becomes far less mysterious.

Part I and Part II: the who and the how much

Part I identifies the partnership: its employer identification number, name and address, and a checkbox (item D) indicating whether it is a publicly traded partnership. PTPs follow special loss rules, so that box matters more than it looks.

Part II describes your stake:

• Items E through H identify you and classify you as a general or limited partner, domestic or foreign. For an IRA investor, item I2 flags the partner as a retirement plan, the first clue that UBTI rules (discussed below) may apply.
• Item J shows your percentage share of profit, loss, and capital at the beginning and end of the year. In a private fund these rarely match your headline ownership because of the waterfall.
• Item K1 lists your share of the partnership's liabilities (nonrecourse, qualified nonrecourse financing, and recourse). Liabilities matter because they add to your basis and can support deducting losses, especially in leveraged real estate.
• Item L, the capital account analysis, is a one-paragraph history of your year: beginning capital, contributions, your share of net income or loss, other adjustments, withdrawals and distributions, and ending capital. Since the 2020 tax year the IRS requires this on a tax basis, making item L the closest thing the form has to a basis tracker. It is not your full tax basis (your share of liabilities sits outside it), but watching it move year to year tells most of the story.
• Items M and N flag contributed property with built-in gain or loss and Section 704(c) amounts, which mostly concern partners who contributed appreciated assets, common in family limited partnerships.

Part III: the boxes, in plain language

Part III is where the numbers you report actually live. On the current form the boxes run 1 through 23.

• Box 1, ordinary business income or loss. Your share of the operating result. For most passive investors this lands on Schedule E of your Form 1040 and, if it is a loss, may be suspended by the passive activity rules until you have passive income or exit.
• Box 2, net rental real estate income or loss. The same idea for rental property operations. Real estate funds and family real estate LLCs report here.
• Box 3, other net rental income. Rentals that are not real estate, such as equipment.
• Boxes 4a through 4c, guaranteed payments. Fixed payments to partners for services or capital, common in operating businesses and professional firms, rare in passive funds.
• Box 5, interest income; boxes 6a through 6c, dividends; box 7, royalties. Portfolio income passed through in character. Qualified dividends in 6b keep their preferential rate on your return; the K-1 preserves the character of each income type as if you had earned it directly. Our primer on how investment income is taxed explains those characters.
• Boxes 8 and 9a, net short-term and long-term capital gains. Fund sales of portfolio positions flow through here. Boxes 9b (collectibles) and 9c (unrecaptured Section 1250 gain from depreciated real estate) carry special rates.
• Box 10, net Section 1231 gain or loss. Gains from business or rental property sales, which enjoy a favorable hybrid character: net gains are capital, net losses are ordinary.
• Box 11, other income. A catch-all with letter codes, frequently used by trading funds for items like Section 475 mark-to-market income.
• Box 12, Section 179 deduction; box 13, other deductions. Box 13's codes include charitable contributions and investment interest expense, items that must run through your own return's limits rather than simply reducing box 1.
• Box 14, self-employment earnings. Relevant for general partners and active LLC members, not for passive limited partners.
• Box 15, credits.
• Box 16, Schedule K-3 checkbox. If checked, a separate Schedule K-3 with international detail (foreign income, foreign taxes by country) is attached or coming. Your CPA needs it to claim foreign tax credits.
• Box 17, alternative minimum tax items; box 18, tax-exempt income and nondeductible expenses. Box 18 also reports nondeductible items that still reduce your basis.
• Box 19, distributions. The cash and property you actually received. Distributions are generally tax-free up to your basis; they reduce basis rather than create income. Cash distributions above basis produce capital gain, which is why basis tracking matters.
• Box 20, other information. The deepest box on the form, with dozens of letter codes. Three appear constantly: code A (investment income for the investment interest limitation), code Z (Section 199A information supporting the qualified business income deduction), and code V (unrelated business taxable income, discussed next).
• Box 21, foreign taxes paid or accrued; boxes 22 and 23, checkboxes flagging multiple activities for at-risk and passive purposes, which tell your CPA the attached statements must be tracked activity by activity.

A hypothetical K-1, decoded

Consider a hypothetical investor with a $500,000 commitment to a private real estate fund, $400,000 of it called so far. Her year-three K-1 shows box 2 rental loss of $18,000, box 5 interest of $4,000, box 9a long-term capital gain of $22,000, and box 19 cash distributions of $30,000. Item L shows beginning capital of $385,000 and ending capital of $363,000.

