Section 1045 Rollover: How to Defer QSBS Gains and Keep the Clock Running

A Section 1045 rollover lets you sell QSBS held more than six months and defer the entire gain by reinvesting the proceeds in new QSBS within 60 days — and your original holding period carries over, keeping the 3/4/5-year exclusion clock running. It is the escape hatch for founders forced to sell before year five.

This post is part of my complete guide to QSBS and Section 1202.

Sarah Chen has a problem. She founded a SaaS company in Seattle three years ago, structured it as a C-corp from day one, and just received an acquisition offer she can't refuse — $8 million for her shares. Her stock qualifies as QSBS under Section 1202.

But she's only held it for three years. Under the OBBBA's tiered exclusion schedule, she can exclude 50% of her gain at three years, 75% at four, and 100% at five. If she sells now, she's leaving half her exclusion on the table — roughly $1.05 million in federal tax she wouldn't owe if she could just wait two more years.

She doesn't want to pass on the deal. But she doesn't want to write a million-dollar check to the IRS either.

This is exactly the problem Section 1045 was designed to solve.

What Is a Section 1045 Rollover?

Section 1045 allows a taxpayer who sells QSBS to defer the gain by reinvesting the proceeds in new qualifying QSBS within 60 days. The original gain isn't recognized — it's rolled into the replacement stock by reducing your basis.

Think of it as a 1031 exchange for startup stock. You're not paying the tax now. You're pushing it forward into your next investment, where you can continue building toward the full five-year exclusion.

The Five Requirements

To qualify for a 1045 rollover, you must meet all five of these:

1. You must have held the original QSBS for more than six months. This is the minimum holding period — no exceptions. Stock held for five months and 29 days doesn't qualify.

2. You must reinvest in replacement QSBS within 60 days of the sale. The clock starts on the date of sale. There are no extensions. If day 61 arrives and you haven't closed on replacement stock, the rollover is gone.

3. The replacement stock must itself qualify as QSBS. It must be stock in a domestic C corporation with gross assets under $75 million (post-OBBBA), acquired at original issuance, in a company that meets the active business requirement.

4. You must reinvest the entire sale proceeds, not just the gain, to defer the full gain. Gain is recognized to the extent the amount realized exceeds what you reinvest in replacement QSBS. So if you sell for $8 million, you must reinvest the full $8 million to defer the entire gain; reinvest only $7.5 million and the $500,000 difference is recognized now (a partial rollover).

5. The replacement stock must be acquired for "cost." You must pay cash or property for the replacement stock — stock received for services (like a stock grant) does not qualify.

Holding Period Tacking: The Key Benefit

Here's what makes 1045 useful after the OBBBA: for purposes of the rollover and your QSBS clock, your original holding period generally carries over to the replacement stock, so you don't start over from zero.

Sarah held her original QSBS for three years. If she rolls into new QSBS, her holding clock generally continues rather than resetting to zero, which keeps her on track toward the five-year mark. Exactly how the Section 1202 exclusion applies to the deferred gain when she eventually sells the replacement stock is fact-specific and worth confirming with counsel before relying on it.

Under the OBBBA's tiered schedule:

At three years she can exclude 50%; at four years, 75%; at five years, 100%.

If the replacement company succeeds and Sarah sells after two more years, she gets the full 100% exclusion on the deferred gain plus any new appreciation.

The Basis Adjustment

When you roll over, your basis in the replacement stock is reduced by the amount of deferred gain. This is how the IRS tracks what you owe.

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 replacement stock has a basis of $500,000, even though she paid $8 million for it. The $7.5 million in deferred gain is embedded in that low basis and will be recognized when she eventually sells — unless she qualifies for a Section 1202 exclusion at that point.

The Angel Investor Play

Section 1045 isn't just for founders. Angel investors use it to manage portfolio risk while preserving QSBS benefits.

David Park is a Seattle angel investor. He invested $100,000 in a startup two years ago. The company just received an acquisition offer valuing his shares at $600,000. He's only at two years — short of the three-year minimum for any OBBBA exclusion. But he's past the six-month minimum for a 1045 rollover.

