What Is QSBS? Rules, Tax Benefits, and California Considerations

What Is QSBS?

Qualified Small Business Stock, commonly called QSBS, is stock in a qualifying U.S. C corporation that may be eligible for a major federal tax benefit under Internal Revenue Code Section 1202.

For founders, early employees, angel investors, and startup investors, QSBS can be one of the most valuable tax planning opportunities available. If the stock qualifies and the holding-period rules are met, a shareholder may be able to exclude a significant amount of gain from federal capital gains tax when the stock is sold.

For California founders and startup employees, however, there is an important catch: California does not conform to the federal QSBS exclusion. That means a gain may be excluded for federal tax purposes but still be taxable by California.

This article explains what QSBS is, who qualifies, how the Section 1202 rules work, what changed under the 2025 QSBS rules, and what California residents should understand before relying on the QSBS tax exclusion.

Why QSBS Matters for Founders and Startup Employees

Startup equity can create significant wealth, but it can also create significant taxes. For founders and early employees who receive shares when a company is worth very little, most of the eventual exit value may be capital gain.

QSBS can materially change the after-tax outcome.

For example, assume a founder receives shares at company formation and later sells those shares for a $15 million gain. If the shares qualify for the full QSBS exclusion under the post-July 4, 2025 rules, the founder may owe no federal capital gains tax on that qualifying gain, assuming all Section 1202 requirements are satisfied and the gain is within the applicable cap.

Without QSBS, the same gain could be subject to federal long-term capital gains tax, the 3.8% Net Investment Income Tax, and state income tax.

For California residents, the federal benefit can still be powerful, but it does not make the exit tax-free. California generally taxes capital gains as ordinary income and does not provide a state-level QSBS exclusion.

What Changed Under the 2025 QSBS Rules?

Federal tax legislation enacted in 2025 expanded Section 1202 for stock acquired after July 4, 2025. The changes apply prospectively, which means stock acquired before or on July 4, 2025 generally remains subject to the prior QSBS rules.

1. New Partial QSBS Exclusions Before Five Years

Under the prior rules, shareholders generally needed to hold QSBS for more than five years to receive the federal exclusion.

For qualifying stock acquired after July 4, 2025, the rules now provide a tiered exclusion schedule:

This change may benefit founders, employees, and investors whose companies exit before the traditional five-year mark.

The portion of QSBS gain that is not excluded may be taxed federally at a rate of up to 28%, plus the 3.8% Net Investment Income Tax where applicable. This is why a partial QSBS exclusion can still leave a meaningful federal tax bill.

2. QSBS Exclusion Cap Increased to $15 Million

For stock acquired after July 4, 2025, the dollar-based QSBS exclusion cap increased from $10 million to $15 million. The $15 million cap is indexed for inflation beginning in 2027. The alternative cap of 10 times the shareholder's adjusted basis remains available.

For post-July 4, 2025 QSBS, the exclusion cap is generally the greater of:

• $15 million, reduced by prior eligible QSBS gain from the same issuer, or
• 10 times the shareholder's adjusted basis in the QSBS sold.

For founders with very low basis, the dollar cap often matters most. For investors who purchased preferred stock for a meaningful amount, the 10-times-basis rule can provide a larger exclusion.

3. Gross-Assets Threshold Increased to $75 Million

To issue QSBS, the company must be a qualified small business at the time the stock is issued. For stock acquired after July 4, 2025, the company's aggregate gross-assets threshold increased from $50 million to $75 million, with inflation adjustments beginning in 2027.

This change may allow some later-stage startups to issue QSBS-eligible stock that would not have qualified under the prior $50 million threshold.

Old QSBS Rules vs. New QSBS Rules

Who Qualifies for QSBS?

QSBS eligibility depends on both the company and the shareholder. A founder or employee can lose QSBS treatment if either side fails to meet the rules.

Company Requirements for QSBS

1. The Company Must Be a Domestic C Corporation

Only stock in a domestic C corporation can qualify as QSBS. S corporations, partnerships, and LLCs taxed as partnerships cannot issue QSBS.

