QSBS for Founders: The Tax Decision You Make at Formation That’s Worth Millions Later

By John Adams | Palo Alto Bookkeeping

You incorporate a company. You spend five years building it. You sell it for $15 million.

If you structured correctly on day one, you pay zero federal tax on that $15 million. If you didn’t, you pay roughly $3.6 million.

The difference is Section 1202 of the Internal Revenue Code, Qualified Small Business Stock, or QSBS. And the decisions that determine which outcome you get are made early, often before you’ve hired an employee or shipped a product. This post covers what a new founder needs to know and, more importantly, what a new founder needs to do.

Note: I am a bookkeeper, not a tax attorney. This is not tax advice. It is an explanation of a tax provision that every Silicon Valley founder should understand before they issue their first shares.

What QSBS Is

QSBS is a federal tax exclusion. If you hold qualified stock for long enough and the company meets certain requirements, you can exclude up to 100% of your capital gains from federal taxation when you sell.

The rules changed significantly in 2025. Under the One Big Beautiful Bill Act (OBBBA), signed July 4, 2025, stock issued after that date now benefits from:

• A $15 million exclusion cap per taxpayer, per issuer, up from the previous $10 million.
• A $75 million gross asset threshold for the company, up from $50 million.
• Tiered holding periods: 50% exclusion at 3 years, 75% at 4 years, and 100% at 5 years.

For stock issued before July 4, 2025, the old rules apply: a $10 million cap, a $50 million asset threshold, and a rigid five-year holding period with zero exclusion before then.

The Five Requirements, Explained for Someone Starting a Company Tomorrow

1. You must be a C corporation

An LLC or S corporation cannot issue QSBS. If you form as an LLC, you can convert later, but the five-year holding clock starts on the date the C corporation issues the stock, not the date the LLC was formed. Every month you spend as an LLC is a month you are not building toward QSBS eligibility.

Many founders now incorporate as C corporations from day one specifically to start the QSBS clock. This is a conversation to have with your attorney before you file formation documents.

2. Gross assets must not exceed $75 million

The company’s aggregate gross assets, cash, property, and other assets measured at adjusted tax basis, must be $75 million or less at all times before and immediately after your stock is issued. For pre-July 2025 stock, the threshold is $50 million.

This is why the timing of stock issuance relative to fundraising matters. If you raise a large round that pushes gross assets above the threshold, stock issued after that round will not qualify. Stock issued before the round still qualifies if the threshold was not exceeded at that earlier date. Founders who issue their shares early, before significant capital comes in, lock in QSBS eligibility. Founders who wait may lock themselves out.

3. At least 80% of assets must be used in an active business

This rule prevents holding companies and passive investment vehicles from claiming QSBS. The company must be doing something real.

Certain industries are explicitly excluded. The one that trips up Silicon Valley founders most often is professional services. If your company provides accounting, legal, consulting, financial services, health services, engineering, or architecture services, you are likely disqualified. A SaaS company that sells software to accountants qualifies. A company that provides accounting services directly to clients does not.

A related nuance for life sciences founders is that the IRS excludes “health services” but does not exclude biotech or pharmaceutical companies that develop proprietary products, such as drugs, devices, and diagnostics. Product companies qualify. Service providers do not. Founders in this space should confirm the distinction with counsel early.

Other excluded industries include banking, insurance, investing, farming, hospitality, and natural resource extraction.

4. You must acquire the stock directly from the company

Stock must be acquired at original issuance, meaning directly from the corporation, in exchange for money, property, or services. This covers founder shares, exercised stock options (both ISOs and NSOs), and restricted stock. It does not cover shares purchased from another shareholder on the secondary market.

There are limited exceptions for gifts, inheritance, and certain partnership distributions. But the general rule is simple: if you bought the shares from someone who is not the company, those shares are not QSBS.

5. You must hold the stock for at least five years

For stock issued before July 4, 2025, the holding period is a hard five years. Sell at 4 years and 11 months, and the exclusion is zero. For stock issued after July 4, 2025, the tiered system applies: 50% exclusion at 3 years, 75% at 4 years, and 100% at 5 years. This gives founders some flexibility to take liquidity earlier without forfeiting the entire benefit.

The five-year clock starts when you acquire the shares, not when the company is formed, and not when you start working on the idea. The date on your stock purchase agreement or option exercise matters. If you are receiving restricted stock subject to vesting, the clock starts when you file your 83(b) election, which is covered more below.

The California Problem

QSBS is a federal exclusion. The state where you live gets to decide whether to respect it.

