Section 1045 Rollover: Preserving QSBS When You Sell Before 5 Years

You hold QSBS. A tender offer or acquisition closes before your 5-year clock runs out. Without a plan, you lose the §1202 exclusion and owe capital-gains tax on the full gain. Section 1045 — the "QSBS rollover" — lets you defer that gain by reinvesting in a new qualifying company within 60 days, preserving the path to a full tax-free exit. The 60-day window is the hardest constraint in startup tax planning: there are no extensions, and the replacement stock must be from a company that already meets all the QSBS tests at the time you invest.

What Section 1045 does — and doesn't do

§1045 is a deferral provision, not an exclusion. It allows an eligible taxpayer who sells QSBS before reaching the §1202 holding period to roll the gain into replacement QSBS without recognizing income — as long as the reinvestment happens within 60 days.¹

The deferred gain doesn't disappear. It reduces the tax basis of the replacement stock. When you eventually sell the replacement stock, the deferred gain comes back into the calculation. But — and this is the whole point — if the replacement stock itself qualifies for §1202, and your combined holding period (original + replacement) hits the 5-year threshold, that deferred gain can be excluded under §1202 at the final sale.

The practical path: forced sale of Company A at year 4 → §1045 rollover into Company B → hold Company B to year 5+ → full §1202 exclusion on both the deferred gain and any new Company B gain, up to the cap.

When you need it

The most common trigger is a company being acquired or running a tender offer before the 5-year clock runs. The timeline that matters isn't the company's age — it's when your specific shares were issued to you. A founder who received stock at incorporation has a different clock than an employee who exercised options in Year 3. And different grant tranches can have different clocks.

Other situations where §1045 matters:

• Secondary sale opportunity (tender offer, direct secondary) when you're at 3.5 or 4 years
• IPO lockup expires and you want to sell, but you're just under 5 years
• Company asset sale structured as a stock sale, forcing recognition before the clock runs
• Early-stage investor who wants to redeploy capital into a new seed position without triggering tax

The requirements — original stock

To roll under §1045, the stock you're selling must meet all of these:¹

• Qualifies as QSBS — passes all the §1202 company-level and shareholder-level tests (domestic C-corp, gross assets ≤$75M post-OBBBA, active business, original issuance, non-corporate holder). See the eligibility checklist.
• Held more than 6 months — you must have held the stock for at least 6 months at the time of sale. Early-stage secondaries in the first half-year don't qualify.
• Eligible holder — the selling taxpayer must be an individual, partnership, or S-corporation. A C-corporation holding the stock cannot use §1045.

The requirements — replacement stock

The replacement stock must also qualify as QSBS in its own right at the time you acquire it:²

• Domestic C-corporation — the replacement issuer must be a C-corp at the time you invest.
• Gross assets ≤ $75M — measured at the time the replacement company issues your shares (post-OBBBA; $50M for companies that issued the stock on or before July 4, 2025).
• Active qualified business — not in an excluded service field.
• Original issuance — you must acquire the replacement shares directly from the company, not on a secondary market.
• Acquired within 60 days — the replacement purchase must close within 60 days of the original sale. The clock starts on the sale date, not receipt of proceeds.

The 60-day window — how strict is it?

Completely strict. The IRS has not provided any extension mechanism for §1045. The statute is written as a hard deadline; if day 61 passes without a closed investment in qualifying replacement QSBS, the rollover is gone and the gain is recognized in full for the year of sale.¹

What this means in practice:

• Start identifying replacement companies before the triggering sale closes — ideally months before, once a liquidity event is reasonably foreseeable.
• Have term sheets executed, due diligence done, and legal docs in progress so you can close immediately after the sale.
• Work with counsel who has done §1045 closings before — the documentation requirements (board approval for original issuance, representations on gross assets and active-business test) take time that the 60-day window doesn't have.
• If you're selling in a deal that closes on a specific date, the 60-day clock starts on closing, not on wire receipt. Confirm the exact date with the acquiring company's legal team.

How the math works: basis and holding period

Two mechanics carry over from the original QSBS into the replacement stock:

Reduced basis

The deferred gain reduces your basis in the replacement stock. If you buy replacement QSBS for $5M and defer $4M of gain from the sale of the original stock, your tax basis in the replacement stock is $5M − $4M = $1M.¹ This means a larger gain on the eventual sale of the replacement stock — but if that sale qualifies for §1202, the larger gain is also what gets excluded.

Example: you sell Company A shares with $0.5M basis for $8M (a $7.5M gain). You reinvest $8M in Company B QSBS. Your basis in Company B is $8M − $7.5M = $0.5M. If Company B goes to $25M and you sell at the 5-year mark, your gain is $24.5M. The §1202 cap (greater of $15M or 10× basis = 10 × $0.5M = $5M — so $15M wins) excludes $15M of that, and the remaining $9.5M is taxable as ordinary long-term capital gain.

