Schedule B-1 of Form 1065: Disclosing 50% Owners in Tiered Partnerships, Family LLCs, and Private Equity Funds

If you file a Form 1065 partnership return, there is a one-page schedule that quietly drives more IRS examination notices than almost any other partnership disclosure. It does not calculate a single dollar of tax. It does not change anyone's allocation. All it does is name names — and the people the IRS most wants named are often the people partnerships forget to list.

That schedule is Schedule B-1, Information on Partners Owning 50% or More of the Partnership. It looks simple. It is not. The trap is that "owning 50%" is not what most filers think it means, and the attribution rules that decide who crosses the threshold are not the ones every accountant has memorized from corporate tax class. Get this disclosure wrong on a tiered partnership, a family LLC, or a fund-of-funds structure, and the return is incomplete on its face — which is exactly the kind of red flag the IRS uses to triage which partnership returns to examine.

This guide walks through who must file, who counts as a 50% owner once attribution is layered on, the structures that trip filers up most often, and how to keep your records clean enough that next year's Schedule B-1 takes ten minutes instead of ten days.

What Schedule B-1 Actually Reports

Schedule B-1 is the partnership world's answer to a deceptively simple question: who really owns this entity?

Form 1065's main Schedule B contains two questions that gate the entire filing. They sit in the "Other Information" section, currently numbered 2a and 2b (the IRS renumbered these from 3a and 3b a few years ago, which is one reason old templates and stale checklists still ask the wrong question number):

Question 2a asks whether any entity — corporation, partnership, trust, tax-exempt organization, or foreign government — owns, directly or indirectly, 50% or more of the partnership's profit, loss, or capital.
Question 2b asks the same question about any individual or estate.

If the answer to either is yes, the partnership must attach Schedule B-1. Part I lists qualifying entities. Part II lists qualifying individuals and estates. For each owner, you disclose:

Name
Taxpayer identification number (EIN or SSN)
Country of organization or citizenship
The maximum percentage owned in profit, loss, or capital

That last column is doing more work than it looks. You report the highest of the three percentages — profit, loss, or capital — measured at year-end. A partner who is allocated 30% of profit but holds 60% of capital is a 60% owner for Schedule B-1 purposes, and must be disclosed.

The 50% Test Is Three Tests in Disguise

The most common filing error is treating "50% or more" as a single number. It is not. A partner clears the threshold if they hit 50% in any of:

Profit
Loss
Capital

This matters because real partnerships rarely allocate all three identically. A managing partner with a 20% capital account might receive 60% of profits through a carried interest. A retiring partner might have 80% of capital but be allocated zero profit going forward. Both cross the 50% threshold on at least one axis, and both belong on Schedule B-1.

The threshold is measured at the end of the tax year, but a midyear surge above 50% can still pull a partner onto the schedule if the year-end measurement reflects it. Buy-ins, redemptions, and admission of new partners all need a clean closing-day ownership table. If your books only track ownership at the date of cash movement, you do not have the data Schedule B-1 demands.

Section 267(c), Not Section 318 — The Attribution Rule Most Filers Get Wrong

Here is the technical point that catches even experienced preparers. Schedule B-1 uses the constructive ownership rules of Internal Revenue Code Section 267(c) to determine indirect ownership — not Section 318.

That distinction is more than academic. Section 318, which most tax professionals first encounter in the context of S corporation distributions and corporate stock redemptions, has a specific shape: a defined family group, partnership-to-partner attribution, option attribution, and a 50% threshold for corporate attribution. Section 267(c) is a different animal:

Family attribution under 267(c)(4) sweeps in a wider family group than Section 318. The "family" of an individual under 267(c) includes brothers and sisters (whole or half blood), spouse, ancestors (parents, grandparents, and beyond), and lineal descendants (children, grandchildren, great-grandchildren, etc.). Section 318's family group is narrower — it stops at parents in the ancestor direction and excludes siblings.
Entity attribution under 267(c)(1) flows proportionately from corporations, partnerships, estates, and trusts to their owners. There is no 50% threshold to trigger attribution, unlike Section 318(a)(2)(C).
The partnership instructions specifically exclude Section 267(c)(3) — the "partner-to-partner" rule that would treat every partner as constructively owning what every other partner owns. Without that exclusion, almost every two-partner partnership would have to disclose both partners as 100% owners, which is not the intent.

If you build a Schedule B-1 model on the assumption that the rules are the same as a Section 318 stock-attribution chart, you will under-report on family holdings and over-report inside multi-tier partnership chains. Both are mistakes the IRS notices.

