A taxpayer other than a corporation who sells qualifying QSBS held for more than six months may elect Section 1045 deferral by purchasing replacement QSBS during the 60-day period beginning on the sale date. Deferred gain reduces replacement basis. Eligibility, replacement cost, and a valid election determine the result; the rollover does not itself guarantee a later exclusion.
Updated September 10, 2026.
This post is part of my complete guide to QSBS and Section 1202.
**Hypothetical:** Sarah acquired qualifying original-issue stock in a SaaS C corporation in July 2023 for $500,000. Three years later, she receives an $8 million offer for all her shares. Assume no selling expenses or later basis adjustments.
Sarah’s statutory acquisition date is on or before July 4, 2025, so the newer three- and four-year exclusion tiers do not apply. Her three-year sale does not qualify for Section 1202 exclusion. At an assumed combined federal long-term capital-gain and NIIT rate of 23.8%, her $7.5 million gain would produce $1.785 million in federal tax before a rollover or other applicable relief. Actual rates and state taxes require separate analysis.
She wants to evaluate whether reinvesting sale proceeds is appropriate before accepting the deal.
Section 1045 is one potential alternative to current recognition of the gain.
What Is a Section 1045 Rollover?
Section 1045 can defer eligible gain through a timely purchase of qualifying replacement stock and a valid election. Full deferral requires sufficient replacement cost; a partial reinvestment can leave gain recognized now. The provision does not defer amounts treated as ordinary income.
Deferral preserves capital for a new investment while embedding the deferred gain in reduced replacement basis. The next investment can lose value, and the eventual sale may be taxable. Compare those risks with paying tax and retaining or diversifying the proceeds.
The Five Requirements
One threshold point first: the rollover is available only to taxpayers other than corporations (IRC § 1045(a)) — individuals, trusts, and estates qualify, and partnerships have their own rollover rules under Reg. § 1.1045-1. A C corporation selling stock it holds cannot use Section 1045. From there, you must meet all five of these:
1. You must have held the original QSBS for more than six months. More than six months is required. For this test, §1045(b)(4)(A) disregards holding-period tacking under §1223; a rapid second rollover cannot rely solely on the first investment’s age.
2. You must reinvest in replacement QSBS within 60 days of the sale. The 60-day period begins on the sale date. Do not assume a discretionary extension is available. Rev. Proc. 2018-58 identifies §1045 replacement purchases as acts potentially covered by specified disaster or combat-zone postponements; eligibility and the applicable relief must be checked. The revenue procedure itself grants no disaster postponement.
**3. The replacement stock must meet the applicable QSBS rules.** Confirm original issuance, C-Corp status, the applicable gross-assets ceiling and asset history, and business eligibility. Section 1045(b)(4)(B) applies Section 1202(c)(2) to the replacement stock using only its first six months of holding for the rollover test. A later Section 1202 exclusion separately requires C-Corp and active-business compliance during substantially all of the replacement holding period. The six-month rule is not permission to ignore the business after that period if a later exclusion is the goal. See Section 1045 and Section 1223(13).
**4. Full deferral requires reinvestment of the entire amount realized, not merely the gain.** Recognized gain is generally the smaller of realized gain or the positive excess of amount realized over qualifying replacement cost, subject to the statutory rules. With $8 million of proceeds and $500,000 basis, reinvesting $8 million can defer all $7.5 million of gain; reinvesting $7.5 million leaves $500,000 recognized.
5. The replacement stock must be acquired for "cost." The replacement acquisition must be a purchase under §1045(b)(2), with a cost basis before the rollover adjustment. A cash subscription is the straightforward example. Do not assume a service grant or carryover-basis property contribution satisfies this test.
Holding Period Tacking: The Key Benefit
Related → See eight useful elements of a QSBS factual record for the replacement stock — the rollover doesn't help if the new shares can't be substantiated. The replacement stock's qualification also has to be maintained going forward — an annual attestation practice like QSBS Sentinel™ covers the new position from day one.
For the later §1202 holding-period test, §1223(13) generally carries the old holding period into the replacement stock. It expressly excludes §1202(c)(2)(A), however: the old issuer’s years do not count toward the replacement issuer’s active-business compliance period. The separate §1045 six-month test also disregards §1223 tacking.
Sarah’s original three-year holding period generally tacks to qualifying replacement stock for the later Section 1202 holding-period test. She must still satisfy the applicable acquisition-date regime, replacement-company requirements, and eligible-gain limits; a rollover is not a promise of exclusion.
Sarah’s original stock was acquired before July 5, 2025. Under §1202(a)(6)(B), the statutory acquisition date accounts for applicable §1223 tacking; buying replacement shares after that date does not itself move her into the new tiers.
For Sarah’s acquisition date, the stock must be held for more than five years for exclusion. Later acquisition regimes have different thresholds; consult the linked QSBS guide.
