Rules of Attribution: Family, Entities, and Section 318

Constructive ownership of stock is a federal tax concept that treats you as owning shares held by people and entities close to you, even when your name is not on those shares. Section 318 of the Internal Revenue Code sets the rules: stock held by your spouse, children, grandchildren, and parents counts as yours, and so does stock held by partnerships, estates, trusts, and corporations you are connected to, within specific limits. The rules exist to stop taxpayers from splitting formal ownership among relatives or controlled entities to duck tax thresholds, and they can turn what looked like a capital-gains sale into a fully taxable dividend.¹

Which Family Members Count

Section 318 draws a tight family circle. You are treated as owning stock held by your spouse, children (including legally adopted children), grandchildren, and parents. The attribution runs both ways within that group: a parent is treated as owning a child’s stock, and a child is treated as owning a parent’s stock.¹

The circle is smaller than most people expect. Siblings, grandparents, aunts, uncles, and in-laws are all outside it. If your brother holds 40 percent of a company and you hold 10 percent, Section 318 does not combine those stakes. A spouse who is legally separated under a divorce decree or separate maintenance agreement is also outside the circle; until the decree is final, the attribution still applies.¹

A quick example shows why this matters. A father owns 50 shares of a corporation and his daughter owns another 50. The father constructively owns all 100. If the corporation redeems the father’s 50 shares, he still constructively owns his daughter’s 50 afterward, so the IRS can treat the payout as a dividend rather than a sale. Cash in hand, and yet the transaction reads as a distribution.

Stock Held by Partnerships, Estates, Trusts, and Corporations

Stock flows down from entities to the people behind them, but the math depends on the entity.

Partnerships and Estates

When a partnership or estate owns stock, each partner or beneficiary is treated as owning a proportionate slice. A one-third partner in a partnership that holds 60 shares is deemed to own 20 of them. There is no minimum ownership threshold; a 1-percent partner picks up a proportionate share.¹

Trusts

For a standard trust, stock is attributed to each beneficiary based on their actuarial interest, not a flat percentage of trust assets. That calculation accounts for the likelihood and timing of distributions and can get complicated fast. For a grantor trust, all stock is attributed to the person treated as the owner under the grantor trust rules. Employee benefit trusts that qualify under Section 401(a) and are tax-exempt under Section 501(a) are excluded entirely.¹

Corporations

Corporate attribution has a gatekeeping threshold. You are treated as owning a corporation’s stock holdings only if you own 50 percent or more of that corporation’s stock by value. Once you clear that bar, the corporation’s holdings are attributed to you in proportion to your ownership. A 10-percent shareholder never picks up the corporation’s portfolio, no matter how large.¹

Stock You Own That Gets Attributed to Your Entities

The upward flow works asymmetrically. Any stock you own personally is attributed in full to a partnership or estate where you are a partner or beneficiary. If you hold 200 shares of an outside company and you are a 5-percent partner, the partnership is treated as owning all 200, not just 5 percent of them. The same full-attribution approach applies to trusts and estates.¹

For corporations, the same 50-percent gate applies going up. If you own at least half the value of a corporation’s stock, all of your personal stockholdings elsewhere are attributed to that corporation. Below the threshold, the corporation picks up nothing from you.¹

An S corporation is treated as a partnership for Section 318 purposes, and its shareholders are treated as partners. The proportionate downward rule and the full upward rule both apply to S corporation shareholders the same way they apply to partners. The one carve-out: this treatment does not apply when determining whether stock in the S corporation itself is constructively owned.¹

Options Count as Stock

If you hold an option to buy stock, you are treated as already owning that stock. It does not matter that you have not exercised the option or paid the strike price. An option to acquire an option, and any chain of options leading to stock, counts the same way.¹

The option rule has statutory priority over family attribution. When stock could be attributed to you either because a family member holds it or because you hold an option on it, the law treats you as owning it by reason of the option. That distinction has real consequences for the reattribution limits below, because stock attributed through options can be reattributed further, while stock attributed through family rules generally cannot.¹

Limits on Chaining the Rules

Without guardrails, attribution could chain indefinitely: your spouse’s stock becomes yours, then yours becomes your parent’s, and suddenly an entire extended family constructively owns each other’s shares. As a general matter, constructively owned stock is treated as actually owned for the purpose of applying the attribution rules a second time. Two prohibitions cut off the chain:¹

Stock attributed to you through the family rule cannot be attributed again through the family rule to a second person. Stock a husband constructively owns because of his wife’s holdings does not jump from the husband to his parents.
Stock attributed upward to an entity from one owner cannot then be attributed downward to a different owner of that entity. Shares that reach a partnership through Partner A do not flow down to Partner B.