California does not.

If you sell QSBS while living in California, the state will tax your gain at up to 13.3%, the highest state capital gains rate in the country. On a $15 million gain that is fully excluded from federal tax, California will still take roughly $2 million.

Founders who anticipate a large exit sometimes consider relocating to a conforming state before the sale. This is not a casual decision, and it requires genuine, documented relocation before the liquidity event, not a mail-forwarding address set up the month before. States that see large exit activity audit residency claims aggressively. Talk to a tax attorney well before any planned move.

States that currently conform to federal QSBS treatment include Texas, Florida, Washington, Nevada, New York, New Jersey (as of 2026), Colorado, and most others. States other than California that do not conform include Alabama, Mississippi, Pennsylvania, Oregon, and Washington D.C. The landscape shifts with state legislative sessions, New Jersey only recently adopted conformity and Oregon recently decoupled retroactively, so verify before relying on any state’s current status.

What the Numbers Actually Look Like

Assume you found a company in 2025, structure it as a C corporation, issue yourself stock when gross assets are under $75 million, and sell after six years for a $15 million gain.

Metric	Federal Tax	California Tax
Gain	$15,000,000	$15,000,000
QSBS Exclusion	$15,000,000	$0 (CA does not conform)
Taxable Amount	$0	$15,000,000
Tax Rate	20% (not applied)	13.3%
Tax Owed	$0	~$1,995,000

You save roughly $3 million in federal tax. California still takes its share.

If you had structured as an LLC, issued membership interests instead of C corporation stock, or exceeded the asset threshold before issuing your shares, the federal tax bill on that same gain would be approximately $3.57 million, including the 3.8% net investment income tax, instead of zero.

A note on the unexcluded portion: the part of a QSBS gain that is not excluded, whether because you exceeded the cap or sold before the holding period, is taxed at a flat 28% federal rate, not the standard 20% long-term capital gains rate. Add the 3.8% NIIT and the combined rate is 31.8%. This makes holding the full five years more valuable than founders sometimes assume.

Decisions You Need to Make Now (Not Later)

Entity choice

If you have not yet formed your company, the decision between LLC and C corporation has QSBS implications that compound over time. An LLC may be simpler administratively. It also permanently forecloses QSBS until you convert, and even after conversion, the clock resets at the date of C corp stock issuance. Founders who intend to take venture capital and pursue a traditional exit should strongly consider incorporating as a C corporation from day one.

This is not universally correct. Some businesses should be LLCs. But it is a conversation to have explicitly, with QSBS on the agenda, not a default to the simplest filing.

Stock issuance timing

Issue your founder shares before you raise significant capital. The gross asset test applies at the moment of issuance. If you incorporate, fund the company with $5,000 of your own money, and issue yourself shares immediately, your gross assets at issuance are negligible. If you wait until after a $4 million seed round closes, assets at issuance include that cash, and you are closer to the limit.

File your 83(b) election within 30 days

If you receive restricted stock subject to vesting, filing an 83(b) election with the IRS within 30 days of issuance starts your entire holding period immediately. If you do not file, the clock restarts with each vesting tranche, meaning at a year-four exit, some of your shares have a four-year holding period and some have less than a year. The difference can disqualify a portion of your gain from QSBS treatment entirely.

This is a one-page form. Miss the 30-day window and the election is gone forever. Make this part of your incorporation checklist.

Know the mixed cap table problem

Stock issued before July 4, 2025 operates under the old rules. Stock issued after operates under the new OBBBA rules. If you issued shares on both sides of that date, say, founder shares in early 2025 and additional shares from an option exercise in late 2025, you hold two blocks of stock with different exclusion caps, different asset thresholds, and different holding period rules. At exit, which shares you sell and which regime applies will matter. Track it.

Document everything at issuance

If you ever claim QSBS treatment, the burden of proof is on you, not the IRS, not your company, not your CPA. You will need records of:

• The company’s gross assets at the date your shares were issued (a balance sheet, even an informal one).
• The corporate structure at issuance (articles of incorporation showing C corporation status).
• The nature of the business at issuance (evidence of active business activity, not passive holding).
• The date you acquired the shares and what you paid or contributed for them.
• Board resolutions authorizing the stock issuance.

Ask your attorney for a QSBS attestation letter at the time of issuance. This is a formal document from the company confirming that the shares met QSBS requirements, gross assets, active business, corporate structure, and redemption history. Buyers, auditors, and the IRS expect to see these. Reconstructing one seven years later from memory is expensive and sometimes impossible.

