What Is a K-1 Form? (And What Do You Do With It?)

What a K-1 actually is

When you own part of a pass-through entity — a partnership, S-corporation, trust, or estate — the entity doesn’t pay income tax itself. Instead, its income, deductions, and credits “pass through” to the owners, who report them on their personal returns.

A K-1 is the form that tells you your share of those results. Think of it like a W-2 or 1099, except instead of reporting wages or payments, it reports your portion of an entity’s tax picture.

Who issues K-1s

You may receive a K-1 as an investor in a real estate partnership or private fund, as an S-corp owner, as a partner in a business, or as a beneficiary of a trust. Each K-1 gets entered into your personal return and affects your tax bill.

The phantom income problem

This is the part that trips people up. You owe tax on K-1 income based on your allocated share of the entity’s profit — regardless of whether you received any cash.

Example: you’re an investor in a real estate partnership. The partnership shows a $40,000 profit for the year and your K-1 shows your 25% share: $10,000 in income. But the partnership didn’t distribute any cash — it reinvested the profit. You still owe income tax on $10,000. No cash in hand, real tax bill.

This is called phantom income. It’s especially common in real estate deals and growing businesses where profit is retained rather than distributed. If you have K-1 investments, factor this into your quarterly estimates — phantom income can be a large, unexpected addition to your tax bill.

K-1 boxes you’ll actually see

K-1 forms are dense. Most of the boxes won’t apply to you. Here are the ones that typically matter for a business owner:

• Ordinary business income (or loss)— your share of the entity’s net operating income. This is what most people are looking for.
• Net rental real estate income — if the entity holds rental property.
• Section 179 deduction— your share of the entity’s equipment expensing.
• Self-employment earnings — shown on partnership K-1s for general partners; subject to SE tax. Not shown on S-corp K-1s.
• QBI information— the data your software needs to calculate the 20% QBI deduction if you’re eligible.

S-corp owners: you have both a W-2 and a K-1

If you own and work in your S-corp, you receive two separate tax documents from it each year:

1. W-2 — your salary. Subject to payroll taxes (Social Security and Medicare). Goes on your 1040 as wages.
2. K-1 — your share of the pass-through profit above your salary. Not subject to SE tax. Goes on your 1040 as pass-through income.

Both end up on your personal return and are subject to income tax. But only the W-2 wages are subject to payroll/SE tax — the K-1 income is not. This split is exactly why the S-corp structure saves on SE tax.

What to do when your K-1 arrives

1. Don’t file your return until you have it.If you file without a K-1 you’re expecting, you may need to amend. Just extend.
2. Hand it directly to your CPA or enter it in your tax software. It goes on Schedule E (passive income), or Schedule SE if it has SE income, plus potentially Form 8995 for the QBI calculation. Your software should prompt you.
3. Check for phantom income. If the K-1 shows more income than cash you received, plan for the tax bill. Make a quarterly estimated payment if needed.