QSBS Stacking: How to Multiply the $15M Exclusion

The §1202 exclusion is capped at the greater of $15M or 10× basis — but that cap is per taxpayer, per issuer. Each separate taxpayer who holds your QSBS gets their own cap. "Stacking" (sometimes called "packing" when you increase a single holder's basis) is the practice of spreading shares across multiple taxpayers — non-grantor trusts and family members — so each one claims a full exclusion on the same company.

The core mechanic: if you alone hold a $45M QSBS gain, only $15M is excluded and $30M is taxable. But if that stock is spread across you, a non-grantor trust for your kids, and another for your parents — three taxpayers — each can potentially exclude $15M, sheltering the entire $45M. The savings on that extra $30M is roughly $7M in federal tax. This only works if the structure is in place before the sale.

Why it works: "per taxpayer, per issuer"

Section 1202 caps the exclusion at the holder level. Two things follow. First, the same shareholder can claim the cap separately for each different company they hold QSBS in (per issuer). Second — and this is the lever — a different taxpayer who holds QSBS in the same company gets their own independent cap. The strategy is to create or use additional eligible taxpayers and place qualifying shares with them.¹

The main stacking vehicles

Non-grantor trusts

A properly structured non-grantor trust is a separate taxpayer for income-tax purposes — so it has its own $15M QSBS cap. Founders gift QSBS shares into one or more irrevocable non-grantor trusts (often for children or other beneficiaries) well ahead of a liquidity event. Each trust can then exclude its own $15M of gain. This is the workhorse of serious QSBS stacking.

The distinction matters: a grantor trust is treated as you for income tax, so it shares your cap and adds nothing. The trust must be drafted as non-grantor (and stay that way) to get a separate exclusion. That's a job for an estate attorney, not a template.

Spousal gifting

Gifts between spouses are tax-free and the donee spouse takes a carryover basis and a tacked holding period. A spouse who holds QSBS is a separate taxpayer with their own cap — so married founders can often double the exclusion to $30M. Note the IRS aggregates a married couple filing jointly to a single $15M cap on stock they hold together; the planning is about the spouse holding shares in their own right or through their own trust.

Gifting to family members

Outright gifts of QSBS to adult children, parents, or siblings transfer the stock with carryover basis and a tacked holding period — meaning the recipient inherits your clock and doesn't have to start over. Each is a separate taxpayer with a separate cap. This trades some control for exclusion capacity, and uses lifetime gift-tax exemption, so it's part of a broader estate plan.

Packing: increasing the 10× lever

Stacking adds taxpayers; packing increases a single holder's cap by increasing basis, because the cap is the greater of $15M or 10× basis. Contributing additional capital, or structuring an exercise to raise basis, can lift the 10×-basis figure above $15M. For investors with substantial basis this is often the bigger number — and it stacks (so to speak) with the multi-taxpayer approach.

The rules that make or break a stack

Do it before the sale — ideally well before. Gifting shares the week before a signed acquisition invites step-transaction and assignment-of-income challenges. The earlier and cleaner the transfer, the stronger the position.
The gift must be complete. You have to actually give up control; strings attached can collapse the structure back to you.
Carryover holding period helps you. Because the recipient tacks your holding period, gifting doesn't restart the 5-year clock — a crucial feature when a liquidity event is near.
Non-grantor status must hold. A trust that's inadvertently a grantor trust shares your cap. This needs careful drafting and ongoing administration.
State conformity still applies. Trust situs and the beneficiaries' states matter; a trust in a non-conforming state can lose the state-level benefit.
It's an estate-planning act, not just a tax move. You're permanently transferring wealth. Stacking should fit your broader estate and gifting plan, not fight it.

Timing is everything. The single most common way founders lose stacking is waiting until the deal is in motion. Once a sale is reasonably certain, the IRS can treat a last-minute gift as you selling and then gifting the cash — no extra exclusion. Set up trusts and complete gifts while the exit is still speculative.

Why this is specialist territory

Stacking sits at the intersection of income tax, gift and estate tax, trust law, and state conformity — and the structure has to be built years before it pays off. A fee-only advisor coordinates the moving parts with your estate attorney and CPA: how many trusts, which beneficiaries, how much to gift, how to preserve non-grantor status, and how it all fits your estate plan. Done right on a large position, it's one of the highest-return planning moves available.

Build your stack before the exit — not after

Stacking only works if the trusts and gifts are in place before a sale is certain. Get matched with a fee-only advisor who coordinates QSBS stacking with your estate attorney and CPA. No obligation.

Sources

IRC § 1202(b) — per-taxpayer, per-issuer limitation on excludable gain.
The Tax Adviser — QSBS gets a makeover: Sec. 1202's new look (Nov 2025) (post-OBBBA $15M cap and tiers).

Stacking involves irrevocable transfers with gift-tax and estate consequences and must be structured before a sale is certain. This is educational only — not legal or tax advice. Work with an estate attorney and tax counsel.