If your company was acquired and you received the acquirer's stock for your shares, here is the answer up front: in a tax-free reorganization, your QSBS status generally survives the exchange — but your exclusion may now be capped at the gain that existed on the day of the deal. Everything the acquirer's stock has gained since then is ordinary capital gain, fully taxable when you sell. The statute that does all of this is Section 1202(h)(4), and it is one of the least-discussed provisions in the QSBS rules despite governing what happens in nearly every startup acquisition.
This post is part of our Complete Guide to QSBS and Section 1202.
The general rule: your QSBS survives the exchange
Section 1202 ordinarily requires original issuance — you must have acquired your stock directly from the corporation for money, property (other than stock), or services. Stock you receive in exchange for other stock normally fails that test. Without a special rule, every stock-for-stock acquisition would destroy QSBS status.
Section 1202(h)(4)(A) is that special rule. In a transaction described in Section 351 or a reorganization described in Section 368, stock received in exchange for QSBS is treated as QSBS "acquired on the date on which the exchanged stock was acquired." Two things follow:
- The acquirer's stock is treated as QSBS in your hands, even though the acquirer is almost never a qualified small business.
- Your holding period carries over. If you acquired your original shares in 2021 and the acquisition closed in 2024, your clock has been running since 2021.
For Section 351 exchanges (as opposed to Section 368 reorganizations), there is an additional condition: under Section 1202(h)(4)(D), the corporation issuing the new stock must, immediately after the transaction, control the corporation whose stock was exchanged, within the meaning of Section 368(c). Most startup acquisitions are structured as Section 368 reorganizations, where no separate control test applies.
The trap: the exchange-date gain cap
Here is the part that surprises people at sale time. Section 1202(h)(4)(B) limits the exclusion on the replacement stock to "the gain which would have been recognized at the time of the transfer" — that is, the gain built into your shares on the date of the exchange.
Appreciation in the acquirer's stock after the deal closes is not eligible for the exclusion. The statute freezes your excludable gain at the deal date.
There is one exception: the cap does not apply if the corporation issuing the replacement stock is itself a qualified small business at the time of the exchange. If a small C corporation acquires your company, all of the replacement stock — including future appreciation — can qualify. In practice, acquirers of venture-backed companies almost never satisfy the gross-assets test, so the cap almost always applies.
The cap is also sticky. Under Section 1202(h)(4)(C), once the limitation attaches, it is measured as of the first exchange to which it applied. A second reorganization doesn't reset it.
A worked example
Say you exercised options in 2021 with a basis of $10,000. (Under Section 1202, the holding period starts at exercise, not grant — see the clock rules below.) Your company was acquired in a Section 368 stock-for-stock reorganization in 2024, when your shares were worth $2,000,000. In 2026, you sell the acquirer stock — in a tender offer, say — for $3,500,000.
- Holding period: 2021 to 2026, more than five years including the tacked period. You clear the holding-period requirement.
- Excludable gain: capped at the exchange-date built-in gain — $1,990,000 ($2,000,000 value less $10,000 basis).
- Taxable gain: the $1,500,000 of post-exchange appreciation, plus any exchange-date gain above your per-issuer cap.
Because the original shares were issued on or before July 4, 2025, the pre-OBBBA rules apply: a $10 million cap (or 10x basis, if greater), a $50 million gross-asset ceiling for the original issuer, and a five-year cliff to the 100% exclusion. Stock issued after July 4, 2025 gets the expanded regime — the greater of $15 million or 10x basis, a $75 million gross-asset ceiling, and a tiered 50/75/100% exclusion at three, four, and five years. Nearly all acquisition-converted stock in the market today sits on the old side of that line. See Don't Accidentally Disqualify Your QSBS by "Resetting" It for why you cannot exchange your way into the new regime.
The documentation problem nobody solves at closing
The exchange-date cap makes one number decisive years after everyone stopped thinking about the deal: the fair market value of your shares on the exchange date.
At sale, you (and eventually an examiner) need to establish three things: that the original shares were QSBS, that the exchange qualified under Section 351 or 368, and what the built-in gain was on the exchange date. The first two are documentation questions. The third is a valuation question — and if you didn't capture the deal-date value when the deal happened, you are reconstructing it from old board materials, 409A reports, and merger documents years later.
If you hold acquirer stock received for QSBS, the time to paper this is now, not at sale. A written attestation memorializing original QSBS status, the reorganization, and the exchange-date value is exactly the file an examiner asks for. See What a QSBS Attestation Letter Must Say and our QSBS attestation service.
Cash deals are different
If you were cashed out, there is no Section 1202(h)(4) issue — the sale was a taxable disposition of your QSBS itself.
- Holding period met (five years for pre-OBBBA stock; the tiered three/four/five-year schedule for stock issued after July 4, 2025): the exclusion applies, up to your cap.
- Holding period not met: Section 1045 lets you roll the proceeds into new QSBS within 60 days and keep the clock running. See Section 1045 Rollover: How to Defer QSBS Gains.
Mixed consideration — part stock, part cash — is more complicated: in a reorganization, gain is generally recognized to the extent of the cash (boot), and the Section 1202 analysis has to be run on each piece. Get advice before the deal closes if you can, because consideration elections sometimes exist and they are irrevocable.
Don't confuse this with same-company conversions
Section 1202(f) covers a different situation: stock acquired on conversion of other stock of the same corporation — preferred converting to common, for example. Converted shares are treated as QSBS with a tacked holding period, and no exchange-date cap applies, because no second corporation is involved. The cap in Section 1202(h)(4)(B) is a cross-corporation rule.
The holding-period clocks, briefly
Because most acquisition-converted stock started as employee equity, the clock rules matter:
- Option exercise: the Section 1202 clock starts at exercise, not grant.
- Restricted stock without an 83(b) election: the clock starts tranche by tranche at vesting.
- Restricted stock (or early exercise) with an 83(b) election: the clock starts at the transfer date — the early-exercise date for early-exercised options.
- RSUs: the clock starts at share delivery.
The tacked period from the exchange is added on top of whichever clock applies to your original shares.
The Washington layer
For Washington residents, Section 1202-excluded gain falls outside the Washington capital gains tax base. The gain that is not excluded — post-exchange appreciation, and anything above your cap — is long-term capital gain subject to Washington's 7% tax on gains above the annual standard deduction ($278,000 for tax year 2025, inflation-adjusted), and 9.9% on the portion above $1 million. A large tender payout can also trigger estimated payment obligations. See our Washington State Capital Gains Tax guide.
And looking forward: Washington's 9.9% income tax on household income above $1 million takes effect January 1, 2028, and is likely headed to the November 3, 2026 ballot. The tax remains law, effective January 1, 2028, unless voters repeal it or the courts strike it down — plan as though it arrives on schedule.
What to do if this is you
- Confirm your original shares were QSBS and how the acquisition was structured (the merger agreement's tax section will say whether it was intended as a Section 368 reorganization).
- Establish the exchange-date value of your shares and paper it.
- Run your cap math on the exchange-date built-in gain — not the current value.
- If a sale or tender is coming, model the taxable slice (post-exchange appreciation) and plan the federal and Washington estimated payments.
If you are holding acquirer stock that used to be QSBS and a liquidity event is approaching, schedule a 20-minute call and we can walk through where your shares sit.
This post is general information, not legal or tax advice for your situation. The application of Sections 1202, 351, and 368 to any particular acquisition depends on the deal documents and your specific facts.
