U.S. · Tax forms
K-1 box 20 code A and B.
Investment income and investment expenses, and how they reach Form 4952.
Box 20, code A is your share of the partnership’s investment income and goes on Form 4952, Part II, line 4a. Code B is your share of investment expenses and goes on Form 4952, Part II, line 5. They work with box 13 code H (investment interest expense, Form 4952 line 1) to figure how much investment interest you can deduct.
Look up a Form 4952 input
Result
Where the investment codes go
| Code | Meaning | Where it goes (per the IRS instructions) |
|---|---|---|
| 20-A | Box 20, code A: Investment income | Form 4952, Part II, line 4a |
| 20-B | Box 20, code B: Investment expenses | Form 4952, Part II, line 5 |
| 13-H | Box 13, code H: Investment interest expense | Form 4952, line 1 |
What these codes are for
If the partnership has investment income or other investment expense, it reports your share in box 20 using codes A and B. The investment interest expense itself is in box 13, code H. The instructions say to include investment income and expenses from other sources as well to figure how much of your total investment interest is deductible, and that interest the partnership paid or accrued on debts allocable to investment property can be limited. The deduction itself is worked out on Form 4952, which this page does not reproduce.
Each code has its own rule
Box 20 holds many unrelated items, and each code has its own instruction. Codes A and B feed Form 4952. Other codes, such as N, are for information only. Always follow the instruction for the specific code.
Worked example
Elena has $1,200 in box 20 code A, $300 in code B and $500 in box 13 code H. She enters $500 on Form 4952 line 1, $1,200 on Part II line 4a and $300 on line 5, then adds investment income and expenses from her brokerage accounts on the same lines before working through the rest of the form.
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 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 Y, 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, codes A and B; Box 13, code H, Investment interest expense. 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 A on a Schedule K-1 (Form 1065)?
Your share of the partnership’s investment income. Report it on Form 4952, Part II, line 4a.
What is box 20 code B?
Your share of the partnership’s investment expenses. Report it on Form 4952, Part II, line 5.
Where does investment interest expense appear?
In box 13, code H, and it goes on Form 4952, line 1.
Do I add my other investment income to the K-1 amounts?
Yes. The instructions say to include investment income and expenses from other sources to figure how much of your total investment interest is deductible.
Is box 20 code A the same as interest and dividends in boxes 5 and 6?
No. Interest and dividends have their own boxes (5 and 6a). Code A is a separate entry in box 20 that the instructions send to Form 4952, Part II, line 4a.
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.