How to Fill Out Schedule B-1 (Form 1065): 50% Owners, Attribution, and Filing

To fill out Schedule B-1 of Form 1065, you list every entity in Part I and every individual or estate in Part II that owns 50 percent or more of the partnership’s profit, loss, or capital, counting both direct interests and any interests attributed through family members or tiered entities. The schedule attaches to Form 1065 and travels with it; you do not file it on its own. Most of the work is the ownership analysis, not the form itself, because the family and entity attribution rules can push someone across the 50 percent line even when their name is nowhere in the partnership agreement.

Do You Need to File Schedule B-1 at All

Two questions on Schedule B of Form 1065 decide it. Question 2a asks whether any entity (corporation, partnership, trust, tax-exempt organization, or foreign government) owned, directly or indirectly, 50 percent or more of the partnership’s profit, loss, or capital. Question 2b asks the same about any individual or estate.¹ A “Yes” to either question triggers Schedule B-1. Two “No” answers, and you skip it.

The 50 percent test looks at whichever is highest among profit, loss, or capital. A partner who holds 40 percent of profits but 55 percent of capital is over the line. You measure at the maximum point during the tax year, so a partner who held 50 percent for part of the year and then sold down still has to be reported.¹ Whether the partnership made money or lost it that year is irrelevant. The schedule reports control, not results.

Working Out Who Counts as a 50 Percent Owner

Direct ownership alone rarely tells the full story. Under Internal Revenue Code Section 267(c), you combine each owner’s direct percentage with any interest attributed to them through family or through other entities. If the combined figure hits 50 percent, that owner belongs on Schedule B-1.²

Family Attribution

An individual is treated as owning what their spouse, siblings (including half-siblings), ancestors (parents, grandparents), and lineal descendants (children, grandchildren) own in the partnership.² Cousins, aunts, uncles, in-laws, and stepchildren are not covered.

Family attribution only applies when the individual already holds some direct or indirect interest of their own. The Form 1065 instructions give this example: if Person A directly owns 50 percent of Partnership X and Person B (A’s daughter) owns nothing in Partnership X and has no indirect interest through any entity, A’s interest is not attributed to B.³ Person A still hits the threshold on their own and gets listed.

Ownership Through Other Entities

When an interest is held through a corporation, another partnership, a trust, or an estate, you trace the chain and multiply through each layer. The Form 1065 instructions work through this example: Corporation A owns 50 percent of Partnership B, which owns 70 percent of Partnership C. Corporation A also directly owns 15 percent of Partnership C. The indirect interest through Partnership B is 35 percent (50% × 70%), bringing Corporation A’s total in Partnership C to 50 percent and triggering Schedule B-1 for Partnership C.³

The pattern is the same each time. Start with the direct percentage. Calculate each indirect percentage by multiplying through the chain. Add them together. Fifty percent or more, and the owner goes on the schedule.

Completing Part I: Entities

Fill in Part I if you answered “Yes” to Schedule B, Question 2a. At the top of the form, enter the partnership’s name and Employer Identification Number exactly as they appear on Form 1065. Then list each qualifying entity with the following information:¹

The entity’s legal name as registered with the IRS.
The entity’s EIN.
The type of entity: corporation, partnership, trust, tax-exempt organization, or foreign government.
Country of organization.
Maximum percentage of profit, loss, or capital owned at any point during the tax year.

Report the highest of the three percentages, not an average and not the year-end figure.

Completing Part II: Individuals and Estates

Fill in Part II if you answered “Yes” to Schedule B, Question 2b. For each individual or estate that meets the 50 percent test, provide:¹

Full legal name of the individual, or the name of the estate.
Social Security Number for individuals; EIN for estates.
Country of citizenship, for individuals.
Maximum percentage of profit, loss, or capital during the tax year.

If you don’t already have a partner’s taxpayer identification number, Form W-9 collects the legal name, TIN, entity classification, and address in one standard document. Sending W-9 requests to new partners when they’re admitted is easier than chasing them down in March.

The Disregarded Entity Trap

If a partner on the books is a disregarded entity, typically a single-member LLC that has not elected corporate treatment, do not list the LLC on Schedule B-1. List the entity’s owner. If that owner is an individual, they go in Part II, not the LLC in Part I.¹ This look-through catches preparers when the partnership agreement names the LLC but the form requires the person behind it.

Submitting the Schedule With Form 1065

Schedule B-1 is never filed on its own. It goes in with the rest of the Form 1065 package.¹ For electronic filing through the IRS Modernized e-File system, it rides along as a digital attachment. Partnerships with more than 100 partners are generally required to e-file, and any partnership may choose to. For paper filing, staple Schedule B-1 to the back of Form 1065 and mail the full package to the IRS service center that handles your partnership.

Fixing an Error After Filing

If you notice a missing owner, a wrong percentage, or an incorrect TIN after the return has gone in, how you correct it depends on whether the partnership is subject to the centralized audit rules of the Bipartisan Budget Act of 2015. Most partnerships formed after 2017 are. BBA partnerships correct errors through an Administrative Adjustment Request instead of a traditional amended return, using Form 8082 for e-filed returns or Form 1065-X for paper returns, along with a corrected Form 1065 marked “Amended return.” Only the partnership representative or their designated individual can sign the AAR. When adjustments affect individual partners, the partnership furnishes each of them a Form 8986 rather than corrected Schedules K-1 or K-3.⁴

What Happens If You Leave It Off

An incomplete Form 1065, including one missing a required Schedule B-1, exposes the partnership to a penalty under Internal Revenue Code Section 6698. It accrues each month or partial month the return stays incomplete, up to 12 months. The monthly charge is a base amount of $195 (adjusted annually for inflation) multiplied by the number of partners at any time during the year.⁵ A 10-partner partnership at the statutory base rate runs $1,950 per month and up to $23,400 across the full window, and the inflation-adjusted figure is higher.

The penalty can be waived for reasonable cause. Small partnerships with 10 or fewer partners may qualify for automatic relief under Revenue Procedure 84-35, provided every partner is a U.S. individual or an estate, each partner’s share of all partnership items is identical, and every partner reported their share of income, deductions, and credits on a timely filed personal return.⁶

1
Internal Revenue Service. Schedule B-1 (Form 1065) – Information on Partners Owning 50% or More of the Partnership
2
Office of the Law Revision Counsel. 26 U.S. Code 267 – Losses, Expenses, and Interest With Respect to Transactions Between Related Taxpayers
3
Internal Revenue Service. Instructions for Form 1065 U.S. Return of Partnership Income
4
Internal Revenue Service. File an Administrative Adjustment Request for a BBA Partnership
5
Office of the Law Revision Counsel. 26 USC 6698 – Failure to File Partnership Return
6
Internal Revenue Service. Applicability of Revenue Procedure 84-35 to Partnerships