You just got an acquisition offer on your startup. It's a good number — life-changing, even. Your tax advisor listens to the details and then says two things: "1045" and "1202." Both involve qualified small business stock. Both can save you millions in federal taxes. But they do very different things, and which one you need — or whether you need both — depends entirely on your timeline and your situation.
I've spent over 25 years advising founders on exactly this question, and I still see smart people confuse the two or, worse, miss one entirely. So let's break it down. (For a deeper dive on the QSBS landscape, see my complete guide to QSBS and Section 1202.)
Section 1202 in 30 Seconds
Section 1202 is the gain exclusion. If you hold qualified small business stock for at least five years, you can exclude up to the greater of $15 million or ten times your adjusted basis in the stock from federal capital gains tax when you sell. For stock acquired after September 27, 2010, that exclusion is 100% of the gain. The gain simply disappears for federal income tax purposes.
This is the provision you plan for from day one. You incorporate as a C corporation, you issue stock at formation, you make sure the company meets the QSBS requirements — active business, domestic C corp, aggregate gross assets under $75 million at the time of issuance — and then you hold. If everything works and you hold for five years, you pay zero federal tax on your exit gain up to the exclusion ceiling.
Section 1202 is the destination.
Section 1045 in 30 Seconds
Section 1045 is the rollover. If you've held QSBS for at least six months, you can sell it, reinvest the proceeds in new QSBS within 60 days, and defer the gain. You don't exclude it — you defer it. Your basis in the new stock is reduced by the gain you rolled over, and your holding period from the old stock tacks onto the new stock.
The goal of Section 1045 is to get you through a liquidity event when the timing isn't right for a full 1202 exclusion. The acquirer shows up at year two, not year five. You can't wait. Section 1045 lets you take the deal, roll the gain forward, and keep building toward that 1202 exclusion with your next company.
Section 1045 is the bridge. (I've written a detailed guide to Section 1045 rollovers here, and for those who want the full playbook, I have a comprehensive 1045 guide on Gumroad.)
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 10x basis | 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 five 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.
The Washington State Angle
For founders in Washington State, both strategies carry an additional benefit. Gains excluded under Section 1202 are excluded from federal adjusted gross income. That matters because Washington's capital gains tax — and the new income tax — key off of federal taxable income and AGI. Gain that never shows up in your federal AGI generally won't trigger Washington State tax either.
The same logic applies to Section 1045 rollovers. When you defer gain under 1045, you don't recognize it for federal purposes, which means it doesn't flow through to your Washington State return in the year of the rollover.
The result: both 1202 and 1045 can help you avoid not just federal tax, but Washington State tax as well. For a deeper dive on Washington State tax planning for founders, including how QSBS interacts with the state-level taxes, I've put together a comprehensive WA tax planning guide.
The Bottom Line
Section 1202 is the destination — the permanent exclusion that makes your startup exit tax-free at the federal level. Section 1045 is the bridge — the rollover that keeps you in the game when a sale happens before the five-year clock runs out.
The best founders plan for Section 1202 from the day they incorporate. They set up the C corp, they issue stock properly, they monitor the gross asset test, and they hold for five years. But they also know that Section 1045 is there if the timeline doesn't cooperate — if the acquirer comes knocking early, if the company pivots, if life happens.
And the most sophisticated founders use both together: taking whatever exclusion is available under 1202 and rolling the rest via 1045 into their next venture, building a chain of QSBS that compounds tax savings across multiple companies and multiple exits.
If you're a founder and you haven't thought about both of these provisions, now is the time. Talk to your tax advisor. Make sure your stock qualifies. And know your options before the acquisition offer lands.
This post is for informational purposes only and does not constitute tax or legal advice. QSBS qualification depends on numerous factors specific to your situation. Consult a qualified tax professional before making any decisions.
