Under the standard QSBS (Section 1202) rules, the capital gains exclusion is capped on a per-taxpayer, per-issuer basis at the greater of 10 times the taxpayer's adjusted tax basis in the stock or a flat dollar threshold. For stock issued on or before July 4, 2025, that baseline cap sits at $10M. Following the passage of the One Big Beautiful Bill Act (OBBBA), the standard exclusion cap increased to $15M for qualifying stock issued after July 4, 2025, alongside a tiered holding period starting at three years and an expanded $75M gross assets threshold. (Both the expanded exclusion cap and the $75M gross assets threshold are subject to annual inflation adjustments beginning after 2026.)
When a startup scales toward a high-valuation exit, founders sitting on low-basis common stock often realize their personal gain will far exceed that $10M or $15M ceiling. To shield the remaining gains, tax advisors and estate planners frequently turn to a popular wealth planning strategy known as QSBS trust stacking.
The mechanics of QSBS stacking rely on two foundational elements of Section 1202: the per-taxpayer exclusion cap and the statutory gift carryover rule. Because the Internal Revenue Code defines a taxpayer as any person or separate taxable entity subject to federal tax, each distinct taxpayer holding stock in the same issuing C corporation receives an independent gain exclusion cap. Furthermore, Section 1202(h) provides that when QSBS is transferred by gift, the stock retains its qualified status and holding period in the hands of the recipient, who also takes the donor's original tax basis under the general carryover basis rules for gifts.
Founders execute trust stacking by gifting blocks of their startup shares into one or more irrevocable non-grantor trusts. Unlike a grantor trust, which is disregarded as an extension of the founder for income tax purposes, a properly drafted non-grantor trust is recognized as a separate taxpayer. If a founder expects a $45M gain on pre-July 2025 stock, gifting shares early on to three separate non-grantor trusts for family members can theoretically turn a single $10M exclusion into $40M of federally tax-free gain: $10M for the founder and $10M for each trust.
Planners typically structure these transfers as either completed gifts or incomplete gifts. A completed gift uses up a portion of the founder's lifetime gift and estate tax exemption and removes the appreciating equity from the founder's taxable estate. Incomplete gift non-grantor trusts, often established in trust-friendly jurisdictions and referred to as DINGs in Delaware or NINGs in Nevada, allow the grantor to retain enough limited power over the assets to avoid a completed gift for gift tax purposes while still shifting the income tax identity to the trust. The trade-off is that the assets generally remain in the grantor's taxable estate.
These structures are also frequently explored for state income tax planning, but state rules vary widely. California, for example, does not conform to Section 1202 at all, so California residents get no state-level QSBS exclusion to multiply. California (since 2023) and New York also treat incomplete gift non-grantor trusts as grantor trusts for state income tax purposes, pulling that trust income back onto the founder's state return.
While QSBS trust stacking is legal under current statutory rules, it is far from a simple paper exercise. Executing a trust stacking strategy requires genuine economic separation and early action. A founder who places stock into a non-grantor trust gives up direct personal control over that equity. For the strategy to hold up, each trust must be grounded in authentic estate planning goals rather than functioning as a hollow shell created solely to multiply tax exclusions.
These structural hurdles have become more urgent due to heightened attention from federal tax officials. On May 20, 2026, Kenneth Kies, Treasury's Assistant Secretary for Tax Policy and acting IRS Chief Counsel, told a Washington tax seminar that Treasury is taking a close look at QSBS stacking, warning practitioners that "we don't like stacking" and signaling that guidance is being developed. A Treasury attorney-adviser made similar comments earlier that month, and the Wall Street Journal reported on June 29 that Treasury and the IRS were preparing guidance. Officials' stated concern is not traditional estate planning where a founder creates one trust per child. It is arrangements that go beyond one trust per family member, such as repetitive trusts with overlapping beneficiaries and friendly trustees that multiply exclusions without real economic division.
As of this writing, no proposed or final regulation, notice, or revenue ruling specifically addressing QSBS trust stacking has been issued, and the scope and timing of any guidance remain uncertain.
Even before new guidance is released, the IRS has tools to challenge poorly constructed trust stacks. Under Section 643(f), the IRS can treat two or more trusts as a single trust if they have substantially the same grantor and primary beneficiaries and a principal purpose of avoiding federal income tax. If a stack of trusts were aggregated under Section 643(f), they would share a single Section 1202 cap, eliminating the benefit of the additional trusts. Some commentators note that using Section 643(f) specifically to collapse QSBS trusts could face a textual challenge, but well-designed plans should not depend on that argument.
