Updated October 16, 2026. Quick answer: Box 1 of Schedule K-1 (Form 1120-S) is a shareholder’s share of the S corporation’s ordinary income or loss from its trade or business activities. The 2025 instructions send it to Schedule E (Form 1040), line 28, and the column depends on whether you materially participated and whether the amount is income or a loss. Basis and at-risk limits are applied to a loss first.
What box 1 reports
On the form, line 1 of Part III is labelled “Ordinary business income (loss)”. The instructions describe it this way: “The amount reported in box 1 is your share of the ordinary income (loss) from trade or business activities of the corporation.” This page covers the shareholder’s side of a K-1 you received; it does not cover how the corporation files its own return. Every other box is set out on the Schedule K-1 (Form 1120-S) boxes overview.
The instructions open with a reminder that the tax follows the income, not the cash. “You may be liable for tax on your share of the corporation’s income, whether or not distributed.” “Include your share on your tax return if a return is required.”
“Your share of S corporation income isn’t self-employment income and it isn’t subject to self-employment tax.”
Where box 1 goes on Form 1040
The starting rule: “Generally, where you report this amount on Form 1040 or 1040-SR depends on whether the amount is from an activity that is a passive activity to you.” The instructions then apply to an “individual shareholder filing a 2025 Form 1040 or 1040-SR”: “find your situation below and report your box 1 income (loss) as instructed after applying the basis and at-risk limitations on losses.”
| Your situation | Where the instructions send it |
|---|---|
| Income or loss from a trade or business in which you materially participated | “Report box 1 income (loss) from corporate trade or business activities in which you materially participated in column (i) or (k) of Schedule E (Form 1040), line 28.” |
| Income from a trade or business in which you did not materially participate | “If income is reported in box 1, report the income in column (h) of Schedule E (Form 1040), line 28.” |
| Loss from a trade or business in which you did not materially participate | “If a loss is reported in box 1, follow the Instructions for Form 8582 to figure how much of the loss can be reported in column (g) of Schedule E (Form 1040), line 28.” |
The landing spot is Schedule E (Form 1040), line 28, and the passive loss worksheet is Form 8582. If the corporation had more than one business, “it will attach a statement identifying the income or loss from each activity.”
Material participation: the seven tests
Everything in the table turns on material participation, so the tests matter. “If you are an individual, you materially participated in an activity only if one or more of the following apply.” Each test is shown below as printed.
| Test | As printed |
|---|---|
| 1 | “You participated in the activity for more than 500 hours during the tax year.” |
| 2 | “Your participation in the activity for the tax year constituted substantially all the participation in the activity of all individuals” |
| 3 | “You participated in the activity for more than 100 hours during the tax year, and your participation in the activity for the tax year wasn’t less than the participation in the activity of any other individual” |
| 4 | “The activity was a significant participation activity for the tax year, and you participated in all significant participation activities” for more than 500 hours during the year |
| 5 | “You materially participated in the activity for any 5 tax years (whether or not consecutive) during the 10 tax years that immediately precede the tax year.” |
| 6 | “The activity was a personal service activity and you materially participated in the activity for any 3 tax years (whether or not consecutive) preceding the tax year.” |
| 7 | “Based on all the facts and circumstances, you participated in the activity on a regular, continuous, and substantial basis during the tax year.” |
“All determinations of material participation are based on your participation during the corporation’s tax year.”
Work that does not count toward participation
Hours count only when they are the right kind of hours. “Generally, any work that you or your spouse does in connection with an activity held through an S corporation (where you own your stock at the time the work is done) is counted toward material participation.” Two exceptions apply. “The work isn’t the type of work that owners of the activity would usually do, and one of the principal purposes of the work that you or your spouse does is to avoid the passive loss or credit limitations.” “You do the work in your capacity as an investor and you aren’t directly involved in the day-to-day operations of the activity.”
