Introduction
If you searched for "Form 1120 Schedule B" expecting a catch-all list of corporate disclosures, you've probably landed on the wrong schedule. Many business owners, and even some bookkeepers, assume Schedule B covers everything from ownership stakes to 1099 payments.
It doesn't.
Schedule B (Form 1120) is officially titled Additional Information for Schedule M-3 Filers, and it only applies to a specific group of corporations.
The broader "Other Information" disclosures most filers need sit on Schedule K (Form 1120) instead. Those cover accounting method, ownership, foreign activity and digital assets.
This guide is for C corporations filing Form 1120. It does not cover S corporations using Schedule B (Form 1120-S), or individuals using Schedule B with Form 1040 for interest and dividend reporting.
We'll cover who needs Schedule B, how it connects to Schedule K and Schedule G, what records to pull together, and how to file it correctly for the 2026 tax year.
Key Takeaways
- Schedule B (Form 1120) applies only to corporations required to file Schedule M-3, not every Form 1120 filer
- Ownership, 1099, foreign-owner and digital-asset questions actually live on Schedule K, not Schedule B
- Confirm every line number, threshold and mailing detail against the official 2026 IRS release before filing
- Australian-owned US corporations should reconcile Schedule G ownership percentages against group accounting records before sign-off
What Is Schedule B (Form 1120)?
Schedule B attaches to Form 1120 and asks a short list of questions that supplement Schedule M-3, the detailed book-to-tax reconciliation schedule for larger corporations. It doesn't add new income or deduction categories. It fills in gaps that M-3 doesn't directly capture.
Per the Schedule B instructions, the form asks about:
- Whether partnership allocations to the corporation are disproportionate to its capital contribution or profit-sharing ratio
- Sales or transfers of intangible-asset interests to or from a related party
- Related-party foreign cost-sharing arrangements where no Form 5471 was filed
- Changes in financial-accounting principles versus changes in US tax accounting methods
- VEBA trusts, indirect-cost allocation for self-constructed assets, and nonshareholder capital contributions
That's a narrow, technical list, a far cry from the broad "ownership, elections, foreign activity" coverage many guides describe.
Schedule B vs Schedule K: Where the Confusion Comes From
The schedule most people actually mean when they say "Form 1120 other information" is Schedule K, officially titled "Other Information." It covers accounting method, ownership interests, 1099 reporting, publicly offered debt, section 163(j), qualified opportunity funds and digital assets. These two schedules sit a few pages apart in the same return, which is likely why they get mixed up so often.
Comparing the Three "Schedule B" Forms
| Form | What it covers | Who files it |
|---|---|---|
| Schedule B (Form 1120) | Additional disclosures for Schedule M-3 filers | C corporations meeting the M-3 asset test |
| Schedule B (Form 1120-S) | "Other Information" for S corporations | S corporations |
| Schedule B (Form 1040) | Interest, dividends, and foreign account/trust questions | Individual taxpayers |
If your business is a C corporation, you need the first one, plus Schedule K, not the S corporation version.
Who Must Complete Schedule B and When?
Not every Form 1120 filer touches Schedule B. Whether it applies depends almost entirely on whether the corporation files Schedule M-3.
The Schedule M-3 Trigger
A domestic corporation, or consolidated group, generally must file Schedule M-3 instead of Schedule M-1 once year-end total assets reach $10 million, according to the Schedule M-3 instructions. Below that threshold, most corporations skip M-3 entirely, and Schedule B never comes into play.
There's a second filter specific to Schedule B itself:
- Corporations filing Schedule M-3 with year-end assets under $50 million don't need to file Schedule B
- Corporations filing Schedule M-3 voluntarily, without being required to, also skip Schedule B
- Consolidated groups file one Schedule B for the whole group, submitted by the parent
A corporation can be large enough to trigger M-3 and still be exempt from Schedule B if it sits between $10 million and $50 million in assets.
Deadlines and Extensions
Form 1120, and Schedule B with it, is generally due the 15th day of the fourth month after the tax year ends. Corporations with a June 30 fiscal year-end use the third month instead. If that date falls on a weekend or legal holiday, it moves to the next business day.
Need more time? File Form 7004 by the original due date. Per the Form 7004 instructions, most C corporations get an automatic six-month extension, though some June 30 year-ends still qualify for seven months. Either way, the extension covers filing only. Any tax owed is still due on the original deadline.
Quick checklist before you start:
- Confirm the entity files Form 1120, not 1120-S or 1065
- Identify the exact tax year and whether it's calendar or fiscal
- Pull the current 2026 form version, not a prior year's copy
- Check assets against the $10 million and $50 million tests
- Review every Schedule B and Schedule K question before deciding what to attach
How to Complete Schedule B (and Schedule K) for 2026
Always pull the official 2026 Schedule B and Form 1120 package before you start. Line numbers, thresholds and attachment rules shift between tax years, and working from last year's PDF is one of the fastest ways to misfile.
Schedule B's Own Questions
Expect questions covering:
- Disproportionate partnership allocations relative to the corporation's capital or profit-sharing ratio
- Related-party transfers of intangible assets
- Foreign cost-sharing arrangements tied to related parties
- Accounting-principle changes (financial statements) versus accounting-method changes (tax return)
- VEBA trust involvement, self-constructed asset cost allocation, and capital-contribution characterisation
Each of these needs to tie back to your books. If your accountant changed a depreciation method mid-year, that same change should appear consistently on Schedule B, the financial statements and Schedule M-3.