The asymmetry is worth noticing. Stock attributed downward from an entity to an owner can be reattributed through the family rule, because that specific combination isn’t prohibited. And stock attributed through the option rule is treated as actually owned for all reattribution purposes, which is exactly why the statute forces the option rule to take priority when both option and family attribution could apply.

Why Attribution Usually Matters: Stock Redemptions

The place most people first hit these rules is a stock buyback. When a corporation redeems your shares, the tax treatment depends on whether the redemption meaningfully reduces your ownership. If it does, you get exchange treatment and pay tax only on the gain over your basis. If it doesn’t, the entire payment is taxed as a dividend. Section 302 explicitly incorporates Section 318’s attribution rules when measuring your ownership before and after the redemption.²

A redemption qualifies for exchange treatment if it meets one of several tests, including being substantially disproportionate (your voting-stock percentage must drop below 80 percent of what it was before, and you must own less than 50 percent afterward) or completely terminating your interest. Constructively owned shares count in every one of those measurements. You can sell every share registered in your name and still be treated as a majority owner because of your spouse’s or child’s holdings.²

Waiving Family Attribution in a Complete Redemption

There is an escape hatch. If a redemption completely terminates your interest in the corporation, you can file an agreement with the IRS to waive family attribution. Three conditions apply:²

Immediately after the redemption, you hold no interest in the corporation as an officer, director, employee, or shareholder. Remaining as a creditor is allowed.
You do not reacquire any interest in the corporation (other than stock received through inheritance) within the 10 years following the redemption.
You file a written agreement with your tax return for the year of the redemption, promising to notify the IRS of any reacquisition and to retain the necessary records.

The waiver is not available if you acquired any of the redeemed stock from a related person within the 10 years before the redemption, or if a related person acquired stock from you during that same window, unless the transaction did not have tax avoidance as a principal purpose.²

Where Section 318 Applies

Section 318 does not run through the whole tax code. It applies only where another code section specifically invokes it. The main cross-references include:³

Section 302 stock redemptions (exchange treatment versus dividend).
Section 304 redemptions between related corporations.
Section 306 dispositions of preferred stock received as a dividend.
Section 338 qualified stock purchases.
Section 382 net operating loss limitations after ownership changes.
Section 856 REIT rental income tests.
Section 958 controlled foreign corporation shareholder determinations.
Section 6038 information reporting for certain foreign corporations.

If a question does not fall under one of these provisions or another section that expressly incorporates Section 318, the attribution rules do not automatically apply.

Other Attribution Systems That Use Different Rules

Section 318 is the most commonly referenced attribution framework, but it is not the only one, and its family circle is narrower than most alternatives. Applying the wrong set of rules is a frequent planning error.

Section 267, which governs disallowed losses on related-party transactions, has a broader family definition that includes siblings (full and half-blood) alongside spouses, ancestors, and lineal descendants. It also attributes stock between business partners, something Section 318 does not do.⁴

Section 544, the personal holding company rules, likewise includes siblings and applies partner-to-partner attribution, though only where doing so would make the corporation a personal holding company or increase its personal holding company income.⁵

Section 1563, used to identify brother-sister and parent-subsidiary controlled groups, sets a 5-percent minimum for partnership and trust attribution based on capital, profits, or actuarial interest, which is more restrictive than Section 318’s no-floor rule for partnerships and estates.⁶

Each section defines its own family relationships, thresholds, and reattribution limits. Confirming which framework applies is the first step in any ownership analysis.

A Note on Schedule G Reporting

Corporations that file Form 1120 may need to complete Schedule G to identify persons with significant voting power. The schedule is triggered when any person, entity, or estate owns 20 percent or more of total voting power directly, or 50 percent or more directly or indirectly. For Schedule G purposes, the constructive ownership rules of Section 267(c) apply rather than Section 318, so family attribution here includes siblings and partner-to-partner attribution applies.⁷ A corporation that applies Section 318’s narrower family definition on Schedule G can miss a sibling who should have been listed, and the disclosure gap is the kind of thing that draws audit attention.

1
Office of the Law Revision Counsel. 26 USC 318 – Constructive Ownership of Stock
2
Office of the Law Revision Counsel. 26 USC 302 – Distributions in Redemption of Stock
3
Office of the Law Revision Counsel. 26 U.S. Code 318 – Constructive Ownership of Stock
4
Office of the Law Revision Counsel. 26 USC 267 – Losses, Expenses, and Interest with Respect to Transactions Between Related Taxpayers
5
Office of the Law Revision Counsel. 26 U.S. Code 544 – Rules for Determining Stock Ownership
6
Office of the Law Revision Counsel. 26 U.S. Code 1563 – Definitions and Special Rules
7
Internal Revenue Service. Schedule G (Form 1120) Information on Certain Persons Owning the Corporation’s Voting Stock