Federal Section 1202 QSBS Gain Exclusion Calculator

How this calculator works

IRC § 1202 is the startup founder's superpower. Held for the right amount of time on the right kind of stock issued by the right kind of company, gain on the sale of qualified small business stock (QSBS) is excluded from federal income tax — up to 100% of it. On a $10,000,000 exit at the 100% exclusion rate, a founder owes $0 in federal long-term capital gains tax, $0 in 3.8% Net Investment Income Tax under IRC § 1411(c)(1)(B), and $0 in alternative minimum tax. The savings can exceed $3,000,000 on a single transaction. § 1202 is the most valuable single line item in startup-exit tax planning, and the rules are precise.

This calculator models the federal-pure § 1202 mechanic in a single planning view: the realized gain, the eligibility chain (six tests, any of which can disqualify the entire holding), the per-issuer cap, the excluded gain, the taxable remainder, federal LTCG, NIIT, state tax (with California's notable non-conformance modeled explicitly), and the tax savings vs the no-§-1202 baseline.

The three exclusion eras

IRC § 1202(a) sets the exclusion percentage based on the acquisition date of the stock — not the sale date:

1. 50% exclusion for stock acquired between August 11, 1993 and February 17, 2009 (the original 1993 rate). The non-excluded half is taxed at a special 28% AMT-LTCG rate under IRC § 1(h)(4) rather than the standard 15%/20% LTCG rate, and a portion of the exclusion is an AMT preference item. Economically the worst of the three eras, but still meaningful relief.

2. 75% exclusion for stock acquired between February 18, 2009 and September 27, 2010 (American Recovery and Reinvestment Act of 2009).

3. 100% exclusion for stock acquired on or after September 28, 2010 (Small Business Jobs Act of 2010, made permanent by the PATH Act of 2015). The 100%-excluded gain is NOT an AMT preference, NOT subject to the 3.8% NIIT, and fully shielded from federal income tax. This is the modern, headline-grabbing version of § 1202.

The era is locked at acquisition. Stock issued in 2008 is forever a 50%-era share, no matter when it sells. Stock issued in 2024 is forever a 100%-era share. There is no way to "upgrade" older stock — the only path is to sell and roll into newer QSBS under § 1045 (which carries its own complications).

The per-issuer cap

Under IRC § 1202(b)(1), eligible gain on stock of any single issuer is capped at the greater of:

• $10,000,000 (reduced by gain previously excluded with respect to that issuer in prior years), OR
• 10 × the aggregate adjusted basis of the issuer's QSBS sold during the year.

The 10× basis prong is the founder's relief valve and the investor's reward for putting real capital in. A founder with $0.01 of basis is capped at the $10M floor. A Series A investor who paid $5,000,000 for their shares is capped at $50M. A Series B investor with $20,000,000 of basis is capped at $200M. The cap is per issuer, not per taxpayer — gain on stock of multiple unrelated issuers gets the cap multiplied across them.

The 5-year holding period

§ 1202(a)(1) requires the taxpayer to hold the QSBS for more than 5 years before sale. Stock sold at 4 years and 11 months → exclusion is exactly $0. There is no partial-credit prorate, no good-faith exception, no "substantially complied" defense. This is the single most-blown § 1202 requirement in practice — founders pressured by an acquisition timeline or employees offered an early tender frequently sell at year 4 or year 4.5 and forfeit the entire exclusion.

The only relief is IRC § 1045: sell pre-5-year QSBS and roll the proceeds into other QSBS within 60 days, and the holding period of the original stock tacks onto the replacement. § 1045 fund vehicles have emerged specifically to provide the replacement QSBS within the tight 60-day window. Plan acquisitions with the 5-year clock in mind; resist tender offers in years 3-4 unless the § 1045 rollover plan is in place.

Original issuance — the secondary-market trap

§ 1202(c)(1)(B) requires the taxpayer to have acquired the QSBS directly from the corporation at original issuance (or through an underwriter) in exchange for money, property other than stock, or services rendered. Stock acquired by buying shares from another shareholder — a secondary purchase, an employee's tender, an SPV that holds founder stock, an angel who exits early to another investor — does NOT qualify, even if the issuer is otherwise eligible.

This is the secondary-market trap. The buyer in a secondary transaction holds non-QSBS stock for federal tax purposes, full stop. If you bought into a startup on the secondary market (including via Forge Global, EquityZen, or any other secondary platform), you do not have QSBS regardless of how long you hold and regardless of the issuer's underlying eligibility.

The major carve-outs under § 1202(h) preserve QSBS character: gifts (the donee inherits QSBS status and the donor's holding period), transfers at death (with some uncertainty about holding-period tacking), and certain tax-free reorganizations under §§ 368, 351, and 1045.