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

For Washington residents, the 1045 rollover is especially valuable. Deferred gains are not included in federal AGI, which means they don't trigger Washington's 7% capital gains tax or the new 9.9% income tax. You're deferring state tax as well as federal.

The 60-Day Trap

The single biggest mistake I see with 1045 rollovers: missing the 60-day window. Founders close a sale, deposit the proceeds, start looking for their next investment — and suddenly it's day 55 and they haven't found qualifying replacement stock.

My advice: identify your replacement QSBS investment before you sell. Have the term sheet ready. Know that the company qualifies. Don't start the 60-day clock until you have a plan to stop it.

*For the complete Section 1045 playbook — including advanced strategies for serial entrepreneurs, portfolio construction for angel investors, step-by-step basis calculations, Washington State tax analysis, and detailed checklists — get the Section 1045 QSBS Rollover Guide.*

*Have questions about whether a 1045 rollover makes sense for your situation? Book a 20-minute intro call.*

---

For the complete Section 1045 playbook with advanced strategies, checklists, and worked scenarios, get the Section 1045 QSBS Rollover Guide.

Have questions? Book a 20-minute intro call.

Section 1045 in Plain English

Section 1045 solves a specific problem: you sold QSBS before the five-year mark and now face a taxable gain. Without Section 1045, that gain is taxable now — and you may lose much or all of the Section 1202 exclusion. With Section 1045, you can defer the gain by reinvesting the proceeds into new QSBS within 60 days.

Think of it as a way to defer the gain and keep your QSBS clock moving — but only if you move quickly and follow the rules precisely, and the eventual Section 1202 treatment of the deferred gain depends on your facts.

Planning Strategies for Founders Expecting Early Exits

If you're a founder or early investor expecting a potential exit before five years, consider these planning strategies:

Build Section 1045 reinvestment into your exit planning. If an acquisition is possible before year five, identify potential replacement QSBS investments now. These might include investments in other startups, co-founder equity stakes in new ventures, or even carefully structured equity investments in early-stage companies in your network.

Negotiate for earnouts or deferred payments. If the buyer is offering cash upfront, ask for an earnout structure (payment contingent on post-acquisition performance) or a seller note (deferred payment). This can extend the holding period and potentially allow you to reach five years without triggering an early exit.

Structure acquisitions as stock deals if possible. If the buyer will accept payment in the buyer's stock (instead of cash), the transaction might be structured as a tax-free reorganization under Section 368. The buyer's stock would carry a new holding period, but if it qualifies as QSBS, you'd start fresh toward the five-year requirement. This isn't always possible, but it's worth exploring.

Consider a secondary sale to a financial buyer instead of a primary exit. If you're under five years and don't want to lose QSBS benefits, selling a portion of your stake to a venture firm or other investor might be better than a full acquisition. The portion you sell can trigger a Section 1045 rollover into new QSBS, while your remaining stake in the original company continues to accrue holding period toward the five-year threshold.

Work with a tax advisor to track holding periods closely. Once you're approaching year four or five, you need to know exactly how much of your QSBS qualifies for the full exclusion. Different classes of stock, different grant dates, and different vesting schedules can all affect your holding period. A detailed stock ledger and clear record-keeping are essential.

Who Uses Section 1045 — and When

Section 1045 is most relevant in three situations:

• Early secondary sales: An angel investor sells their stake in a secondary transaction before the five-year mark. Instead of paying tax on the gain, they reinvest in another qualifying startup.
• Founder liquidity events: A founder takes partial liquidity in a tender offer or secondary sale before reaching five years of QSBS holding.
• Portfolio recycling: An angel investor or small fund systematically rolls gains from early exits into new qualifying investments, deferring tax indefinitely and compounding returns.

The strategy is especially powerful for active angel investors who are continuously deploying capital — each rollover defers tax and the new QSBS begins its own five-year clock toward a permanent Section 1202 exclusion.

