Selling founders shares is one of the largest transactions you’ll ever sign, and the tax math behind it can take a third of the proceeds if you don’t plan ahead. This guide walks through how founders shares are taxed, when QSBS exclusion and Section 1045 rollovers help, and what to set aside for the IRS check that comes the following April.
More founders are taking their companies public while owning smaller stakes than in the past. In recent IPOs, founders held an average of just 7% equity, less than half of what tech founders typically owned a decade ago.
Why the drop? Companies are choosing to stay private longer instead of going public. Sometimes they want to do more private fundraising rounds so they can hit a higher valuation at IPO. Other times they use tender offers to sell shares to private parties before going public.
The lesson: whether you’re planning private fundraising, tender offers, or a future IPO, you need to plan for multiple selling events as a founder. Here’s how to do it.
What are founders shares?
Founders shares are the equity issued at the very beginning of a company, before any outside investors come in. The term isn’t an official IRS classification, so you don’t need to add it to your tax vocabulary. It’s just shorthand for the original equity grant.
For example, let’s say you were one of three people who founded a company, and each person put in $500 upfront. Each share only cost $0.0001, so each of you received 5 million shares. The company is “worth” $1,500 at incorporation, and each of you owns one-third (5,000,000 of the 15,000,000 total shares).
That tiny initial price becomes important later: it’s your cost basis. Every dollar above that, when you eventually sell, is a capital gain.
How are founders shares taxed when you sell?
When you sell founders shares, you owe both federal and state tax on the gain.
Most states, including California, treat the gain as ordinary income at your normal state rate. New York, New Jersey, and Massachusetts handle it the same way.
The federal government treats long-term capital gains differently from ordinary income. If you held the shares for more than a year before selling (which most founders have), federal tax on the gain is roughly 23.8%: 20% long-term capital gains plus 3.8% net investment income tax.
Worked example: in your Series C round, you sell 25% of your founders shares at $6.25 per share.
- Shares sold: 25% of 5,000,000 = 1,250,000
- Sale value: 1,250,000 × $6.25 = $7,812,500
- Federal tax at 23.8%: $1,859,256
That’s before state tax. In California, add another 13.3% on the gain at the top bracket, roughly $1,039,000 more. Total tax bill on a $7.8M payout: ~$2.9 million.
What is QSBS and the Section 1202 exclusion?
Section 1202 of the IRS tax code excludes QSBS (qualified small business stock) from federal long-term capital gains tax, up to the greater of $10 million or 10x your basis.
To qualify, your shares need to meet several conditions:
- You held them for at least five years before selling
- The company was a domestic C-corp at issuance and during the holding period
- The company had less than $50 million in gross assets when you got the shares
- The business is in a qualifying industry (most tech qualifies; financial services, hospitality, and farming generally don’t)
Using the example above, that $1,859,256 federal tax bill drops to $0 if your stock qualifies as QSBS and you held it for five-plus years. QSBS is the single biggest tax break available to founders, which is why timing your sale around the five-year mark matters so much.
Section 1045 rollover: when it makes sense
What if your shares don’t yet qualify for QSBS because you haven’t hit the five-year mark, and you really need to sell?
Section 1045 of the IRS tax code lets you roll the gain into a new QSBS investment, as long as you reinvest within 60 days. You sell your founders shares, take the proceeds, and put them into another small business that meets the QSBS guidelines. After the combined five-year holding period, you can sell the new shares without owing capital gains tax.
The good news: your money doesn’t need to sit in the new company for the full five years. The five-year clock counts the time you held shares in your original company plus the time in the new one.
So if your company was four years old when you sold 25% of your shares, you reinvest within 60 days, hold the new QSBS investment for one more year, and you qualify for the full five-year exclusion.
That said, a 1045 rollover isn’t always the smartest financial decision. Selling your shares before an IPO is a unique opportunity: the wealth you created is now real cash you can diversify into other assets. Tying that money up in another startup just for the tax benefit blocks you from doing that.
Rule of thumb: I wouldn’t do a Section 1045 rollover if this is your first liquidity event, or if your liquid net worth is less than $10 million. The diversification matters more than the tax savings.
Tender offers vs IPO: which selling event when?
Founders today rarely sell everything in a single transaction. Most do it in stages: a small slice in a tender offer, more during a secondary, and the rest at or after IPO.
Tender offers (private liquidity rounds) tend to be priced below the eventual IPO price but give you cash years earlier. The tax treatment is identical to selling in any other private transaction: gain is your sale price minus basis, and the QSBS five-year clock keeps running on whatever shares you don’t sell.
