Form 851 Instructions: Affiliations Schedule and Member Changes

Form 851, the Affiliations Schedule, is the attachment the common parent of an affiliated group files with its consolidated Form 1120 each year to identify every corporation in the group, allocate estimated tax payments and credits among them, and demonstrate that each subsidiary meets the 80% ownership test.¹ The form has four parts, and the details on ownership percentages and mid-year changes carry more weight than they do on most schedules because errors can undermine the consolidated return itself.

Who Files Form 851 and When

The common parent files Form 851 every year the group files a consolidated return, and attaches it directly to Form 1120. There is no exemption for a year in which the group structure did not change.²

The deadline follows the consolidated return: the 15th day of the fourth month after the tax year ends, which is April 15 for calendar-year filers.³ An automatic six-month extension is available by filing Form 7004 before the original due date.⁴ An authorized officer of the parent signs the consolidated return, and that signature covers the attached Form 851.²

Filing a consolidated return is a privilege, not a requirement. Every corporation that was a group member at any point during the year must consent to the consolidated return regulations, and filing the consolidated return itself counts as consent.⁵ For a subsidiary’s first year in the group, the parent also attaches a Form 1122 as that subsidiary’s formal authorization to be included.⁶

Which Subsidiaries Belong on the Form

An affiliated group is one or more chains of corporations connected through stock ownership with a common parent, satisfying a two-pronged 80% test at each link: the parent or another member must own stock representing at least 80% of the total voting power and at least 80% of the total stock value of each subsidiary.⁷ The parent must clear the 80% bar for at least one subsidiary directly. Every other subsidiary must have its stock held directly by one or more group members that meet the same test.

Certain corporations are excluded from the group even when the 80% ownership is there. Tax-exempt organizations under Section 501, foreign corporations, regulated investment companies and REITs taxed under Subchapter M, DISCs, and S corporations are all outside the definition of an includible corporation. Domestic insurance companies taxed under Section 801 are also excluded, though a special election can bring them in after five consecutive years as a group member.⁷ An excluded corporation files its own return and does not appear on Form 851, even if the group owns 100% of it. A common mistake involves S corporation subsidiaries: the S corporation itself is never includible, but any C corporation subsidiaries it owns could still form their own affiliated group if the ownership chain meets the 80% test.

Part I: Allocating Tax Payments Among Members

Part I allocates the group’s estimated tax payments, prior-year overpayment credits, and any tax deposited with a Form 7004 extension request among the parent and each subsidiary. For each corporation, enter the credited overpayments and the estimated payments the corporation made on its own behalf. The totals must reconcile with the corresponding lines on the consolidated Form 1120.²

Every corporation gets a Corporation Number in Part I, and that number carries through the rest of the form. The parent is always Corporation Number 1. Because the number is how each subsidiary is identified across all four parts, keep the numbering consistent.

Part II: Subsidiary Details and Stock Ownership

Part II is the longest section. For each subsidiary, report the Principal Business Activity, the corresponding six-digit PBA code from the North American Industry Classification System listed in the Form 1120 instructions, and whether the subsidiary made any nondividend distributions during the year.⁸ Pick the most specific code that describes the subsidiary’s primary income-producing activity.

Part II also documents the ownership chain at the beginning of the tax year. For each subsidiary, enter the number of shares held, the percentage of voting power those shares represent, the percentage of total stock value, and the Corporation Number of the shareholder that owns the stock.² This is where you prove the 80% test at every link. If the parent owns 100% of Subsidiary A, and Subsidiary A owns 85% of Subsidiary B, both links must appear.

Watch the distinction between voting power and outstanding shares. A corporation with multiple classes of stock might have one class carrying all voting rights and another carrying none, so the percentage of shares owned and the percentage of voting power those shares deliver can be very different numbers. Part II asks for both.⁷

Part III: Changes in Stock Holdings During the Year

Part III tracks every stock transaction that altered group membership or ownership percentages during the year. For each change, identify the corporation whose stock changed hands, the shareholder corporation, the date, the number of shares acquired or disposed of, and the resulting voting power and value percentages after the transaction.²

Part III also asks several follow-up questions that are easy to overlook. Report whether any transfer of subsidiary stock involved a share whose tax basis exceeded its fair market value at the time of transfer. Report whether any subsidiary stock became worthless under Section 165 during the year. If the beneficial owner of any stock differs from the record holder, explain the discrepancy. And if a member corporation issued new stock or retired existing shares, list the dates and amounts.