The Section 1045 Process Step by Step

1. Confirm QSBS status: The stock you're selling must qualify as QSBS — issued by a domestic C-corp that met the gross-assets cap at issuance ($50M for stock issued on or before July 4, 2025; $75M after), held for more than six months (but less than five years).
2. Sell the stock: Complete the sale. The 60-day clock starts on the date of sale, not the date you receive proceeds.
3. Identify replacement QSBS: You must reinvest in stock of a different qualified small business. You cannot roll into the same company. The replacement company must independently meet all Section 1202 requirements at the time of your investment.
4. Reinvest within 60 days: The entire proceeds (not just the gain) must be reinvested. Partial rollovers result in partial gain recognition. The 60-day deadline is absolute — no extensions.
5. Elect Section 1045 on your return: Report the rollover on Schedule D of your tax return. The election is made on the return for the year of the sale.

Head-to-Head: Section 1045 vs. Section 1202

Here's how the two provisions compare side by side:

| Feature | Section 1202 (Exclusion) | Section 1045 (Rollover) |

|---|---|---|

| Purpose | Permanently exclude gain from income | Defer gain by rolling into new QSBS |

| Minimum holding period | 5 years | 6 months |

| Maximum benefit | Exclude the greater of $10M (or $15M for post-OBBBA stock) or 10x adjusted basis (basis at original issuance (at least the FMV of any property contributed, per §1202(i)(1))) | Unlimited deferral (no dollar cap) |

| Permanence | Permanent — gain disappears | Temporary — gain follows you into the new stock |

| Tax result at exit | Zero federal tax on excluded gain | Tax is deferred until you sell the replacement stock |

| Reinvestment required? | No | Yes — within 60 days, into new QSBS |

| Can they work together? | Yes | Yes |

That last row is the one most people miss. These two provisions are not either/or. They can be combined, and for many founders, the combination is the optimal strategy.

When to Use Section 1202 Alone

This is the simplest case. You've held your QSBS for at least five years. Your gain is within the exclusion ceiling. You sell, you exclude, you're done.

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.

This is what every founder should aim for. But life doesn't always cooperate with the five-year plan.

When to Use Section 1045 Alone

The acquirer shows up at month 18. Or year two. Or year three. You haven't hit the five-year mark and you can't get a full 1202 exclusion yet.

Here's where Section 1045 saves you. Say you sell your QSBS at month 18 for a $3 million gain. Within 60 days, you reinvest $3 million into new QSBS — maybe your next startup, maybe an investment in another qualified small business. You defer the entire $3 million gain. Your basis in the new stock is reduced by $3 million, and your 18-month holding period from the old stock tacks onto the new stock.

If you hold the replacement stock for another 3.5 years, you'll have a combined holding period of five years. At that point, Section 1202 kicks in for the replacement stock, and the gain you deferred can potentially be excluded permanently when you sell.

Section 1045 alone is the right move when you have no 1202 exclusion available yet — you haven't hit five years — and you have a viable QSBS investment waiting for the rollover.

When to Use Both Together: The Power Move

This is where it gets interesting. Under current law (including the OBBBA tiered structure), if you've held QSBS for at least five years and the stock was acquired after September 27, 2010, you get a 100% exclusion. But if the holding period or acquisition date puts you into a tiered exclusion — 50% or 75% — you may have gain left over after the partial exclusion. That leftover gain is a candidate for a 1045 rollover.

Let me walk through an example. Suppose you acquired QSBS subject to the 50% exclusion tier. You sell after three years with a $4 million gain. Section 1202 excludes 50% — that's $2 million excluded permanently. You still have $2 million of recognized gain.

Now, if the stock also qualifies for a 1045 rollover (you've certainly held it for more than six months), you can take that remaining $2 million gain and roll it into new QSBS within 60 days. You've just eliminated your entire current federal tax bill: half through exclusion, half through deferral.

Or take a founder who sells at year four with a $6 million gain. Under a 75% exclusion tier, $4.5 million is excluded. The remaining $1.5 million? Roll it via 1045 into new QSBS. Federal tax today: zero. And if the replacement stock eventually qualifies for its own 1202 exclusion, that $1.5 million of deferred gain may ultimately be excluded as well.