The $50M gross-assets test

IRC § 1202(d)(1) requires the issuing corporation's aggregate gross assets to NOT exceed $50,000,000 at any time from August 10, 1993 through the moment immediately after the issuance of the stock in question. Gross assets are measured at adjusted basis (with FMV for property contributed in exchange for the stock being issued).

The test is at-issuance only. A company that crosses the $50M ceiling AFTER your stock was issued does not retroactively disqualify your shares. This is why early-round investors in successful startups often have QSBS while later-round investors in the same company do not: your Series A shares were QSBS at $30M post-money, but the Series C shares issued at $200M post-money were not. Late-stage investors and growth-equity rounds frequently don't qualify because the issuer has already exceeded $50M by the time of investment.

Active business and ineligible businesses

§ 1202(e) requires at least 80% of the corporation's assets (by value) to be used in the active conduct of a qualified trade or business during substantially all of the taxpayer's holding period. § 1202(e)(3) excludes specific categories regardless of asset deployment:

• Services in health, law, engineering, architecture, accounting, actuarial science, performing arts, consulting, athletics, financial services, or brokerage. Note: § 1202's ineligible-business list is broader than § 199A's SSTB list — engineering and architecture ARE excluded for § 1202 even though they are NOT SSTBs for § 199A.
• Banking, insurance, financing, leasing, investing, or similar businesses.
• Farming (including timber).
• Mining, oil-and-gas, and other businesses involving extraction of minerals subject to depletion.
• Hotels, motels, restaurants, or similar establishments (hospitality).

Tech startups, biotech, manufacturing, consumer products (most), and software businesses qualify. Professional services firms, real-estate operating businesses, restaurants, hotels, and most service-heavy businesses do NOT.

Worked example 1 — founder, 100% exclusion, full shelter

A founder acquires 10,000,000 shares at $0.0001/share ($1,000 total basis) on 2018-01-01. Sells all shares on 2026-01-01 for $5,000,000. The company is a Delaware C-corp building enterprise SaaS, with gross assets of $15M at issuance and 80%+ of assets in the qualified active business throughout.

• Holding period: 8 years ✓ (above the 5-year minimum)
• C-corp ✓ · Original issuance ✓ · Active qualified business ✓ · Gross assets ≤ $50M ✓
• Acquisition era: post-2010 → 100% exclusion
• Realized gain: $5,000,000 − $1,000 = $4,999,000
• Per-issuer cap: max($10,000,000, 10 × $1,000) = $10,000,000
• Eligible gain: min($4,999,000, $10,000,000) = $4,999,000
• Excluded gain: $4,999,000 × 100% = $4,999,000
• Taxable gain: $0
• Federal LTCG: $0 · NIIT: $0 · State (assuming FL/TX/no-tax state): $0
• Total federal tax: $0. Total state tax: $0.

The founder walks away with $5,000,000 of cash and owes nothing. The baseline tax (if § 1202 didn't exist) would have been ~$1,190,000 (20% LTCG + 3.8% NIIT × $4,999,000). § 1202 saved the founder over a million dollars.

Worked example 2 — founder, $15M exit, $10M floor binds

Same founder as Example 1, but sells for $15,000,000 instead of $5M.

• Realized gain: $15,000,000 − $1,000 = $14,999,000
• Per-issuer cap: max($10,000,000, 10 × $1,000) = $10,000,000
• Eligible gain: min($14,999,000, $10,000,000) = $10,000,000
• Excluded gain: $10,000,000 × 100% = $10,000,000
• Taxable gain: $14,999,000 − $10,000,000 = $4,999,000
• Federal LTCG (20%): $999,800
• NIIT (3.8%): $189,962
• State (FL): $0
• Total tax: $1,189,762 on a $15M exit. Effective rate: ~7.9% on the full realized gain.

The $10M floor binds because the founder's basis is negligible — the 10× basis cap would be $10,000 (10 × $1,000), well below the floor. Compare to the no-§-1202 baseline of $14,999,000 × 23.8% ≈ $3,569,762 — § 1202 saved the founder approximately $2,380,000.

Worked example 3 — investor, $50M exit, 10× basis cap binds

A Series A investor wires $2,000,000 for stock issued on 2018-01-01 by the same Delaware C-corp ($15M gross assets at issuance). On 2026-01-01 the company is acquired and the investor receives $50,000,000 for their position.

