What is QSBS stacking? Definition, how it works and examples
Why the per-taxpayer cap invites gifts to family members and non-grantor trusts — how stacking is structured, what the law allows, and where the anti-abuse rules stop it.
The short answer
What is QSBS stacking? QSBS stacking means spreading qualified small business stock across several taxpayers — usually family members or non-grantor trusts, by gift — so that each one claims its own Section 1202 cap. The cap is up to $15 million per company per taxpayer, so more taxpayers can mean more excluded gain. It matters only when the expected gain on one company is larger than one cap, which in practice means founders and the earliest investors in a company that is heading for a large exit. The structures work because the law allows gifts to carry QSBS status.
How does QSBS stacking work?
The cap in Section 1202(b) is written per taxpayer and per issuer: each taxpayer may exclude gain on one company’s stock up to the greater of the dollar limit or ten times their basis in the shares sold. The dollar limit is cumulative — reduced by what that taxpayer excluded on the same company in earlier years. A second taxpayer has a cap of its own. The bridge is Section 1202(h).
What is a QSBS trust?
A QSBS trust is a trust that receives qualified stock by gift and is its own taxpayer, so it has its own Section 1202 cap. That last condition is the one that matters. A grantor trust is ignored for income tax: under Section 671 its income is the grantor’s, so its gain sits under the grantor’s cap and adds nothing. Only a non-grantor trust — one where the grantor has given up the powers that make it a grantor trust — counts separately. A non-grantor trust pays its own income tax, at compressed trust rates. The gain above its cap is taxed in the trust unless distributed.
What is QSBS trust stacking, and where does it stop?
QSBS trust stacking is the use of several non-grantor trusts, each holding part of the stock, each claiming a cap. The limit is Section 643(f). It treats two or more trusts as one if they have substantially the same grantor and substantially the same primary beneficiary, and a principal purpose of avoiding income tax. For this rule a husband and wife are one person. In practice that means stacking trusts are judged one beneficiary at a time. Several trusts for the same child, set up by the same parents, risk being collapsed into one trust with one cap.
Worked example: one founder, one cap or three
A founder buys common stock at formation in September 2025 for $2,000, from a Delaware C corporation that passes every Section 1202 test. Early on, while the shares are worth little, the founder gives a quarter of them to each of two non-grantor trusts, one for each child. Six years later the company is sold and the whole block fetches $60 million. The difference is the size of two extra caps, taxed at 23.8%. It exists only if every assumption in the caption holds.
The rules behind QSBS stacking trusts, as of October 2026
Common mistakes with QSBS stacking
Using a grantor trust Many estate-planning trusts are grantor trusts by design. They do not create a second cap. Several trusts for one beneficiary Same grantor, same beneficiary and a tax purpose is the fact pattern Section 643(f) targets. Waiting for the term sheet A gift made as a sale closes is worth more for gift tax and weaker against an assignment-of-income argument. Stacking stock that does not qualify A gift carries status; it does not create it. If the shares fail Section 1202 in the donor’s hands, every trust fails too.
The terms this page uses
QSBS stacking Spreading qualified stock across several taxpayers by gift so each can claim a Section 1202 cap on the same company. Per-issuer cap The most gain one taxpayer may exclude on one company’s stock: the greater of $15M ($10M for older stock) or ten times basis. Non-grantor trust A trust that is its own income taxpayer, because the grantor has not kept the powers that make it a grantor trust. Grantor trust A trust whose income is taxed to the person who funded it. For QSBS it shares that person’s cap.
Questions about QSBS stacking
Is QSBS stacking legal? The building blocks are in the statute: the cap is per taxpayer, and gifts keep QSBS status under Section 1202(h). Whether a given structure holds depends on facts — the type of trust, the beneficiaries, the timing and the drafting. Section 643(f) and the anti-avoidance authority in Section 1202(k) are the limits. Do QSBS stacking trusts have to be non-grantor trusts? To add a cap, yes. A grantor trust’s income is the grantor’s for income tax, so its gain counts against the grantor’s cap. Can I gift QSBS shares to my spouse to double the cap?
Is QSBS stacking legal?
The building blocks are in the statute: the cap is per taxpayer, and gifts keep QSBS status under Section 1202(h). Whether a given structure holds depends on facts — the type of trust, the beneficiaries, the timing and the drafting. Section 643(f) and the anti-avoidance authority in Section 1202(k) are the limits.
Do QSBS stacking trusts have to be non-grantor trusts?
To add a cap, yes. A grantor trust’s income is the grantor’s for income tax, so its gain counts against the grantor’s cap.
Can I gift QSBS shares to my spouse to double the cap?
Not on a joint return: the excluded gain is allocated equally between spouses and they share one cap. On separate returns each spouse has half of it.
Does the holding period restart after a gift?
No. The recipient is treated as having held the shares for the donor’s holding period, and as having acquired them in the same way.
Does stacking apply to shares held through an SPV?
Only if the vehicle itself holds QSBS — shares acquired at original issue — and passes the gain through under the partnership rules. A vehicle that bought on the secondary market has no QSBS to stack.
Where every rule on this page comes from
Every rule and figure was checked against the US Code and the IRS on 2 October 2026 and reflects federal law as amended on 4 July 2025. The worked example is illustrative arithmetic, not a client case and not market data. Gift, estate and state tax are not covered beyond the figures cited.