What Is QSBS? The Complete Guide to Section 1202

Qualified Small Business Stock — QSBS, codified at IRC §1202 — lets founders, early employees, and investors exclude a large share of their gain from federal capital-gains tax when they sell stock in a qualifying C-corporation. After the One Big Beautiful Bill Act (OBBBA), the exclusion is bigger and reaches more companies than ever. For anyone holding startup equity heading into a liquidity event, it is the single largest tax opportunity on the table.

The stakes, in one number: a fully qualifying §1202 position on a $10M gain saves roughly $2.4M in federal tax (at the 23.8% rate you'd otherwise pay). On larger positions, and when you stack the exclusion across trusts and family, the savings run well into eight figures. This is a statute Congress wrote to reward startup investment — not a loophole.

What QSBS actually is

Section 1202 excludes gain on the sale of "qualified small business stock" from federal income tax, provided the stock and the holder meet a series of tests. The stock must come from a domestic C-corporation that was small enough at issuance, in a qualifying line of business, and you must have acquired it at original issuance and held it long enough. Meet all of that, and a defined slice of your gain comes out entirely federally tax-free.

The reason so few people use it is that qualification is decided years before the sale — and nobody at your company is responsible for telling you whether you qualify. By the time the tender offer or acquisition lands, the facts that determine eligibility are already locked in.

What OBBBA changed (effective July 4, 2025)

OBBBA materially expanded §1202 for stock issued after July 4, 2025. Stock issued on or before that date still follows the prior rules. The issuance date of your specific shares is what controls which rule set applies.

Rule	Stock issued ≤ July 4, 2025	Stock issued after July 4, 2025
Company gross assets at issuance	≤ $50M	≤ $75M (inflation-adjusted from 2027)
Minimum holding period for any exclusion	5 years (100% only)	3 years (tiered — see below)
Per-issuer exclusion cap	Greater of $10M or 10× basis	Greater of $15M or 10× basis (inflation-adjusted from 2027)
Rate on the unexcluded portion	n/a (0% at 5 years)	28% at the 3- and 4-year tiers; 0% at 5+ years

The post-OBBBA tiered exclusion

For stock issued after July 4, 2025, the all-or-nothing 5-year cliff becomes a ramp:²

3 years held → 50% excluded. The other 50% is taxed at 28%.
4 years held → 75% excluded. The remaining 25% is taxed at 28%.
5+ years held → 100% excluded. Zero federal tax on the qualifying amount.

The 28% rate on the unexcluded portion is higher than the 23.8% you'd pay on ordinary long-term gain — so the 3- and 4-year tiers are a partial benefit, not a free lunch. If you can reach the 5-year mark, do. Our exclusion calculator shows the difference at each tier for your numbers.

The two caps: $15M or 10× basis

The exclusion is capped per taxpayer, per issuer, at the greater of two figures:

$15,000,000 (post-OBBBA dollar cap), or
10× your adjusted basis in the stock.

For most employees the $15M figure governs, because their basis (an option exercise price) is tiny. For investors who put real capital in, the 10×-basis alternative is the bigger lever: a $4M investment supports up to $40M of excluded gain. Gain above whichever cap applies is ordinary long-term capital gain.

Who can claim QSBS

Founders holding their original C-corp shares.
Early employees who exercised options — especially those who early-exercised and filed an 83(b) election, which starts the clock at exercise.
Angel, seed, and venture investors who bought stock directly from the company at original issuance.
Fund LPs and trusts — the exclusion can pass through partnerships and be multiplied across non-grantor trusts (see stacking).

What does not qualify: shares bought on a secondary market, public-market purchases after IPO, and stock in LLCs, S-corps, or partnerships (unless and until properly converted to a C-corp before issuance).

The 5-year clock and Section 1045 rollovers

The holding period is the rule that trips up the most people. The clock starts when you acquire the stock at original issuance — for early-exercised options with a timely 83(b) election, that's the exercise date, often years before vesting completes.

If a tender offer or acquisition forces a sale before your hold matures, IRC §1045 lets you roll the proceeds into new QSBS within 60 days and carry over your original holding period. It is the emergency exit that preserves the exclusion when the timing doesn't cooperate — but the window is short and the replacement stock has to qualify, so it is not a do-it-yourself maneuver.

State conformity: not everyone honors it

Most states follow the federal exclusion, but several do not. California is the big one — it taxes the full gain at up to 13.3% even when it's federally excluded. New Jersey and Pennsylvania also diverge. The federal benefit still dominates, but for a large position the state piece is worth real planning, including residency and timing decisions made before the sale.

Why this needs a specialist

Every lever that determines your QSBS outcome — verifying eligibility, starting the clock, stacking across trusts, deciding whether to §1045 — has to be pulled before the liquidity event. After the deal closes, the facts are fixed. A fee-only advisor who does this work coordinates with your tax counsel to confirm eligibility and sequence the moves while they're still available.

Find out if your stock qualifies — before you sell

The decisions that determine your §1202 outcome happen years before liquidity. Get matched with a fee-only advisor who has run this analysis for founders, employees, and investors. No obligation.

Sources

Post-OBBBA rules apply to stock issued after July 4, 2025; earlier issuances follow the prior $10M / $50M / 5-year regime. Eligibility is fact-specific — confirm with qualified tax counsel before relying on the exclusion.