• Realized gain: $50,000,000 − $2,000,000 = $48,000,000
• Per-issuer cap: max($10,000,000, 10 × $2,000,000) = $20,000,000
• Eligible gain: min($48,000,000, $20,000,000) = $20,000,000
• Excluded gain: $20,000,000 × 100% = $20,000,000
• Taxable gain: $48,000,000 − $20,000,000 = $28,000,000
• Federal LTCG (20%): $5,600,000
• NIIT (3.8%): $1,064,000
• State (assume non-CA): $0
• Total tax: $6,664,000 on a $50M exit. Effective rate: ~13.9% on the full realized gain.

The 10× basis prong kicks in: the investor's $2M of basis lifts the cap from $10M (the floor) to $20M (10 × $2M). $20M of gain is fully excluded; the remaining $28M is taxed normally. Compare to the no-§-1202 baseline of $48,000,000 × 23.8% ≈ $11,424,000 — § 1202 saved the investor approximately $4,760,000.

Worked example 4 — same founder, sold at 4 years → ZERO exclusion

Same founder as Example 1, but sells on 2022-01-01 — exactly 4 years after acquisition.

• Holding period: 4 years ✗ (below the 5-year minimum)
• INELIGIBLE. Eligibility reason: holding period of 4.00 years is less than the 5-year minimum under § 1202(a)(1).
• Excluded gain: $0
• Taxable gain: $4,999,000 (the full realized gain)
• Federal LTCG (20%): $999,800
• NIIT (3.8%): $189,962
• Total tax: $1,189,762 — vs $0 if the founder had waited 12 more months.

The 5-year cliff is unforgiving. If the founder couldn't wait (acquisition timeline forced the sale), a § 1045 rollover into other QSBS within 60 days would have preserved holding-period tacking and salvaged the eventual exclusion. § 1045 funds exist specifically for this scenario.

Worked example 5 — secondary purchaser → ZERO exclusion

A late-joining employee buys 100,000 shares from a departing co-worker in a secondary transaction on 2019-01-01 for $50,000 ($0.50/share). The shares are part of the same Delaware C-corp issued in 2018. On 2026-01-01 the company is acquired and the employee receives $5,000,000 for the position.

• Holding period: 7 years ✓
• C-corp ✓ · Active qualified business ✓ · Gross assets ≤ $50M ✓
• Original issuance: ✗ — these shares were bought from another shareholder, not from the corporation.
• INELIGIBLE. Eligibility reason: stock was not acquired at original issuance under § 1202(c)(1)(B).
• Excluded gain: $0
• Taxable gain: $5,000,000 − $50,000 = $4,950,000
• Federal LTCG (20%): $990,000
• NIIT (3.8%): $188,100
• Total tax: $1,178,100.

The secondary-market trap. The original-holder's 2018 shares would have been fully QSBS; the same shares in the secondary purchaser's hands are not. This is the single most-overlooked § 1202 trap among employees who join via secondary tender offers.

California non-conformance

State tax treatment of § 1202 gain varies. Most states with income taxes that conform to the Internal Revenue Code by reference also conform to § 1202 (New York, Illinois, Massachusetts, Georgia, New Jersey, Virginia, etc.). States with no income tax (Florida, Texas, Tennessee, Washington, Nevada, South Dakota, Wyoming, Alaska) effectively conform.

California is the notable non-conformer. Cal. Rev. & Tax Code § 18152.5 was struck down by the California Supreme Court in Cutler v. Franchise Tax Board (2012) and formally repealed in 2013. California now taxes the full realized gain at ordinary income rates (top rate 13.3%) regardless of federal exclusion. A California founder with a $10M federal-excluded gain still owes ~$1,330,000 in California state tax.

Some California founders re-domicile to Nevada, Texas, or Florida well before a sale to avoid this — but the California Franchise Tax Board scrutinizes domicile changes aggressively in the year of a known liquidity event. Domicile changes need to happen years ahead of the exit, with full evidence (driver's license, voter registration, primary residence, ties to the state) of a real and permanent move. The calculator's "state conforms" toggle models this — set it to FALSE for California and supply the relevant state rate.

NIIT and AMT exclusion

IRC § 1411(c)(1)(B) explicitly excludes § 1202-excluded gain from net investment income — so the excluded portion is never subject to the 3.8% NIIT. On a $10M fully-excluded sale, the NIIT savings alone are $10M × 3.8% = $380,000 — meaningful relative to the headline LTCG savings.

For post-2010 (100%-era) stock, the excluded gain is also fully excluded from the alternative minimum tax — no AMT preference treatment under the post-PATH-Act version of § 56(b)(1)(C). For pre-2009 (50%-era) stock, a portion of the excluded gain IS an AMT preference, and the non-excluded half is taxed at the special 28% AMT-LTCG rate under § 1(h)(4) — economically less attractive than modern 100%-era treatment.