If Sarah satisfies the applicable holding period—more than five years for her pre-change acquisition date—and the replacement stock meets the remaining requirements and gain limits, exclusion may be available on a later sale. Reaching an anniversary alone does not establish the result.
The Basis Adjustment
Deferred gain reduces the replacement stock’s basis. Keep a schedule showing purchase cost, gain deferred, and the resulting adjusted basis.
Sarah's math:
- Original QSBS cost basis: $500,000
- Sale price: $8,000,000
- Gain: $7,500,000
- Amount reinvested in new QSBS: $8,000,000
- Basis in replacement QSBS: $8,000,000 - $7,500,000 = $500,000
Sarah’s $8 million replacement purchase has $500,000 basis after deferring $7.5 million. A later sale computes gain using that adjusted basis. The amount recognized then depends on sale proceeds and any available exclusion or further qualifying rollover; the deferred amount is not a fixed future tax bill.
The Angel Investor Play
An angel investor can also consider Section 1045. Moving proceeds into another startup changes the investment exposure; it does not necessarily reduce portfolio risk.
**Second hypothetical:** David bought qualifying QSBS in July 2024 for $100,000 and sells all of it in July 2026 for $600,000. His holding period exceeds six months but does not satisfy the more-than-five-year exclusion requirement for that acquisition date.
David sells for $600,000, then reinvests the full $600,000 in proceeds in another qualifying startup within 60 days. His $500,000 gain is deferred. His holding period tacks. Because his holding clock generally continues rather than resetting, he stays on track toward the five-year mark; whether and how the Section 1202 exclusion ultimately reaches the deferred gain on a later sale depends on his specific facts and should be confirmed with counsel.
Washington State Implications
Federal gain deferred under §1045 generally does not enter Washington’s federal-recognition-based capital-gains starting point that year. For taxable Washington capital gains, RCW 82.87.040 imposes 7%, plus 2.9% on Washington capital gains exceeding $1 million—not an additional 9.9% on top of 7%. Calculate the statutory base after applicable adjustments and deductions. See the Washington income-tax guide for the separate scheduled 2028 tax and credit coordination.
The 60-Day Trap
A replacement purchase must occur within the statutory window. Identifying an investment or signing a preliminary term sheet does not by itself establish a qualifying stock purchase.
Investigate replacement investments before the sale where practical, and document the actual purchase and issuance. A term sheet does not stop the 60-day clock. Evaluate the investment on its merits as well as its tax eligibility.
For the complete Section 1045 playbook with advanced strategies, checklists, and worked scenarios, get the Section 1045 QSBS Rollover Guide.
Section 1045 in Plain English
Section 1045 is a potential deferral provision for eligible QSBS sales. It is not limited to sales before five years, and it is not always needed when Section 1202 can exclude gain. Compare the applicable exclusion with the cost and risk of reinvesting proceeds.
The statutory holding-period and basis rules preserve aspects of the original investment’s tax history. They do not guarantee the replacement company qualifies or that future gain will be excluded.
Planning Strategies for Founders Expecting Early Exits
Identify and investigate replacement investments before the sale. Confirm issuance, purchase cost, corporate status, asset history and the actual business plan.
Deferred payment does not extend ownership. An earnout or seller note may affect recognition under the installment rules, but a completed stock sale ends the holding period of the stock sold. Do not count years waiting for payment toward §1202. See IRS Publication 537.
A reorganization has different rules. Receiving buyer stock in a qualifying §368 transaction can preserve holding periods; it does not necessarily restart them. Section 1202(h)(4) may preserve QSBS treatment for otherwise nonqualified replacement stock, subject to its exchange-date gain limitation and other conditions. See the acquisition guide.
A partial sale leaves the unsold position’s holding period running. Evaluate the sold shares separately, with their actual basis and acquisition dates.
Who Uses Section 1045 — and When
Common situations in which an investor might evaluate Section 1045 include:
- **Secondary sales:** Evaluate the actual shares sold, original issuance, acquisition date, and more-than-six-month requirement.
- **Founder liquidity:** A qualifying partial sale may permit a rollover for the sold shares; the unsold position is analyzed separately.
- **Portfolio reinvestment:** Successive qualifying rollovers can continue deferral, but each purchase and sale must independently meet the applicable rules. Reinvestment does not guarantee investment returns.
Successive rollovers can defer gain, but each must independently qualify. Keep separate records for each purchase date, deferred gain and replacement basis; do not restart the §1202 clock or use tacking to bypass §1045’s more-than-six-month sale requirement.
The Section 1045 Process Step by Step
- Confirm the sold shares qualify and satisfy the more-than-six-month requirement.
- Record the sale date, amount realized, basis and gain.
- Purchase eligible replacement QSBS during the statutory 60-day period and document the replacement issuer’s business and asset tests.