Start gifting early, if you plan to stack

The $15 million exclusion cap applies per taxpayer, per issuer. If you anticipate a gain larger than $15 million, gifting shares to family members or non-grantor trusts creates additional taxpayers, each with their own $15 million exclusion. A founder with a $45 million gain who gifts shares to a spouse and one child could potentially exclude the entire amount from federal taxation.

The strategy: gift QSBS when the shares are worth very little. At a $3 million seed round, shares are fractions of a penny. The gift tax cost is negligible. The recipient gets the eventual gain and their own exclusion bucket.

Gift years before any sale, not weeks. If you gift stock on Monday and the company announces an acquisition on Tuesday, the IRS can recharacterize the gift-then-sale as an assignment of income, meaning you pay tax as if you sold the shares yourself. There is no bright-line rule for how far in advance gifts must be made, but the principle is clear: the further removed the gift is from any sale discussions, the safer it is. Gifts made years before an exit are virtually bulletproof. Gifts made after a letter of intent is signed are virtually indefensible.

If you are married and in California, a community property state, do not assume community property automatically gives both spouses separate exclusions. The law is unsettled. The safest approach is to hold QSBS as separate property, or ensure both spouses are on the cap table independently from the start. Structure it deliberately with the advice of counsel.

If you use trusts, be aware of the IRS’s authority under Section 643(f) to collapse multiple trusts for the same beneficiary into a single taxpayer if the primary purpose is tax avoidance. Trust stacking works, but it must be grounded in genuine estate planning, not manufactured solely for the exclusion.

Beyond the Basics: Section 1045 Rollovers

If you sell QSBS after holding it for more than six months, you can defer the gain by reinvesting the proceeds in other QSBS within 60 days under Section 1045. The holding period from the original stock carries over to the replacement stock.

This matters in two scenarios. First, for serial founders who want to roll gains from one company into the next without triggering tax. Second, for founders forced into an early exit, an acquisition before the five-year holding period is complete. The rollover preserves the clock and defers the tax until the replacement stock is sold. It does not eliminate the holding period requirement, it just gives you more time to meet it on a new investment.

Common Mistakes That Are Hard to Fix Later

• Forming as an LLC and delaying conversion. Every month as an LLC is a month the QSBS clock is not running. Convert early or form as a C corp.
• Issuing founder shares after a funding round. You control the timing. Issue early.
• Failing to file an 83(b) election. A one-page form due within 30 days of issuance. Miss the window and your holding period is fractured across vesting dates.
• Operating in a disqualified industry without realizing it. The professional services exclusion is broad. The health services exclusion does not apply to biotech product companies but does apply to medical service providers. Confirm with counsel.
• Failing to document anything at issuance. The IRS does not take your word for it. Keep records and get an attestation letter.
• Assuming California respects the federal exclusion. It does not. Plan for state tax separately.
• Selling at 4 years and 11 months under the old rules. The five-year holding period is absolute for pre-July 2025 stock. A sale even one day early forfeits the entire exclusion.
• Gifting QSBS too close to an exit. The assignment of income doctrine can unwind the entire strategy. Time your gifts well ahead of any sale.
• Mixing pre- and post-July 2025 stock without tracking the differences. Different rules apply to different blocks. Know which shares are which.

Who to Talk To

QSBS requires coordination between your corporate attorney, your CPA, and potentially an estate planning attorney if you are pursuing a gifting strategy. The bookkeeper’s role is narrower: maintain the records that support a QSBS claim, track holding periods, and flag asset thresholds as the company approaches them. But the strategic decisions belong to the founder with the advice of counsel.

If you are forming a company in the Bay Area and want an introduction to a CPA or attorney who understands QSBS, I can point you toward a few. The questions to ask them are:

1. Should I form as a C corporation or LLC, given my exit ambitions?
2. When should I issue my founder shares?
3. Do I need to file an 83(b) election?
4. What documentation do I need to maintain from day one?
5. Does my business model fall into a disqualified industry?
6. If I plan to exit in California, what is my state tax exposure?
7. Should I begin gifting shares now for stacking purposes?

The time to ask these questions is before you file formation documents. After that, some doors are already closed.

Palo Alto Bookkeeping is a solo practice by John Adams, specializing in QuickBooks Online cleanup, ecommerce bookkeeping, and ongoing monthly bookkeeping for Silicon Valley small businesses. This post provides general information and does not constitute tax or legal advice. Consult a qualified tax professional or attorney regarding your specific situation.