Tacked holding period

For the purpose of the §1202 5-year holding requirement, your holding period in the replacement stock is deemed to include the period you held the original stock.² If you held Company A for 4 years and 3 months, you need only 9 more months of holding Company B to hit the 5-year threshold and qualify for the §1202 exclusion.

This tacking applies only to the §1202 holding-period test. For other purposes — such as determining which OBBBA exclusion schedule applies — the original acquisition date of the original stock governs.

OBBBA and the exclusion schedule

OBBBA (effective July 4, 2025) introduced tiered exclusion percentages for stock issued after that date: 50% at 3 years, 75% at 4 years, 100% at 5+ years — versus the prior rules' all-or-nothing 100% at 5 years.³

For §1045 rollovers, the rule is: the exclusion schedule that applies to the replacement stock's final sale is determined by the original acquisition date of the original QSBS — not the date you invested in the replacement company. If your original stock was issued before July 4, 2025, the old 5-year / 100% rules govern the eventual exclusion on the replacement stock, even if the replacement company issued its shares after that date.

However, the per-issuer cap ($15M post-OBBBA vs. $10M pre-OBBBA) and the gross-asset ceiling ($75M vs. $50M) for the replacement company are evaluated under the rules that applied to the replacement company's own issuance — so a replacement company that issued stock after July 4, 2025 benefits from the $75M threshold.

Partial rollovers

You don't have to roll the entire sale. §1045 allows partial rollovers: you can defer the gain on the portion of proceeds you reinvest in replacement QSBS and recognize the gain on the remainder.¹ If you sell $10M of Company A (with $9.5M gain) and invest only $5M in replacement QSBS, you defer $5M of gain and recognize the other $4.5M currently.

Partial rollovers are useful when you need some liquidity but want to preserve as much of the gain deferral as possible.

Serial rollovers

Nothing in §1045 limits the number of rollovers. You can roll from Company A into Company B, and if Company B forces an early exit, roll again from Company B into Company C — each time resetting the 60-day clock from the new sale. The holding periods tack across each roll, and the reduced basis carries through each step. Serial rollovers are a legitimate strategy for investors in high-velocity venture portfolios who want to preserve the path to a §1202 exclusion while continuing to redeploy capital.

Reporting a §1045 rollover

A §1045 rollover is an election — it doesn't happen automatically. You make it on your tax return for the year of sale by:

1. Reporting the sale on Form 8949 with the gain recognized set to zero (or the partial amount) and a notation that §1045 applies.
2. Filing Schedule D reflecting the adjusted amount.
3. Attaching a detailed statement to your return that includes: the dates and amounts of the original sale and the replacement purchase, descriptions of both companies, the adjusted bases of original and replacement stock, and the amount of gain deferred.

Late elections or elections on amended returns are generally disfavored. The mechanics should be set up with a CPA experienced in QSBS transactions before the sale closes.

When §1045 isn't the answer

Section 1045 requires an active reinvestment decision — you need a qualified company to invest in, and 60 days to close. It isn't the right tool in every situation:

• You don't have a replacement investment — if you don't have a concrete QSBS-eligible company to invest in, forcing a rollover into a bad investment to defer tax is poor strategy. Tax deferral on a position that loses value means paying the deferred tax without the offsetting gain.
• The gain is small relative to the complexity — a §1045 rollover on a $200K gain has high legal and accounting cost relative to the tax saved. The strategy is most compelling on seven-figure gains.
• Waiting is an option — if you have any flexibility to avoid a sale before 5 years, waiting is almost always simpler and more certain. The §1202 exclusion at 5 years is cleaner than a rollover chain.
• State tax exposure — California, New Jersey, and Pennsylvania don't conform to §1202, and their treatment of §1045 can differ. A rollover that defers federal tax may not defer state tax. Get a state-specific analysis.

Sources

1. IRC § 1045 — Rollover of gain from qualified small business stock to another qualified small business stock: 60-day window, eligible-holder rule, partial-rollover mechanics, basis reduction.
2. Carta — QSBS Rollovers: A Guide to the Section 1045 Rollover: replacement-stock requirements, holding-period tacking for the §1202 5-year test.
3. Forvis Mazars — Qualified Small Business Stock (QSBS) – Post OBBBA: OBBBA tiered exclusion schedule, $75M gross-asset threshold, interaction with §1045 rollovers and pre-OBBBA acquisition dates.
4. Plante Moran — Keep the good tax planning rolling: Section 1045 rollover of QSBS: reporting requirements (Form 8949, Schedule D, attached election statement), serial rollover mechanics.

§1045 defers gain; it does not independently create an exclusion. Exclusion requires the replacement stock to qualify under §1202 when ultimately sold. State conformity varies — California, New Jersey, and Pennsylvania do not follow §1202. Confirm rollover eligibility, timing, and reporting with qualified tax counsel before executing any transaction. Values and thresholds verified against 2026 rules; OBBBA effective July 4, 2025.