- Calculate recognized and deferred gain from proceeds and replacement cost, not gain alone.
- Make the election and report it on Form 8949 and Schedule D using the applicable instructions. A timely original return can permit a corrective election on an amended return within six months of the unextended due date under §301.9100-2. See Publication 550, “Rollover of Gain.” This filing relief does not extend the replacement-purchase window.
Head-to-Head: Section 1045 vs. Section 1202
| Question | §1202 | §1045 |
|---|---|---|
| Result | Exclusion of eligible gain | Deferral through reduced replacement basis |
| Holding period | More than five years for pre-change acquisition dates; 3/4/5-year tiers for qualifying post-change acquisitions | More than six months, without §1223 tacking for this test |
| Reinvestment | Not required | Replacement purchase during the 60-day period |
| Limits | Acquisition-date, percentage and per-issuer gain limits | Deferral depends on amount realized and eligible replacement cost |
Check the QSBS guide for the acquisition-date rules and historical exclusion percentages.
When to Use Section 1202 Alone
Section 1202 alone may be sufficient when the stock meets all requirements and the applicable exclusion percentage and remaining limit cover the gain. Holding stock for more than five years does not by itself establish a 100% exclusion for every historical acquisition date.
Suppose you founded a company in 2020 and received stock with a basis of $10,000. In 2026, six years later, you sell for $8 million. You've held for more than five years, the gain is well under $10 million, and assuming the stock qualifies as QSBS the entire way through, you exclude the entire $7,990,000 gain. Federal tax: zero.
A tax exclusion is one consideration in an exit decision. It should be weighed alongside price, liquidity, business risk, and the shareholder’s objectives.
When to Use Section 1045 Alone
Suppose you sell at month 18 for $3.5 million with $500,000 basis: the gain is $3 million. Reinvesting all $3.5 million in qualifying replacement stock can defer the full gain. Reinvesting only $3 million leaves $500,000 recognized under §1045. Any separate §1202 exclusion requires its own analysis.
The deferred amount reduces replacement basis. A later exclusion depends on the applicable tacked holding period and the replacement stock’s qualification and gain limits.
When to Evaluate Both Together
Do not assume you can first exclude 50% or 75% and then eliminate the entire tax bill by reinvesting only the unexcluded gain. The §1045 calculation uses amount realized and replacement cost. Coordination with §1202 requires a transaction-specific calculation of recognition, eligible gain, exclusion and basis. Model the alternatives before committing proceeds; the two benefits cannot be assigned to dollars twice.
The Serial Entrepreneur Playbook
A founder who acquired QSBS in January 2024 and sells in July 2025 can potentially roll the proceeds into qualifying stock of a new venture. The old holding period generally tacks for the later exclusion test. For that pre-change acquisition date, the combined hold must exceed five years; exactly five years is insufficient. The new company must satisfy its own active-business requirements during the replacement holding period.
Success does not make the exclusion automatic. Keep the original issuance and acquisition records, rollover election, basis schedule and replacement-company substantiation together.
Decision Flowchart
- Potential §1202 exclusion: determine acquisition date, actual holding period, eligible-gain limit and percentage.
- Potential §1045 deferral: establish QSBS status, a more-than-six-month hold without §1223 tacking for that test, a timely replacement purchase and a valid election.
- Both potentially available: compute their interaction; do not merely reinvest the unexcluded gain.
- Neither available: calculate taxable gain and other applicable rules without assuming a later transaction repairs this sale.
Section 1045 vs. 1031 Exchanges: Key Differences
Both provisions can postpone gain, but they govern different property and use different procedures. Section 1045 requires qualifying replacement stock; the real-estate exchange analogy does not supply its deadlines or election rules. Deferral can have value even if a later §1202 exclusion is unavailable.
The Basis Trap: What Most Guides Miss
Reinvesting $500,000 while deferring $400,000 leaves $100,000 replacement basis. A later $1 million sale would therefore produce $900,000 gain before any available exclusion. The adjusted basis can also affect §1202’s 10-times-basis alternative limit. Model the cap and excluded amount separately; reduced basis does not itself create an exclusion.
Frequently asked questions
Must I reinvest proceeds or only gain?
To defer all gain under §1045, eligible replacement cost must cover the full amount realized. Reinvesting only the gain can leave current recognized gain.
Does a rollover restart the QSBS clock?
The prior holding period generally tacks for a later exclusion. It does not satisfy the replacement issuer’s active-business period or bypass §1045’s separate six-month test.
Can I fix an omitted election?
Potentially. Publication 550 describes an amended-return election within six months of the unextended due date when the original return was timely filed. That relief does not extend the replacement-purchase period.
For help evaluating a rollover before the sale, book a 20-minute call.
This article is general information, not legal or tax advice.
