QSBS — Qualified Small Business Stock under IRC §1202 — provides one of the most powerful tax benefits available to founders and early investors: a federal capital-gains exclusion on the sale of qualifying C-corporation stock. For a founder selling in an M&A deal, QSBS can mean excluding millions of dollars of gain from federal tax entirely, which makes it a major driver of structuring and of the stock-vs-asset decision.
The benefit
For stock that qualifies, §1202 allows the holder to exclude capital gain on a sale up to a cap — the greater of $10 million or 10× the holder's basis in the stock (the "per-issuer" limit). Stock acquired after September 27, 2010 generally qualifies for a 100% exclusion of the eligible gain (earlier acquisition dates had 50% or 75% exclusions). The exclusion is per shareholder, per company, so multiple qualifying holders each get their own cap.
A founder with $0 basis selling QSBS could exclude up to $10M of gain; a founder who contributed significant capital could exclude up to 10× that basis if larger.
The qualification requirements
The benefit is generous but the conditions are strict — all must be met:
- C-corporation. The issuer must be a domestic C-corp (not an S-corp, LLC or partnership) — a key reason some companies choose or convert to C-corp status.
- Original issuance. The stock must be acquired directly from the company at original issue (for cash, property or services), not bought from another shareholder.
- Five-year holding period. The stock must be held more than five years before sale.
- Gross-assets test. The company's aggregate gross assets must not have exceeded $50 million at any time up to and immediately after the stock issuance.
- Active qualified business. The company must use at least 80% of its assets in an active qualified trade or business — certain fields are excluded (most professional services, finance, hospitality, farming, etc.).
QSBS as a structuring driver
QSBS strongly influences how a deal is shaped:
- It pushes sellers toward a stock sale, since the exclusion applies to gain on stock — an asset sale would forfeit it. This can flip the usual asset-vs-stock dynamic in the seller's favor.
- It must be verified in diligence — confirming the holding period, original-issuance, gross-assets and active-business tests, since a failure anywhere disqualifies the exclusion.
- Planning techniques (e.g., "stacking" across family members or trusts to multiply the cap, careful timing of the five-year clock) are common, and tax advisers engage early.
Note on recent changes
Congress expanded §1202 in 2025: for QSBS issued after July 4, 2025, the rules add a tiered exclusion for shorter holding periods (partial exclusion at 3 and 4 years, full at 5), raise the per-issuer dollar cap (to $15M, indexed), and lift the gross-assets ceiling (to $75M). Stock issued earlier remains under the prior rules. Because the regime now depends on when the stock was issued, confirming the applicable version is part of QSBS analysis in any deal. (This is general information, not tax advice — QSBS is highly fact-specific and should be confirmed with a tax adviser.)
See also
- Stock purchase — A deal structure in which the buyer acquires the equity of the target entity, taking it whole — assets, liabilities, contracts and history. Generally favoured by sellers.
- Taxable vs tax-free reorganization — The threshold tax-structure question in U.S. M&A: whether the seller recognises gain at closing (taxable) or whether the transaction qualifies for non-recognition under the reorganization rules of Section 368.
- Tax due diligence — The tax-focused workstream of buy-side diligence: federal/state/local income tax exposure, sales-and-use tax, payroll tax, transfer pricing, R&D credits, and the tax history of the target entity.
- Rollover equity — Existing equity that the seller (often the founder or management team) retains in the post-close business rather than cashing out at closing. Standard in PE-backed deals to keep operators incentivised.