Part III should reconcile with Part II. Beginning-of-year ownership from Part II, adjusted for the changes reported here, should produce year-end ownership. A corporation that joined or left the group during the year shows up in this section as the triggering transaction.

Part IV: Additional Stock Information

Part IV consists of three yes-or-no questions that test the edges of the 80% requirement.² The first asks whether any member had more than one class of stock outstanding during the year; when multiple classes exist, the voting power and value of each class must be considered separately to determine whether the 80% threshold is met. The second asks whether any member rejoined the group within 60 months of previously leaving it, and a “yes” answer requires a full explanation. The third asks whether any arrangement existed that would let someone outside the group acquire stock or voting power in a member corporation, other than a trivial amount.

Stock options, warrants, and convertible debt all sit inside that third question. Under Treasury regulations, options and warrants are generally not treated as stock and not considered exercised for the 80% ownership test.⁹ Certain options can be treated as exercised when specific conditions are met, which could affect whether a subsidiary still qualifies as a group member. If the group has issued any options or convertible instruments to outsiders, this is where to disclose that.

When a Member Joins or Leaves Mid-Year

Group changes rarely fall on the first or last day of the tax year. The end-of-the-day rule sets the timing: a corporation that joins or leaves a consolidated group during the year is treated as changing status at the end of the day the change occurs, and its tax year ends for all federal income tax purposes at the end of that day.¹⁰

There is an exception for an S corporation whose S election terminates because it becomes a group member. That corporation becomes a member at the beginning of the day the S election terminates, not the end, and its final S corporation tax year ends the day before.

A next-day exception also applies. If a transaction on the change date is properly allocable to the portion of the day after the event that triggered the status change, the corporation and its related parties must treat that transaction as occurring at the beginning of the following day.¹⁰ A bonus paid to an executive on the same day as an acquisition that brings the corporation into the group, but tied to pre-acquisition operations, gets allocated to the pre-consolidation short year under this rule.

These timing rules shape what appears on Form 851. Dates in Part III must reflect end-of-day or next-day treatment, and the member’s income for the period before or after the change belongs on a separate short-period return rather than the consolidated return.

Records Behind the Form

The records that support Form 851 need to survive well past the return itself. The IRS requires you to keep records as long as they remain relevant to the administration of any tax provision.¹¹ Because Form 851 establishes the ownership chain that supports every item on the consolidated return, the underlying records can remain material for years.¹² Keep stock ledgers, acquisition agreements, corporate minutes documenting stock issuances or retirements, and any documents showing changes in ownership percentages.

1
Internal Revenue Service. About Form 851, Affiliations Schedule
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Internal Revenue Service. Instructions for IRS Form 851
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Internal Revenue Service. Publication 509 – Tax Calendars
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Internal Revenue Service. About Form 7004, Application for Automatic Extension of Time to File Certain Business Income Tax, Information, and Other Returns
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Office of the Law Revision Counsel. 26 USC 1501 – Privilege of Filing Consolidated Returns
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Internal Revenue Service. About Form 1122, Authorization and Consent of Subsidiary Corporation to be Included in a Consolidated Income Tax Return
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Office of the Law Revision Counsel. 26 USC 1504 – Definitions
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Internal Revenue Service. Instructions for Form 1120
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eCFR. 26 CFR 1.1504-4 – Treatment of Warrants, Options, Convertible Obligations, and Other Similar Interests
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GovInfo. 26 CFR 1.1502-76 – Taxable Year of Members of Group
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Internal Revenue Service. Topic No. 305, Recordkeeping
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Internal Revenue Service. How Long Should I Keep Records