Timing matters as well. Founders who wait to transfer shares until a letter of intent is signed or an acquisition is imminent risk running afoul of the judicial assignment of income doctrine, which allows the IRS to tax the founder directly if the economic gain was effectively locked in before the gift occurred. Acquirers and M&A deal teams are also conducting heavier diligence on cap tables, scrutinizing when trust gifts were made and how independently those trusts are administered.
Given the timing requirements, loss of asset control, and increasing regulatory scrutiny surrounding multiple non-grantor trusts, many founders are looking for other ways to expand their QSBS exclusion. One practical substitute is a Section 1045 QSBS rollover, which shifts the planning focus from multiplying taxpayers to multiplying eligible corporate issuers.
While trust stacking relies on the per-taxpayer rule by splitting stock of a single company among multiple taxpayers, a QSBS rollover leverages the per-issuer rule. Under Section 1202, a single founder is entitled to a separate $10M or $15M gain exclusion cap, subject to applicable inflation adjustments, for every distinct C corporation in which they hold qualifying stock. A QSBS rollover allows a non-corporate taxpayer who sells QSBS held for more than six months to defer capital gains tax by reinvesting the sale proceeds into replacement QSBS of one or more qualifying domestic C corporations within 60 days. Gain is deferred only to the extent the proceeds are reinvested, and the replacement stock must be acquired at original issuance, not bought from another shareholder.
Historically, founders and investors viewed QSBS rollovers primarily as a rescue mechanism when a startup exited before reaching the five-year holding period required to claim the full Section 1202 exclusion. The original stock's holding period tacks onto the replacement stock, so the clock does not restart. A QSBS rollover can also be useful when a founder has already satisfied the holding period and faces an exit that exceeds their personal exclusion cap. In that scenario, the founder can claim the initial $10M or $15M exclusion on the first portion of the gain and elect a Section 1045 rollover for the rest, reinvesting the corresponding proceeds into replacement stock across multiple new companies.
For example, consider a founder who sells pre-OBBBA stock purchased in 2020 for $26M of total gain on near-zero basis. Rather than having gifted shares to trusts years earlier, the founder keeps full ownership through the exit, claims the $10M exclusion on their personal return, and reinvests roughly $16M of the sale proceeds into two different qualifying C corporations within 60 days. Because the replacement shares are newly issued stock of separate issuers, each new investment carries its own per-issuer exclusion cap. The $16M of deferred gain is not excluded at the time of the rollover. It becomes eligible for exclusion later, when the replacement stock is sold, provided the replacement companies remain qualified and the combined holding period requirements are met.
One caveat on caps: if the original stock was issued before July 5, 2025, rolling the proceeds into a company that issues stock after that date is generally not expected to upgrade the rolled gain to the $15M cap or the tiered holding period. Commentators read the OBBBA's acquisition-date rules together with the holding period tacking rule of Section 1223(13) as preserving the pre-OBBBA regime for rolled gain, though this point has not been addressed in formal guidance. Even so, spreading the deferred gain across two or three new issuers can still multiply the founder's baseline $10M exclusion across each new corporation.
Choosing between trust stacking and QSBS rollovers comes down to a founder's timeline, appetite for complexity, and long-term goals for their capital. Well-designed trust stacking remains an effective strategy when a founder has genuine estate and family wealth transfer objectives and makes the gifts years before an exit, while valuations are low. Done properly, with distinct beneficiaries and independent trustees, a conservative trust plan aligns with how the statute was written.
For founders who do not want to permanently part with control of their net worth, who have small families that would make multiple trusts look artificial, or who are already too close to a liquidity event to avoid assignment of income challenges, a QSBS rollover can offer a cleaner path. The founder retains ownership and control of the reinvested capital in their own name. Substantiating a rollover also leans more on corporate and financial records, such as issuance dates, gross asset figures, and active business activity, than on proving non-tax motives for creating multiple family trusts.
Rollovers carry their own risks, however. The founder must deploy a large sum into early-stage companies within 60 days, which concentrates risk and ties up capital in illiquid positions. The rolled gain is only deferred until the replacement stock itself qualifies. The replacement companies must be legitimate operating businesses that satisfy the active business requirement and the gross asset test at issuance. Passive or founder-controlled shells set up mainly to receive rollover proceeds invite challenge under the anti-abuse authority of Section 1202(k). When those conditions are met, a rollover gives founders a statutory path to multiply their exclusions while putting capital to work in their next venture or startup portfolio.
This article is for general information and is not tax or legal advice. Founders should confirm the current status of Treasury guidance and their specific facts with a qualified tax advisor.
