U.S. · Tax forms
K-1 box 20 code Y.
Extra net investment income information for Form 8960 and the 3.8% NIIT.
Box 20, code Y is net investment income (NII) information the partnership may provide to help you figure the net investment income tax (NIIT) under section 1411, covering items not reported elsewhere on Schedule K-1 or K-3. It is used for information about income from controlled foreign corporations (CFCs) and passive foreign investment companies (PFICs) that is not provided elsewhere on Schedule K-3. U.S. citizens and residents, and domestic trusts and estates, follow the Instructions for Form 8960. Corporate partners are not subject to the NIIT.
Look up a NIIT item
Result
Code Y and related notes
| Item | Meaning | Where it goes (per the IRS instructions) |
|---|---|---|
| 20-Y | Box 20, code Y: Net investment income (NII) | Information you may need to determine your NIIT under section 1411 that is not reported elsewhere on Schedule K-1 or K-3 |
| 8960 | Form 8960 | U.S. citizens, residents, and domestic trusts and estates follow the Instructions for Form 8960 to figure and report NII and AGI or MAGI |
| CORP | Corporate partners | Not subject to the NIIT; see Regulations sections 1.1411-1 through -10 |
What code Y covers
Code Y reports information not provided elsewhere on Schedule K-3 (or an attachment) regarding income from CFCs and PFICs whose stock the partnership owns. For CFCs and PFICs that you treat as qualified electing funds (QEFs), what is relevant depends on whether you, the partnership or a lower-tier entity made the election under Regulations section 1.1411-10(g). If the partnership made that election for a CFC and the relevant items are already on Schedule K-3, you will not need code Y to complete Form 8960.
Selling the partnership interest
The instructions also note, in the part on selling or exchanging a partnership interest, that gain or loss from disposing of the interest may be net investment income and subject to the NIIT. Form 8960 and its instructions explain how to figure and report the tax.
Worked example
Omar is a U.S. citizen with a K-1 showing a code Y statement about a PFIC that the partnership owns. He checks whether the information is already in Schedule K-3. If not, he adds the figures to his Form 8960 work using that form’s instructions. Because code Y is a supporting statement and not a ready-made line item, he keeps it with his records and confirms the treatment with his preparer.
More K-1 (Form 1065) pages
Other pages in this set: K-1 (1065) Box 1, K-1 (1065) Box 17, K-1 (1065) Box 18, K-1 (1065) Box 20 Codes A and B, K-1 (1065) Box 20 Code N, K-1 (1065) Box 20 Code V, K-1 (1065) Box 20 Code W, K-1 (1065) Box 20 Code AH, K-1 (1065) Box 20 Code AA, K-1 (1065) Box 20 Code AB. The 1099-R box 7 lookup and W-2 box 12 lookup cover the same kind of question for those forms.
Sources
- Instructions for Schedule K-1 (Form 1065) (2025): Box 20, Other Information, code Y; Sale or Exchange of Partnership Interest (tip on the NIIT). Read November 2, 2026.
IRS page last reviewed April 30, 2026. Tax year 2025 edition. Line numbers are those printed in the 2025 instructions and can change. Names in worked examples are made up.
Frequently asked questions
What is box 20 code Y on a Schedule K-1 (Form 1065)?
Net investment income (NII) information that may help you determine your NIIT under section 1411 and is not reported elsewhere on the K-1 or K-3.
Do I always need code Y for Form 8960?
No. If the partnership made an election for a CFC and the relevant items are reported on Schedule K-3, you will not need code Y to complete Form 8960.
Who pays the NIIT?
U.S. citizens and residents, and domestic trusts and estates, follow the Form 8960 instructions. The K-1 instructions state that corporate partners are not subject to the NIIT.
What are CFCs and PFICs?
Controlled foreign corporations and passive foreign investment companies. Code Y is used for information about them that is not provided elsewhere on Schedule K-3.
Can selling my partnership interest trigger the NIIT?
The instructions say gain or loss from the disposition of a partnership interest may be net investment income and could be subject to the NIIT.
Not tax advice
This page summarizes IRS instructions, mostly written for the people who prepare the form, and is not tax, legal or financial advice. The payer, a CPA or an enrolled agent can confirm what a box or code means for your return. Everything runs in your browser; nothing you enter is sent anywhere.