If an LLC later converts into a C corporation, the QSBS analysis may begin when C corporation stock is issued. Pre-conversion appreciation generally does not become QSBS gain.

2. The Company Must Meet the Gross-Assets Test

At the time the stock is issued, the company's aggregate gross assets must not exceed the applicable threshold.

For stock acquired after July 4, 2025, the threshold is $75 million. For stock acquired before or on July 4, 2025, the prior $50 million threshold generally applies.

The test is measured before and immediately after the stock issuance, including the money or property the corporation receives in the issuance.

3. The Company Must Be an Active Qualified Business

During substantially all of the shareholder's holding period, at least 80% of the corporation's assets must be used in the active conduct of one or more qualified trades or businesses. Section 1202 includes detailed rules on what counts as a qualified business and which businesses are excluded.

This requirement can become important when a startup raises a large financing round and holds significant cash, intellectual property, investments, or non-operating assets.

4. Certain Businesses Do Not Qualify for QSBS

Not every startup can issue QSBS. Section 1202 excludes several types of businesses, including many service businesses and financial businesses.

Excluded fields include:

• health
• law
• accounting
• actuarial science
• consulting
• athletics
• performing arts
• financial services
• brokerage services
• banking
• insurance
• financing
• leasing
• investing
• farming
• mining
• hotels
• restaurants
• businesses where the principal asset is the reputation or skill of one or more employees

Many software, hardware, biotech, manufacturing, and product-based companies may qualify. Fintech companies require extra analysis because financial services, brokerage, banking, financing, investing, and similar businesses may be excluded under Section 1202.

5. Stock Redemptions Can Affect QSBS Eligibility

Certain company stock repurchases can create QSBS problems. This includes some redemptions from the shareholder or related persons around the time of issuance, as well as significant company-wide redemptions within specified periods.

This issue often arises when companies repurchase founder shares, clean up cap tables, conduct tender offers, or facilitate secondary transactions. Redemptions should be reviewed before assuming stock qualifies as QSBS.

Shareholder Requirements for QSBS

1. The Shareholder Must Be a Non-Corporate Taxpayer

The QSBS exclusion is generally available to non-corporate taxpayers, including individuals, certain trusts, partnerships, LLCs taxed as partnerships, and S corporations.

C corporations cannot claim the Section 1202 exclusion.

2. The Stock Must Be Acquired at Original Issuance

The shareholder generally must acquire the stock directly from the company in exchange for money, property, or services.

Common examples include:

• founder common stock issued at formation
• restricted stock issued for services
• shares acquired through exercise of stock options
• preferred stock purchased directly from the company
• stock issued when certain instruments convert into equity

Buying shares from another shareholder in a secondary transaction generally does not satisfy the original-issuance requirement. Limited exceptions may apply for certain gifts, transfers at death, and partnership distributions.

3. The Shareholder Must Meet the Holding Period

For stock acquired before or on July 4, 2025, the shareholder generally must hold the stock for more than five years to receive the full federal QSBS exclusion.

For stock acquired after July 4, 2025, the shareholder may qualify for a 50% exclusion after at least three years, a 75% exclusion after at least four years, and a 100% exclusion after at least five years.

How Much Gain Can QSBS Exclude?

The QSBS exclusion limit is generally applied per taxpayer, per issuer. For post-July 4, 2025 stock, the exclusion cap is generally the greater of:

• $15 million, reduced by prior eligible gain excluded from the same issuer, or
• 10 times the shareholder's adjusted basis in QSBS of that issuer sold during the year.

For older QSBS, the dollar cap is generally $10 million rather than $15 million.

Example: Founder With Low-Basis QSBS

A founder receives shares at formation for a nominal amount. Years later, the founder sells qualifying post-July 4, 2025 QSBS for a $15 million gain after satisfying the full holding period.

If all requirements are met, the founder may be able to exclude the full $15 million gain from federal capital gains tax.