What the family attribution rule actually does

Important wrinkle: family attribution under 267(c) only operates if the attributed party already has some direct or indirect interest in the partnership. A daughter who owns nothing in her mother's partnership is not pulled in just because her mother is a partner. But a daughter who owns 10% directly will be deemed to own her mother's interest too — and if mom holds 45%, the daughter now sits at 55% and must be disclosed.

This rule cuts both ways. It can pull a small partner over the line by aggregating their interest with a parent or spouse. It can also confirm that an in-law has no reportable interest at all, because in-laws are not in the 267(c) family group.

How entity attribution stacks in tiered structures

Entity attribution is proportionate, which means it scales cleanly through tiers. Consider:

Fund I LP
  └─ owns 60% of LowerTier LP
       └─ which owns 40% of OperatingCo Partnership

OperatingCo's Schedule B-1 must look up the chain. Fund I is deemed to own its proportionate share of LowerTier's stake in OperatingCo: 60% × 40% = 24%. That alone does not clear 50%. But if Fund I also holds a separate 30% direct interest in OperatingCo, its combined ownership is 24% + 30% = 54%, and Fund I must be listed on Part I.

This is where tiered partnerships routinely fail their own disclosure. The lower-tier preparer sees a 30% direct partner and assumes the question is settled. The upper-tier partner's indirect stake through intermediate vehicles never gets aggregated. The schedule comes out understated, and the rest of the return — including K-2 and K-3 reporting on foreign partners — inherits the same gap.

The Three Structures That Cause the Most Schedule B-1 Errors

1. Family holding LLCs

Family limited liability companies and partnerships are designed around estate-planning attribution: gifts to children, grandchildren's trusts, GRATs, and spouses splitting capital interests. The economic story is one family unit; the K-1s are a half-dozen separate names, each below 50%.

Schedule B-1 will often pull all of them above 50% once 267(c) attribution is applied. A grandfather who directly owns 35%, with his spouse holding 10% and a son holding 8%, is constructively a 53% owner for disclosure purposes — assuming the spouse and son qualify under the "must have some direct or indirect interest" gate. The son becomes a 53% owner too, on the same logic. Both belong on Part II, and the family typically lists every adult member who is in the 267(c) group and has any direct stake.

A clean family-holding-LLC checklist looks like this:

Build a one-page family tree showing every relative who holds any direct or indirect interest.
Annotate each person's direct percentage in profit, loss, and capital separately.
Apply 267(c)(4) attribution to layer family interests onto each direct holder.
Re-test the 50% threshold against the three economic measures.
List every individual who clears it, including those whose direct percentage alone is small.

2. Private equity funds and blocker structures

Sponsor-led funds with carried-interest GPs, parallel funds for taxable and tax-exempt LPs, and Cayman or Delaware blocker corporations are the second category. Two patterns to watch:

Carry-allocation partners. A GP entity with a tiny capital account but a 20% profits interest can blow through the 50% test if the fund has very few LPs or if the GP holds carry across both the main and parallel funds. Always re-check the GP's allocation in profit, not just capital.

Blocker corporations as 50%+ owners. When a U.S. blocker C-corp sits between foreign LPs and a U.S. operating partnership, the blocker may itself be a 50%-plus partner. It belongs on Part I as a corporation, and its existence does not exempt the partnership from disclosure even though it shields the foreign investors from a Schedule K-1.

A practical tell: if your fund has fewer than ten partners and any one of them is a related entity controlled by the sponsor, you almost certainly have a Schedule B-1 disclosure. Fund-of-funds and master-feeder structures should treat Schedule B-1 as mandatory until proven otherwise — the default assumption being disclosure, not exemption.

3. Tiered partnerships with disregarded entity layers

Single-member LLCs are disregarded for federal tax purposes. They are also the most common source of incorrect Schedule B-1 reporting.

The rule: do not list a disregarded entity as the owner. List the disregarded entity's regarded owner — the individual, corporation, or partnership that owns the SMLLC. If the disregarded entity's owner is an individual, they go in Part II, not Part I.

Filers who carry over the K-1 partner list directly to Schedule B-1 routinely get this backwards: they list "ABC Holdings LLC, EIN xx-xxxxxxx, 60% owner" in Part I, when "ABC Holdings LLC" is a disregarded SMLLC whose sole member is Jane Smith, an individual. The correct entry puts Jane Smith in Part II with the same percentage.