Schedule K Items Most Filers Actually Need
Most ownership, election and disclosure items sit on Schedule K:
- Accounting method - cash, accrual, or other; must match the method used throughout the return
- Ownership of the corporation - 20%+ direct, or 50%+ direct or indirect, owners require Schedule G (not Form 1120-S "Schedule B-1")
- The corporation's interests in other entities - similar tests for stock, partnership interests and trust beneficial interests
- Foreign ownership - one foreign person owning 25% or more of voting power or stock value
- 1099 reporting - whether payments required Forms 1099 and whether those forms were filed
- Section 163(j), qualified opportunity funds, digital assets - each with its own attachment
A Quick Worked Example
Say a corporation holds a 40% interest in a partnership, but depreciation deductions are allocated 90% to the corporation while every other item splits 40/60. That mismatch is disproportionate to its capital ratio, so Schedule B gets a "Yes," with an explanation attached.
Separately, if that same corporation paid a contractor above the 1099-NEC reporting threshold during the year, Schedule K's 1099 question also needs a "Yes," supported by the filed form. Every "Yes" answer points to a specific attachment. Treat the checkbox as a signpost, not the finish line.
Records, Common Errors, and Filing Checklist
Gather These Records First
- General ledger and trial balance
- Accounting-method documentation and any change-of-method filings
- Ownership registers, organisational charts, and shareholder lists
- Entity agreements for partnerships, trusts or disregarded entities
- Foreign-activity records, including related-party cost-sharing agreements
- 1099 files and vendor payment records
Errors We See Most Often
- Using the Form 1120-S version of Schedule B by mistake
- Working from last year's line numbers instead of the current release
- Missing indirect or constructive ownership under attribution rules
- Treating "Schedule B-1" as the Form 1120 ownership attachment, when it's actually Schedule G
- Answering based on today's ownership structure rather than the tax year's facts
Before signing, reconcile accounting method and ownership figures against the balance sheet and Schedule L. Confirm every "Yes" answer has supporting documentation, and check that required attachments such as Schedule G or Form 8990 are in the filing package.
For Australian-owned US corporations: keep entity names and ownership percentages consistent between your US filing and your Australian accounting records. Where transfer pricing, withholding or treaty questions overlap with US corporate reporting, a second review is worthwhile.
VJM Global supports Australian and other multinational businesses with bookkeeping, cross-border compliance coordination, and review of corporate filing information. That includes Section 92 transfer-pricing certification work for groups that also have Indian operations.
Before you file, confirm:
- Correct 2026 form version and tax period
- Accurate EIN and entity details
- Signatures from an authorised officer
- All required attachments included
- Payment arrangements for any tax due, plus retained copies
Filing Schedule B With Form 1120
Schedule B isn't submitted on its own. It goes in as part of the complete Form 1120 return, attached in the order the instructions specify, alongside Schedule K, Schedule G and any other required schedules.
E-Filing vs Paper Filing
Electronic filing gives you instant confirmation of receipt and faster processing. Many mid-size and larger corporations must e-file once they cross certain return-volume thresholds. Check the current IRS rules against your corporation's total filing volume for the year, not just its income tax returns.
If you're filing on paper, the correct IRS service centre depends on your business location, year-end assets, and whether Schedule M-3 applies. Don't guess. Check the official address locator for the current tax year before mailing anything.
An extension via Form 7004 covers the filing deadline, not the accuracy of what's inside Schedule B and Schedule K. Those still need to be completed correctly, extension or not.
Need help pulling this together? VJM Global's US tax team prepares Form 1120, 1120-S and 1065 returns, and works daily in Lacerte, ProSeries and UltraTax.
If you're an Australian business with a US subsidiary and want a second review of your Schedule B and Schedule K answers before filing, contact VJM Global for a professional review.
Frequently Asked Questions
Who needs to complete Schedule B for Form 1120?
Only corporations required to file Schedule M-3 with year-end total assets of $50 million or more generally need Schedule B. Smaller filers and those filing M-3 voluntarily are exempt.
What is Schedule B on Form 1120 and what information does it include?
Schedule B is titled Additional Information for Schedule M-3 Filers. It covers disproportionate partnership allocations, related-party intangible transfers, accounting method and principle changes, and other M-3-related disclosures.
When must Schedule B be filed or attached to Form 1120?
File it with Form 1120 by the corporation’s due date, generally the 15th day of the fourth month after year-end, or by the extended deadline if Form 7004 was filed on time.
Where do I mail Form 1120 and Schedule B?
The correct IRS service centre depends on your location, assets and Schedule M-3 status, so check the current IRS address locator before mailing. E-filers don't mail anything.
Is Schedule B for Form 1120 the same as Schedule B for Form 1120-S?
No. They're different schedules for different return types. A C corporation filing Form 1120 uses the Form 1120 version, not the S corporation "Other Information" schedule.
What records are needed to complete Schedule B?
You'll need your general ledger, accounting-method documentation, ownership and partnership agreements, and prior-year returns. Any related-party or foreign cost-sharing agreements should also be on hand.
