Under 26 USC 1504, an affiliated group is a chain of includible corporations linked through a common parent corporation that directly owns stock representing at least 80% of the voting power and at least 80% of the total value of at least one other includible corporation, with each additional member connected to the chain by the same 80% direct-ownership test. If the group meets that definition, it may elect to file a single consolidated federal income tax return that combines the income and losses of every member.
The 80% Vote-and-Value Test
The definition has two prongs, and both must be satisfied independently. The parent (or another member) must own stock carrying at least 80% of the total voting power of the subsidiary, and that same stock must represent at least 80% of the total value of the subsidiary’s stock.1Office of the Law Revision Counsel. 26 USC 1504 – Definitions Holding 95% of the value while controlling only 70% of the vote fails the test. So does the reverse.
A group can extend well beyond a single parent-subsidiary pair. If the parent owns 80% of Corporation A, and Corporation A owns 80% of Corporation B, then B is part of the affiliated group. The rule is that each corporation in the chain other than the parent must have its qualifying stock owned directly by another member of the group.1Office of the Law Revision Counsel. 26 USC 1504 – Definitions Ownership held indirectly through partnerships, trusts, or individuals does not count. The chain runs corporation to corporation.
Stock That Does Not Count
Certain preferred stock is disregarded when running the 80% calculation, but only if it meets all four of the following conditions: it carries no voting rights, its dividends are limited and preferred with no meaningful participation in corporate growth, its redemption and liquidation rights do not exceed the issue price (other than a reasonable premium), and it is not convertible into another class of stock.1Office of the Law Revision Counsel. 26 USC 1504 – Definitions Miss any single condition and the shares count as stock for the ownership test.
Options and Warrants
Treasury has broad authority to write regulations treating warrants, convertible obligations, and options to acquire or sell stock as if they had already been exercised.2Office of the Law Revision Counsel. 26 U.S. Code 1504 – Definitions A parent sitting at 75% direct ownership that also holds options for another 10% could be treated as meeting the threshold. A parent at 85% could fall out of affiliation if outstanding options held by outsiders would dilute its stake below 80% when deemed exercised.
Corporations That Cannot Be Members
Meeting the 80% test is necessary but not sufficient. The statute pulls six categories of corporations out of the affiliated group entirely, even when the ownership math works.1Office of the Law Revision Counsel. 26 USC 1504 – Definitions
- Corporations exempt from tax under section 501. The exclusion sweeps in every type of 501 entity, not only traditional charities.
- Insurance companies taxed under section 801, subject to the special election described below.
- Foreign corporations, regardless of how much stock a U.S. parent owns.
- Regulated investment companies and real estate investment trusts, which receive pass-through treatment under Subchapter M.
- Domestic international sales corporations (DISCs), which have their own export-related regime.
- S corporations. Because an S corporation passes income through to its shareholders, it cannot itself join a consolidated return. A C corporation subsidiary of an S corporation can still form its own affiliated group with other qualifying C corporations, but the S corporation stays out.
The Life Insurance Company Exception
Insurance companies get a partial path back in. Two or more domestic life insurance companies connected through 80% ownership can form their own affiliated group and file consolidated among themselves. Where a broader group includes both life insurers and non-insurance corporations, the common parent can elect to bring the insurers into the consolidated return, but only if the insurance company has been a member of the affiliated group for at least five consecutive tax years.2Office of the Law Revision Counsel. 26 U.S. Code 1504 – Definitions
How the Group Elects Consolidated Filing
The authority for consolidated returns comes from 26 USC 1502, which directs Treasury to write regulations governing how affiliated groups compute and report their combined tax.3Office of the Law Revision Counsel. 26 U.S. Code 1502 – Regulations The group makes the election by filing Form 1120 as a consolidated return, attaching a separate Form 1122 from each subsidiary consenting to be included.4Internal Revenue Service. About Form 1122, Authorization and Consent of Subsidiary Corporation to be Included in a Consolidated Income Tax Return
Once made, the election is binding. In each later year the group must continue filing consolidated unless the IRS grants permission to stop. That permission requires a formal application to the Commissioner showing good cause, filed at least 90 days before the consolidated return’s due date. The IRS will generally approve a request when recent changes to the tax code create a substantial disadvantage for consolidated filers compared to separate filing.5GovInfo. 26 CFR 1.1502-75 – Filing of Consolidated Returns Regretting the election is not enough. Calendar-year corporations that need more time can file Form 7004 for an automatic six-month extension.6Internal Revenue Service. Publication 509 (2026), Tax Calendars
Every Member Is Liable for the Whole Tax
Joining a consolidated group changes each member’s exposure to the IRS. The regulations impose joint and several liability on the common parent and every subsidiary that was a member during any part of the consolidated return year.7eCFR. 26 CFR 1.1502-6 – Liability for Tax If the group owes $10 million and the parent cannot pay, the IRS can collect the full amount from any one subsidiary.
Private allocation agreements do not bind the IRS.7eCFR. 26 CFR 1.1502-6 – Liability for Tax A subsidiary that is sold out of the group still remains liable for the group’s taxes covering every year it was a member. That risk carries into due diligence on any sale or acquisition of a former group member.
A Corporation That Leaves Cannot Rejoin for Five Years
Once a corporation stops being a member, it cannot be included again in the group (or any group with the same common parent) for 61 months, measured from the first month of the tax year in which it left.2Office of the Law Revision Counsel. 26 U.S. Code 1504 – Definitions The waiting period stops groups from cycling subsidiaries in and out to harvest favorable loss years. The Treasury Secretary can waive the restriction, but waivers come with conditions and are not routine.
Losses a New Member Brings In
A corporation joining an affiliated group often arrives with net operating losses from prior separate-return years. The group cannot freely use those losses against other members’ income. Under the Separate Return Limitation Year (SRLY) rules, pre-affiliation losses can offset only the income that the loss member itself generates while inside the consolidated group.8eCFR. 26 CFR 1.1502-15 – SRLY Limitation on Built-in Losses
The same treatment reaches built-in losses, meaning unrealized losses sitting in the new member’s assets when it joins. If the member sells such an asset at a loss within the recognition period, the loss is treated as a hypothetical net operating loss carryover and subjected to the SRLY cap, so the deduction in any year is limited to the member’s own contribution to consolidated taxable income.8eCFR. 26 CFR 1.1502-15 – SRLY Limitation on Built-in Losses
When multiple corporations join a new group at the same time from a common former group, they can be treated as a SRLY subgroup, pooling losses and income for the limitation. Subgroup treatment is more favorable than tracking each member separately. If a member later separates from its subgroup, its share of remaining losses is allocated by formula.9Internal Revenue Service. Consolidated Returns – Limitations on the Use of Certain Losses and Deductions (TD 8823)
What to Confirm Before Electing
Before a group files its first consolidated return, three things are worth pinning down. First, that the 80% vote-and-value test is met by each includible member through direct corporate ownership, with any preferred stock, options, or convertible instruments analyzed against the statutory carve-outs. Second, that no member falls into one of the six excluded categories, or, for life insurers, that the five-year membership condition is satisfied before including them. Third, that every member understands the election is binding, that liability for the group’s tax is joint and several, and that a departing member cannot rejoin for 61 months. Getting these right at the outset avoids the retroactive disallowance risk, because if the IRS later concludes the group never met the affiliation requirements, each member must unwind and file separately for the affected years.