K-1 box 13 codes: other deductions on Schedule K-1 (Form 1065)
K-1 box 13 codes are the letter codes a partnership uses on Schedule K-1 (Form 1065) to report a partner's share of other deductions, such as charitable contributions (codes A to G), investment interest expense (code H) and excess business interest expense (code K). Each code goes to a different form and line.
“The partnership will give you a statement that shows charitable contributions subject to the 100%, 60%, 50%, 30%, and 20% AGI limitations.” IRS, Partner’s Instructions for Schedule K-1 (Form 1065) (2025)
What does K-1 box 13 report?
K-1 box 13 reports the partner's share of deductions that the partnership doesn't net into ordinary business income, because each one is limited or reported differently at the partner level. According to the Partner's Instructions for Schedule K-1 (Form 1065) (2025), the partnership identifies each deduction with a letter code from A to AE, plus ZZ for other items, and attaches a statement where more detail is needed.
The codes fall into a few groups. Codes A to G are charitable contributions sorted by AGI limitation, codes H, AC and AD are interest expense that depends on how the money was used, code K is excess business interest expense under section 163(j), and the rest cover items such as medical insurance, retirement contributions and section 743(b) adjustments. For 2025, code X adds qualified sound recording production expenses (P.L. 119-21). Box 13 deductions are among the loss and deduction items in Part II of the partner basis worksheet (lines 15j to 15p), so basis is checked before they reach the return.
Where does each box 13 code go?
Each 2025 box 13 code goes to a specific line of an individual partner's return, according to the code-by-code instructions in the 2025 partner's instructions. The table lists every code, including reserved ones, so a reviewer can match a code on a K-1 to its destination.
| Code | Meaning (2025) | Where it goes |
|---|---|---|
| A | Cash contributions (60%) | Schedule A, line 11 |
| B | Cash contributions (30%) | Schedule A, line 11 |
| C | Noncash contributions (50%) | Schedule A, line 12; partnership's Form 8283 if over $500 |
| D | Noncash contributions (30%) | Schedule A, line 12 |
| E | Capital gain property to a 50% organization (30%) | Schedule A, line 12 |
| F | Capital gain property (20%) | Schedule A, line 12 |
| G | Contributions (100%) | Schedule A, line 12 |
| H | Investment interest expense | Form 4952, line 1 |
| I | Deductions, royalty income | Schedule E, line 19 |
| J | Section 59(e)(2) expenditures | Schedule E, line 28, or amortized via Form 4562 |
| K | Excess business interest expense (EBIE) | Form 8990; reduces basis |
| L | Deductions, portfolio income (other) | Schedule A, line 16 |
| M | Amounts paid for medical insurance | Schedule 1, line 17, or Schedule A, line 1 |
| N | Educational assistance benefits | Schedule E, line 28, separate row |
| O | Dependent care benefits | Form 2441, Part III |
| P | Preproductive period expenses | Deduct or capitalize under section 263A |
| Q | Reserved for future use | None |
| R | Pensions and IRAs | Schedule 1, line 20 (IRA) or line 16 (SEP, SIMPLE, qualified plan) |
| S | Reforestation expense deduction | Schedule E, line 28, column (i), or (g) via Form 8582 |
| T and U | Reserved for future use | None |
| V | Section 743(b) negative income adjustments | With the item adjusted, for example Schedule E, line 28 |
| W | Soil and water conservation | Schedule F, line 12 |
| X | Qualified film, television, theatrical, and sound recording production expenses | Schedule E, line 28, column (i), or (g) via Form 8582 |
| Y | Expenditures for removal of barriers | Section 190, up to $15,000 a year from all sources |
| Z | Itemized deductions | Schedule A, per the statement |
| AA | Contributions to a capital construction fund (CCF) | Subtracted from Form 1040, line 15, marked CCF |
| AB | Penalty on early withdrawal of savings | Schedule 1, Part II, line 18 |
| AC | Interest expense allocated to debt-financed distributions | Schedule E line 28, Form 4952 or nondeductible, by use of proceeds |
| AD | Interest expense on working interest in oil or gas | Form 4952, or Schedule E, line 28, column (i) |
| AE | Deductions, portfolio income | Not deductible by individuals |
| AF to AJ | Reserved for future use | None |
| ZZ | Other | Per the statement |
The charitable codes go on Schedule A with the AGI limit shown in the code name, and the instructions point to Worksheet 2 in Pub. 526 when contributions fall under more than one limit. Charitable contributions, code I royalty deductions and code L portfolio deductions aren't taken into account in figuring the passive activity loss, so they stay off Form 8582. For code C, the partnership gives the partner a copy of its Form 8283 when a noncash item or group of similar items exceeds $500, and the partner completes their own Form 8283 using that information.