§ 1045 rollover — buying time when 5 years isn't there

IRC § 1045, enacted by the Taxpayer Relief Act of 1997, lets a taxpayer defer recognition of gain on QSBS sold before the 5-year mark by rolling the sale proceeds into other QSBS within 60 days of the original sale. The replacement QSBS must itself qualify under all the § 1202 tests, and the holding period of the original QSBS tacks onto the replacement stock for purposes of the eventual § 1202 5-year test.

§ 1045 is essential planning for founders or early employees whose stock is being acquired before the 5-year mark — without § 1045, the entire exclusion would be lost; with § 1045, the eventual sale of the replacement QSBS (held for the combined original + replacement period beyond 5 years) qualifies for the full § 1202 exclusion. The 60-day window is hard; finding replacement QSBS within 60 days is the practical constraint, but § 1045 fund vehicles have emerged in recent years specifically to provide this option.

Gifting and QSBS stacking

Under IRC § 1202(h), gifts of QSBS preserve QSBS character in the donee's hands AND tack the donor's holding period — the donee inherits the QSBS status, the holding-period clock, and (importantly) their own $10M-or-10×-basis per-issuer cap. This enables "QSBS stacking" or "QSBS packing": a founder facing a large exit can gift QSBS to family members, non-grantor trusts, or charitable entities BEFORE the sale, multiplying the per-issuer cap across multiple taxpayers.

Each donee has their own $10M floor. Five non-grantor trusts with $10M each yields $50M of excluded gain (vs $10M for the founder alone). This is a real, IRS-recognized strategy with good case law support, but it requires (a) completion of the gift well before sale, (b) careful donor-intent documentation, and (c) the gift cannot have been part of a pre-arranged sale plan (step-transaction doctrine). Founders contemplating a large exit should engage § 1202 counsel 12-24 months ahead of the sale to set up the stacking structure properly.

Common errors

• Assuming any startup stock qualifies. Confirm C-corp status, original-issuance documentation, gross-assets figures at issuance, and active-qualified-business compliance for every holding.
• Missing the $50M gross-assets test. Late-stage rounds and growth-equity investments frequently fail this — confirm the company's balance sheet at the issuance date.
• The secondary-market trap. Employees who join via secondary tender offers, SPV holders, and investors who buy from earlier shareholders do not have QSBS regardless of how long they hold.
• Selling at year 4 or year 4.5 without a § 1045 rollover plan. The 5-year cliff is unforgiving.
• Forgetting California (and any other non-conforming state). The federal exclusion does not flow through to state tax in non-conforming jurisdictions.
• Treating engineering or architecture as eligible because they aren't SSTBs under § 199A. § 1202's ineligible-business list is BROADER than § 199A's — engineering and architecture ARE excluded under § 1202(e)(3) even though they are NOT SSTBs.
• Failing to set up gifting/stacking structures well before sale. Gifts made in the same window as a known sale are vulnerable to the step-transaction doctrine.

Statute citations

• IRC § 1202(a) — exclusion rate (50% / 75% / 100% by acquisition date)
• IRC § 1202(b)(1) — per-issuer cap (greater of $10M or 10× basis)
• IRC § 1202(c) — QSBS definition (5-year hold, original issuance, eligible C-corp)
• IRC § 1202(d)(1) — $50M gross-assets ceiling
• IRC § 1202(e) — active business test and ineligible-business list
• IRC § 1202(h) — carryover for gifts, death, certain reorganizations
• IRC § 1045 — 60-day rollover and holding-period tacking
• IRC § 1411(c)(1)(B) — NIIT exception
• IRC § 1(h)(4) — 28% AMT-LTCG rate on pre-2009 50%-era stock
• Treas. Reg. § 1.1202-0 through § 1.1202-2 — operational rules
• IRS Form 8949 and Schedule D — capital-gain reporting
• Pub. L. 103-66 (1993) — enacted § 1202
• Pub. L. 111-5 (ARRA 2009) — 75% exclusion
• Pub. L. 111-240 (SBJA 2010) — 100% exclusion
• Pub. L. 114-113 (PATH 2015) — made 100% permanent

Important caveats

This is a planning tool, not legal or tax advice. It does not model the § 1045 60-day rollover deferral (the user supplies a single sale; if rollover is in play, run the calculator on the eventual taxable event), multi-year sales of the same issuer's stock against the rolling $10M cap (the user supplies a single year), or the precise AMT preference mechanics for pre-2009 50%-era stock (the calculator defers to the user-supplied LTCG rate; override to 0.28 for the AMT-LTCG rate). State conformity is modeled as a binary toggle plus rate input; consult specific state law for partial-conformity edge cases. Confirm every eligibility test with tax counsel before claiming the exclusion — the IRS audits large § 1202 exclusions aggressively and the documentation burden falls on the taxpayer.