The same logic chains through multiple disregarded layers — keep looking up the ownership chain until you reach an entity or person that is not disregarded, and that is your Schedule B-1 reportable owner.

Common Mistakes That Show Up on Examined Returns

A handful of recurring errors account for most Schedule B-1 audit findings:

Listing the same owner twice — once in Part I and once in Part II, because the partner is held by both a controlled entity and the individual directly. Aggregate first, list once at the maximum constructive percentage.
Defaulting country to "United States" for a foreign individual or foreign corporation because the country field was left blank in the underlying partner record. This is one of the easier discrepancies for an examiner to spot when cross-referencing against Forms 8804/8805 or K-2/K-3.
Forgetting the year-end test. A partner who held 80% on June 30 but was redeemed down to 5% by December 31 is not a 50%-or-more owner for that year-end measurement. A partner admitted on December 30 at 51% is.
Reporting a disregarded entity instead of its regarded owner. Software defaults often pull the partner record directly without traversing the ownership chain.
Creating "shadow" partner records in the prep software to make percentages tie to 100%. Schedule B-1 percentages can legitimately sum to more than 100% because the same economic interest can be attributed to multiple constructive owners. Adjusting the underlying K-1 percentages to force a sum of 100% creates a return that no longer ties to the actual partnership agreement — and the K-1 mismatch is itself an examination flag.
Mixing up Section 267(c) and Section 318. Most preparation software defaults to one set of attribution rules; verify which one is being applied and override if needed.

What Happens If You Get It Wrong

Schedule B-1 itself does not have a stand-alone penalty. The exposure is indirect — and usually worse than a flat fine:

An incomplete Schedule B-1 makes the underlying Form 1065 itself incomplete, which can suspend the protection of the statute of limitations on assessment and open the return to examination for longer than the usual three-year window.
Inconsistencies between Schedule B-1 and other partner-level disclosures (Schedule K-1, K-2, K-3, Forms 8804/8805 for foreign partners, Form 5471 ownership chains) are exactly the kind of mismatch the IRS uses as a partnership audit selection input.
For BBA-regime partnerships, examination of the partnership return puts every partner downstream of a potential imputed underpayment. A small disclosure error can balloon into a partnership-level tax liability that requires either a push-out election or full partnership payment.
If the partnership is also a withholding agent — say, for foreign partners under Section 1446 — the Schedule B-1 disclosure may be cross-checked against withholding compliance. Misidentifying a foreign partner as domestic, or vice versa, can compound into a withholding tax adjustment plus penalties and interest.

The fix is rarely difficult; the cost of not fixing it is what hurts.

Building the Records You Need Before Filing

A Schedule B-1 disclosure is only as accurate as the ownership ledger behind it. Most preparation pain comes from reconstructing percentages and constructive ownership relationships during the filing crunch, weeks after the events that changed them. A few habits eliminate the scramble:

Maintain a year-round capital and ownership ledger with three columns per partner: profit, loss, and capital percentages. Update on every admission, redemption, transfer, or amended partnership agreement — not at year-end.
Document family relationships for every individual partner whose family group could plausibly cross 50%. A short relationship map kept with the partnership records is faster than rebuilding it under deadline pressure.
Track disregarded-entity owners at the time the partner is admitted. Record the regarded owner alongside the SMLLC name so future filings do not have to chase the chain.
Reconcile Schedule B-1 with K-1 percentages each year, and document any intentional differences (typically arising from attribution). A short memo in the workpapers explaining why a Part II individual at 53% does not match any single K-1 will save hours of explanation in a future examination.

The clearer the underlying records, the smaller the Schedule B-1 question becomes. It stops being a once-a-year guessing game and turns into a five-line lookup.

Keep Your Partnership Books Audit-Ready From Day One

Accurate Schedule B-1 reporting starts with clean, transparent partner-level records — capital accounts, profit and loss allocations, transfers, and ownership history all reconciled to the partnership agreement and traceable across years. The partnerships that file this schedule painlessly are the ones whose books were built to surface this information, not the ones who reconstruct it every March.

Beancount.io gives you plain-text accounting that is fully version-controlled, queryable, and transparent — every change to a capital account is a tracked, auditable transaction, and every prior year's ownership ledger is permanently available exactly as it was filed. No black boxes, no proprietary database, no vendor lock-in. Get started for free and see why developers, finance professionals, and serious partnerships are switching to plain-text accounting for the records that matter most.