The combination of 1202 and 1045 is the most powerful QSBS planning strategy available. It lets you extract the maximum exclusion and defer whatever is left.

The Serial Entrepreneur Playbook

If you're the kind of founder who builds, sells, and builds again, the 1045-to-1202 pipeline is your best friend.

Here's a concrete timeline. You start Company A in January 2024 and receive QSBS at founding. In July 2025 — 18 months later — an acquirer buys Company A, and you realize a $5 million gain. You can't use Section 1202 because you haven't held for five years. But you've held for more than six months, so Section 1045 is available.

Within 60 days, you invest the proceeds into QSBS in Company B — your next venture. You defer the entire $5 million gain. Your holding period from Company A (18 months) tacks onto your Company B stock.

You build Company B for another 3.5 years. By January 2029, your combined holding period is five years (18 months from Company A plus 3.5 years of Company B). When you sell Company B, Section 1202 applies. The $5 million of deferred gain from Company A, now embedded in your Company B stock, qualifies for the full 1202 exclusion — plus any additional gain from Company B's own appreciation.

That's the serial entrepreneur playbook: 1045 rolls the ball forward, and 1202 catches it at the finish line.

For founders thinking about how to multiply the exclusion even further — using trusts, gifts, and stacking strategies — I've written about that here.

Decision Flowchart

When a liquidity event hits, here's how to think about it:

Have you held the QSBS for more than five years? Use Section 1202. If you qualify for the 100% exclusion, you may not need anything else. If you're in a partial exclusion tier, consider combining 1202 with a 1045 rollover for the remaining gain.

Have you held for three to five years? Evaluate whether you qualify for a tiered exclusion under current law. If so, take the partial 1202 exclusion and roll the remainder via Section 1045 into new QSBS. The tacked holding period will help you reach the five-year mark faster on the replacement stock.

Have you held for six months to three years? Section 1202 isn't available yet, but Section 1045 is. Roll the entire gain into new QSBS within 60 days. Your holding period tacks, getting you closer to the 1202 finish line.

Have you held for less than six months? Neither provision applies. You'll need to recognize the gain. The lesson: don't sell QSBS in the first six months if you can possibly avoid it.

Section 1045 vs. 1031 Exchanges: Key Differences

If you're familiar with tax-deferred 1031 exchanges in real estate, you might wonder how Section 1045 compares. They're similar in concept but fundamentally different in structure.

A 1031 exchange allows you to sell real property and buy replacement real property of like kind, deferring the gain indefinitely. The replacement property must be identified within 45 days and closed within 180 days. There's no permanent tax benefit—you're just deferring—but the deferral is indefinite.

Section 1045 is more limited: the 60-day window is shorter, you must reinvest in a specific type of property (QSBS), and the deferral only makes sense if the replacement stock eventually qualifies for the Section 1202 exclusion. But unlike 1031 exchanges, Section 1045 offers the possibility of permanent tax exclusion (not just deferral) if the replacement stock qualifies for Section 1202 after five years.

In other words, 1031 is about deferral; Section 1045 is about deferral plus the potential for permanent exclusion.

The Basis Trap: What Most Guides Miss

When you do a Section 1045 rollover, the deferred gain reduces your basis in the replacement QSBS. This matters in two ways:

1. Lower basis = more gain to exclude under Section 1202. If you reinvest $500,000 of proceeds carrying a $400,000 deferred gain, your basis in the replacement stock is just $100,000 ($500,000 cost minus the $400,000 deferred gain) — far below what you put in. When you later sell for $1M and claim the Section 1202 exclusion, you're excluding more gain.
2. The 10x basis calculation changes. Section 1202's alternative cap is 10x your adjusted basis. A lower adjusted basis from a rollover can reduce this alternative cap — though for most early-stage investors, the $10M/$15M flat cap is the relevant limit anyway.

Model both scenarios carefully with a tax advisor before executing a rollover if your basis in the replacement stock will be significant.

---

Related: QSBS pillar

This post is for educational purposes only and is not legal or tax advice. Consult a qualified attorney about your specific situation.