IPO selling has lockup considerations. Most founders are restricted from selling for 90 to 180 days after IPO, and large block sales after lockup can move the stock price. Spreading sales across multiple quarters smooths both market impact and your annual tax bracket.
The key principle: each selling event is independent for tax purposes, but the cumulative gain across the year is what determines your tax bracket. Selling $5 million in November and another $5 million in February spreads the income across two tax years and can save substantially on state tax in high-rate states.
State tax on founders shares (especially California)
California treats the entire gain as ordinary income at the state level, with a top rate of 13.3% (including the 1% mental health surcharge for income over $1 million).
For a $5 million long-term capital gain, that’s $665,000 in California state tax, on top of federal. Founders who can establish residency outside California before the sale (Texas, Florida, Washington, Nevada) save the entire state portion. The trick is timing and substance: California aggressively pursues residents who try to leave just before a liquidity event, and a “move” without genuinely changing where you live, work, and bank can be reversed in audit.
Other high-tax states (New York, New Jersey, Oregon, Hawaii) also tax capital gains as ordinary income, ranging from roughly 9% to 11%.
Common tax mistakes when selling founders shares
The same handful of errors show up after every founder liquidity event:
- Not tracking QSBS eligibility from day one. If you can’t prove the company met all Section 1202 conditions at issuance, the IRS won’t let you claim the exclusion later. Get an opinion letter from a tax attorney early.
- Missing the 60-day window for a Section 1045 rollover. The clock starts the day of sale, and there’s no extension. Plan the rollover before you sell, not after.
- Underpaying estimated taxes. A liquidity event can push you into a much higher bracket. To avoid an underpayment penalty, withholdings plus estimated payments should equal at least 110% of last year’s tax liability. If you sell mid-year, make a quarterly estimated payment immediately.
- Parking the tax reserve in a checking account. A million dollars sitting in a 0.01% account between sale and tax-due day costs you tens of thousands in opportunity cost. Park it in a high-yield savings account or short-term bond fund. (I like the DFA One-Year Fixed Income Fund for tax reserves.)
- Treating the windfall like a salary increase. Lifestyle inflation after a liquidity event eats more wealth than taxes do. The first ~30% of any sale should be earmarked for taxes, not spending.
If you’d rather think through year-end timing on equity sales before deciding when to pull the trigger, our guide on selling stock before year-end walks through the calendar tradeoffs.
Working with an advisor on founders share planning
The math on a single sale is straightforward. The math across multiple liquidity events, QSBS qualification, state residency, and estate planning is not. A founder selling $10 million across three transactions over four years has dozens of decisions that compound: which shares to sell first, when to start the QSBS clock on rollover, where to live the year of sale, what to do with the after-tax proceeds.
If you’re planning a tender offer, secondary sale, or IPO and want to maximize what you keep, get in touch using the button below to talk through your specific situation.
Common Questions
How are founders shares taxed when sold?
If founders shares qualify as QSBS under Section 1202 and are held at least 5 years, up to $15 million of gain (or 10x basis) can be excluded from federal taxes. Non-QSBS founders shares held more than a year are taxed at long-term capital gains rates. State taxes apply separately – California fully taxes QSBS gains.
What is QSBS treatment for founders shares?
QSBS is the Section 1202 exclusion that lets qualifying founders (and other early shareholders) exclude up to $15 million in capital gains from federal taxes. Requirements include direct issuance from the company, the company meeting the $75 million gross asset test at issuance, qualified-trade business, and 5+ year holding period.
How do you avoid a big tax bill on founders shares?
Strategies include qualifying for QSBS (5-year hold + asset test + qualified trade), gifting shares to spouse or non-grantor trusts to stack QSBS exclusions across multiple shareholders, donating appreciated shares to charity, harvesting offsetting losses, and timing sales across tax years to manage brackets. State residence planning can also have significant impact.
Can you sell some founders shares without losing QSBS treatment?
Yes. QSBS treatment applies per share, not per holding. You can sell a portion that has met the 5-year hold and qualify those for the exclusion while continuing to hold the rest. However, the company-level QSBS qualification is determined at issuance, not at sale, so subsequent company growth does not disqualify your previously-issued shares.
About the Author
Landon Loveall, CFP® is a Lead Advisor at KB Financial Advisors. He joined the firm in 2012 and leads the On Your Way to Wealth program for tech founders, FAANG employees, and pre-liquidity startup employees. Landon focuses on equity compensation strategy across RSUs, ISOs, NSOs, ESPPs, 83(b) elections, AMT planning, QSBS qualification, and pre-IPO preparation. He earned his CFP® designation in 2009 and works with technology professionals nationwide from his base in Nashville, TN.