The instructions give investor examples that do not count: “Studying and reviewing financial statements or reports on operations of the activity”, “Preparing or compiling summaries or analyses of the finances or operations of the activity for your own use”, and “Monitoring the finances or operations of the activity in a nonmanagerial capacity.”
What a passive result means
If you materially participated, the result is not passive. “Income (loss), deductions, and credits from an activity are nonpassive if you determine that” you materially participated in a trade or business activity of the corporation. If you did not, the amount is passive. “Report passive income (losses), deductions, and credits as follows.” “If you have an overall gain (the excess of income over deductions and losses, including any prior-year unallowed loss) from a passive activity, report the income, deductions, and losses from the activity as indicated in these instructions.”
The limits that apply to a box 1 loss
The instructions list four limits and put them in a fixed order: “These limitations and the order in which you must apply them are as follows: the basis limitations, the at-risk limitations, the passive activity limitations, and the excess business loss limitations.” The amounts printed in Part III are before any of them. “The amounts shown in boxes 1 through 17 reflect your share of income, loss, deductions, credits, and other items from corporate business or rental activities without reference to limitations on losses, credits, or other items that may have to be adjusted”.
The basis step comes first. “Generally, the deduction for your share of aggregate losses and deductions reported on Schedule K-1 is limited to the basis of your stock and loans from you to the corporation.” “Any losses and deductions not allowed this year because of the basis limit can be carried forward indefinitely and deducted in a later year subject to the basis limit for that year.” “You are responsible for keeping the information needed to figure the basis of your stock in the corporation.” The instructions name the worksheet form: “You should generally use Form 7203” “to figure your aggregate stock and debt basis.”
The at-risk step follows basis. “Generally, if you have (a) a loss or other deduction from any activity carried on as a trade or business or for the production of income by the corporation, and (b) amounts in the activity for which you aren’t at risk, you will have to complete Form 6198, At-Risk Limitations, to figure your allowable loss for the activity.” Form 6198 is covered on the Form 6198 page.
After those two steps comes the passive test. “When applicable, the passive activity limitations on losses are applied after the limitations on losses for a shareholder’s basis in stock and debt and the shareholder’s at-risk amount.”
Other Schedule E items and consistency with the corporation
If your Schedule E has items that are not on the K-1, keep them apart. “If you have amounts other than those shown on Schedule K-1 to report on Schedule E (Form 1040), enter each item separately on Schedule E (Form 1040), line 28.”
Owner pay is a separate subject from box 1. The reasoning behind how an S corporation owner is paid is covered on the S corporation salary page.
Which revision applies
The edition read for this page is the 2025 Shareholder’s Instructions for Schedule K-1 (Form 1120-S) and the 2025 Schedule K-1 (Form 1120-S) itself, which are the revisions irs.gov served when they were read on 2026-10-16. Check the revision printed on the Schedule K-1 you received and the matching instructions, because a later edition can change the box layout, the column letters and the reporting lines.
Common mistakes
- Putting every box 1 amount in one Schedule E column. The instructions send a participated amount to column (i) or (k), passive income to column (h) and a passive loss through Form 8582 toward column (g).
- Treating a loss as deductible because it is printed in box 1. The instructions say to report box 1 after applying the basis and at-risk limitations on losses, and the passive limits come after those two.
- Counting investor-style hours as participation. The instructions say studying financial statements, preparing summaries for your own use and monitoring the activity in a nonmanagerial capacity do not count toward material participation.
Related: Schedule E (Form 1040), Form 8582 passive activity loss limits, Form 6198 at-risk limits, S corporation salary and part-time business, and Schedule K-1 (Form 1065) boxes explained.
Sources
- 2025 Shareholder’s Instructions for Schedule K-1 (Form 1120-S): https://www.irs.gov/pub/irs-pdf/i1120ssk.pdf
- Schedule K-1 (Form 1120-S) (2025), Shareholder’s Share of Income, Deductions, Credits, etc.: https://www.irs.gov/pub/irs-pdf/f1120ssk.pdf
Read from the IRS documents linked above on October 16, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.