On her return, the $4,000 of interest and $22,000 of long-term gain are taxable this year, the gain at preferential rates. The $18,000 rental loss is passive; with no other passive income, it is suspended and carried forward, not deducted. The $30,000 distribution is tax-free because it is well within her basis; it simply reduces her capital account, which is why item L declined. Net result: $30,000 of cash received, $26,000 of income reported, and $18,000 of losses in reserve for a future passive-income year or the fund's wind-down. This example is hypothetical and simplified.

What are basis and at-risk limits, conceptually?

You can only deduct partnership losses to the extent of your basis: roughly, what you put in, plus income allocated to you and your share of liabilities, minus distributions and prior losses. Losses beyond basis are suspended, not lost. A second gate, the at-risk rule, limits deductions to amounts you could actually lose economically. A third gate, the passive activity rules, defers passive losses if you lack passive income. Most limited partners clear the first two gates and park losses at the third until a sale or income year frees them. You do not need to compute any of this yourself, but knowing why a K-1 loss did not appear as a deduction on your 1040 prevents a lot of confusion.

Why does my IRA care about code V?

If a partnership held inside an IRA generates unrelated business taxable income, typically from an operating business or from debt-financed income such as leveraged real estate, the IRA itself can owe tax. Box 20, code V reports your share. If an IRA's gross UBTI across all holdings exceeds $1,000 in a year, the custodian must file Form 990-T and pay tax from the IRA, per IRS instructions. Many private funds offer blocker structures to shield retirement investors; ask before subscribing, not after.

State K-1s and composite returns

Partnerships operating in multiple states usually issue state K-1s allocating income to each state, which can create nonresident filing obligations for you. Many partnerships offer relief through composite returns, where the partnership files and pays one return on behalf of nonresident partners, or through state withholding credited to you. Composite filing is convenient but sometimes costs more than filing yourself, since composite rates are often the state's top rate. Wisconsin residents also receive a credit for taxes paid to other states, so coordinating the K-1 package with your home-state return is a CPA-level task.

Why do K-1s arrive so late?

Partnership returns are due March 15, but a six-month extension to September 15 is routine, and a fund of funds cannot finish its K-1s until every underlying fund delivers its own. Layer two or three tiers of partnerships and a September arrival is normal, not negligent. Practically, private fund investors should plan to extend their personal returns every year. Extending is not an audit flag; it is the standard rhythm of private markets investing, and paying a good-faith estimate by April 15 avoids penalties. Many funds issue spring estimates so your CPA can set that payment intelligently.

What does your CPA actually need?

Send the entire K-1 package, not just the first page: the supplemental statements behind boxes 11, 13, and 20, the Schedule K-3 if box 16 is checked, all state K-1s, and any footnotes about composite elections or withholding. The footnotes frequently contain the numbers that matter most, including UBTI detail and 199A breakdowns. For your own records, keep subscription documents, capital call and distribution notices, and each year's item L; together they let anyone reconstruct basis when the investment winds down.

Key numbers

Frequently asked questions

I received a K-1 but no cash. Do I really owe tax?Often yes. Partnerships allocate taxable income to partners regardless of distributions. The cash typically comes later; the tax does not wait for it.

My K-1 shows a big distribution in box 19 but little income. Is that taxable?Usually not. Distributions up to your basis are a return of capital, not income. Only distributions exceeding basis create gain.

Do I need to file in other states because of a K-1?Possibly. State K-1s showing allocated income can trigger nonresident filings unless the partnership filed a composite return or withheld on your behalf. Your CPA should review the state package each year.

What is the difference between a 1065 K-1 and the K-1s from S corporations or trusts?Same concept, different forms: Form 1120-S K-1s come from S corporations, Form 1041 K-1s from trusts and estates. Box numbers and rules differ.

Why is my capital account in item L negative?Usually because distributions and allocated losses have exceeded contributions and income, common in leveraged real estate. It is not automatically a problem, but it often signals gain to come at exit.

Can I just ignore box 20?No. Box 20 carries the qualified business income deduction detail, UBTI, and investment interest inputs. Skipping its statements is the most common way K-1 returns get prepared wrong.

Where to go deeper

This primer pairs with several related Atlatl Advisers pieces. How Private Market Funds Work: A Primer explains the fund structures, capital calls, and waterfalls that generate these K-1s in the first place. Family Limited Partnerships covers the estate planning entities that produce K-1s for many families. Real Estate and Taxes: 1031 Exchanges, Cost Segregation, and Passive Losses goes deeper on the rental and depreciation items that flow through boxes 2, 9c, and 10. And How Investment Income Is Taxed: A Primer explains the rate treatment each character of income receives once it lands on your return.