8.4 Controlled Groups & Closely Held Corporations

Different ownership tests serve different purposes

A business can divide operations among several corporations without creating a separate full set of tax benefits for every corporation. Controlled-group provisions aggregate corporations for specified purposes. An affiliated group eligible to elect consolidated income-tax reporting is related but different. A closely held corporation is another classification, relevant particularly to at-risk and passive-activity losses. Identify the statutory purpose before applying an ownership percentage.

Do not assume that a group must file a consolidated return whenever there is common ownership. Consolidated reporting generally requires an eligible affiliated group and a valid election. Conversely, separate returns do not defeat all aggregation. Commonly controlled businesses can be treated as one taxpayer or employer for particular limits even though they keep separate books and separate EINs.

Parent-subsidiary and brother-sister groups

Under §1563, a parent-subsidiary controlled group generally consists of chains of corporations connected through stock ownership meeting the applicable 80% voting-power or value test. Trace ownership through the chain and apply the correct excluded-stock and attribution rules. This test is not the same as §351's rule requiring 80% voting control and 80% of each nonvoting class for an incorporation transaction.

For a typical brother-sister analysis, the same five or fewer qualifying persons must satisfy both an 80% controlling-interest test and a more-than-50% effective or identical-ownership test, using voting power or value as applicable. For the identical-ownership test, each person's interest counts only to the extent it is identical in each corporation. Family and entity attribution can change the ownership schedule, so the directly registered shareholders are only the starting point.

Dana and Eli together own all of both corporations and their identical ownership totals 70%, exceeding 50%. Assuming all other requirements are met, the brother-sister test is satisfied. If instead Dana owned 95% of A and 5% of B, while Eli owned the reverse, identical ownership would total only 10%; common names on both shareholder lists would not by itself establish the second test.

Consequences of control

Component members of a controlled group share specified tax benefits rather than each taking a full independent amount. Schedule O (Form 1120) addresses allocation of certain benefits. The flat 21% corporate tax rate means that old graduated-bracket planning examples do not describe 2025 law, but aggregation still matters for other limits. The §179 ceiling, portions of the general-business-credit limitation, and other provisions have their own group rules.

For the §448(c) gross-receipts test, apply the aggregation provisions referenced by that test. For 2025, the basic threshold is $31 million of average annual gross receipts for the preceding three tax years. An owner cannot necessarily place $20 million of receipts in each of two related corporations and claim each is independently below the threshold. Determine the controlled or affiliated-service relationships and aggregate as the governing provision requires.

Retirement-plan coverage and ACA employer size also have common-control rules. The precise percentage and attribution provisions depend on the statute. Recognizing a group for one purpose is a signal to test other provisions, not permission to reuse one ownership result without checking its definition.

Closely held C corporations and losses

For the passive-activity rules, a closely held corporation generally is a C corporation in which more than 50% of the outstanding stock's value is owned directly or indirectly by five or fewer individuals during the last half of the tax year, excluding a personal service corporation under the applicable definition. A closely held corporation can generally use passive losses against net active business income, but not against portfolio income. Personal service corporations generally face the stricter passive-income limitation.

The at-risk rules can separately apply to closely held C corporations. A deductible economic loss must pass the applicable investment-risk limitations; nonrecourse debt is not automatically at risk. Form 8810 addresses corporate passive activities, while Form 6198 addresses at-risk limitations where applicable. Distinguish these from the individual owner's Form 8582.

Scenario: A closely held manufacturing C corporation has $80,000 of net active income, $30,000 of portfolio interest, and a $100,000 passive rental loss, with sufficient at-risk investment. Under the general closely held corporation rule, $80,000 can offset net active income, while $20,000 remains suspended; the portfolio interest is not a source of passive-loss capacity. An S corporation instead passes activity information to shareholders, who apply their own limitations.

Official references

2025 Schedule O (Form 1120) instructions, Publication 925, and §1563 ownership definitions, checked October 17, 2026.