Which box 13 deductions are limited at the partner level?
Most box 13 deductions are limited at the partner level, which is why the partnership reports them separately.
Charitable contributions are subject to the partner's own AGI limits on Schedule A, and since 2018 the partner's share of contributions is also subject to the section 704(d) basis limit. Box 20, code AH carries the noncash detail (see box 20 codes). Investment interest expense under code H is deductible only up to net investment income on Form 4952, using box 20 codes A and B plus investment items from other sources. Excess business interest expense under code K isn't deductible this year, but it still reduces basis (not below zero) and unused EBIE is added back to basis just before a disposition. Code AC interest follows the use of the distributed debt proceeds: Schedule E for a business, Form 4952 for an investment, and generally nondeductible for personal use. Code AE isn't deductible by individuals at all. Form 8990 covers the section 163(j) side of code K.
What does a box 13 investment interest calculation look like?
For example, Sam's 2025 K-1 shows $3,000 of investment interest expense in box 13, code H, $2,000 of investment income in box 20, code A and nothing in box 20, code B. Sam has no other investment income, no qualified dividends or net gain from investment property, and no disallowed investment interest from 2024. Sam itemizes deductions.
| Step | Form 4952 line | Amount |
|---|---|---|
| Investment interest expense (box 13, code H) | 1 | $3,000 |
| Total investment interest expense | 3 | $3,000 |
| Investment income (box 20, code A) | 4a | $2,000 |
| Investment income | 4h | $2,000 |
| Investment expenses (box 20, code B) | 5 | $0 |
| Net investment income | 6 | $2,000 |
| Carried forward to 2026 | 7 | $1,000 |
| Investment interest expense deduction | 8 | $2,000 |
Sam deducts $2,000 of the $3,000 as investment interest on Schedule A. The other $1,000 carries forward on line 7 and comes back on the 2026 Form 4952, line 2, which asks for the disallowed amount from the 2025 Form 4952, line 7. If Sam elected to treat qualified dividends as investment income on line 4g, more of the interest would be deductible this year, at the cost of the lower qualified dividend rate on that amount.
What do reviewers check on K-1 box 13?
A reviewer checking K-1 box 13 confirms six items, each tied to the 2025 partner's instructions. The box 13 statement comes first, because it splits charitable contributions by AGI limit and identifies the use of debt proceeds for code AC. The prior-year Form 4952 and Form 8990 come second, because disallowed investment interest and excess business interest expense both carry forward. The basis worksheet comes third, because box 13 deductions sit in Part II of it, and some, such as EBIE, reduce basis even when the deduction itself is deferred on the partner's return. The reviewer also compares box 13 codes against last year's K-1 from the same partnership: a code that moved, such as portfolio deductions appearing under code AE instead of code L, changes whether an individual partner can deduct the amount at all.
Every line checked against the documents the client sent
Filed reads the partner's K-1, the box 13 statement and the prior-year Form 4952 and Form 8990, then checks every line each box 13 code feeds against them. Anything that doesn't tie comes back as a review item with a citation to the source.
Book a demoSchedule A line 16 includes $4,750 from this partnership, matching box 13 code AE on the K-1. Code AE isn't deductible by individuals. Confirm whether the partnership meant code L or the deduction should come off.
Common questions
Where do K-1 box 13 code A contributions go?
K-1 box 13 code A cash contributions go on Schedule A (Form 1040), line 11, subject to the 60% AGI limitation, according to the 2025 partner's instructions. Code B cash contributions also go on line 11 under the 30% limit, while noncash and capital gain property codes C through G go on line 12.
Can an individual deduct K-1 box 13 code AE?
An individual can't deduct K-1 box 13 code AE. The 2025 partner's instructions say these portfolio deductions were formerly deductible by individuals subject to the 2% AGI floor, and now only taxpayers other than individuals deduct amounts clearly and directly allocable to portfolio income. Code L portfolio deductions are a separate code.
What is K-1 box 13 code K?
K-1 box 13 code K is excess business interest expense (EBIE) under section 163(j). A partner who receives code K must file Form 8990. The EBIE reduces outside basis in the year allocated, even though it isn't deductible yet, and any unused amount is added back to basis immediately before the partner disposes of the interest.