Example: Investor With High-Basis QSBS

An investor purchases $4 million of preferred stock directly from a qualifying C corporation. If the stock later qualifies as QSBS and is sold after the required holding period, the investor's exclusion cap could be as high as $40 million under the 10-times-basis rule.

California QSBS Rules: Why California Founders Need Special Planning

California does not conform to the federal QSBS exclusion. As a result, California residents generally pay California income tax on the full gain, even if the gain is excluded for federal purposes.

This is one of the most common misunderstandings among California founders and startup employees. QSBS can reduce or eliminate federal capital gains tax, but it does not eliminate California tax for California residents.

California taxes capital gains as ordinary income. For high-income California taxpayers, the top marginal state income tax rate can reach 13.3%. California's nonconformity makes state-tax planning especially important for large startup exits.

Some founders consider moving to a no-income-tax state before a liquidity event. A residency change can be effective only if it is genuine, well-documented, and completed before the taxable sale. California's Franchise Tax Board closely scrutinizes residency changes, especially when a major liquidity event occurs shortly after a move.

Residency planning should be addressed well in advance with qualified tax counsel.

QSBS Stacking: Can You Multiply the Exclusion?

Because the QSBS cap is generally applied per taxpayer, founders and investors sometimes use gifting strategies to expand the total federal exclusion available across a family or estate plan.

This is often called QSBS stacking.

Common strategies may include gifts to:

• a spouse
• adult children
• non-grantor trusts
• other family members or beneficiaries

A properly structured gift of QSBS may allow the recipient to tack onto the donor's holding period and claim their own QSBS exclusion. This can potentially multiply the available federal exclusion across multiple taxpayers.

For example, a founder with highly appreciated QSBS may gift shares to separate non-grantor trusts for family beneficiaries before a liquidity event. If properly structured, each trust may be treated as a separate taxpayer with its own QSBS exclusion cap.

This strategy is complex. It can involve income tax, gift tax, estate tax, trust law, state residency, and anti-abuse considerations. It should be implemented before any binding sale commitment. Transfers made too close to a signed transaction may be challenged.

Section 1045 Rollovers: What If You Sell QSBS Before the Holding Period?

Section 1045 may allow a shareholder to defer gain on the sale of QSBS if the shareholder held the original QSBS for more than six months and reinvests the proceeds into replacement QSBS within 60 days.

This can be useful when a startup is acquired before the shareholder satisfies the full QSBS holding period.

If the rollover is properly completed, the shareholder may be able to defer the gain and continue building toward QSBS eligibility through the replacement stock. The holding period for the original QSBS may carry over to the replacement QSBS.

This strategy is highly time-sensitive. The 60-day reinvestment window is short, and the replacement stock must also qualify.

QSBS Planning for Stock Options, 83(b) Elections, SAFEs, and Convertible Notes

Stock Options

Stock options are not QSBS while they are merely options. The QSBS holding period generally begins when the option is exercised and actual stock is issued.

This is important for startup employees. Receiving an option grant usually does not start the QSBS clock. Exercising the option may be required to begin the holding period.

Restricted Stock and 83(b) Elections

Restricted stock can be more favorable if handled correctly.

When a founder or early employee receives restricted stock, filing a timely Section 83(b) election may start the QSBS holding period at the grant date rather than waiting until vesting. The election must generally be filed within 30 days of the stock grant.

Missing the 83(b) deadline can materially affect both tax timing and QSBS planning.

SAFEs and Convertible Notes

SAFEs and convertible notes require careful analysis.

In many cases, the QSBS holding period begins when the SAFE or note converts into stock, not when the SAFE or note was signed. Investors should not assume that the QSBS clock started on the date they funded a SAFE or convertible note.

The treatment can depend on the instrument and the transaction structure, so investors should retain conversion documents and confirm timing with a qualified tax advisor.

QSBS Documentation Checklist

QSBS is often claimed many years after shares are issued. By the time there is an acquisition, IPO, or secondary sale, it may be difficult to reconstruct the facts needed to support the exclusion.

Founders, employees, and investors should retain:

• stock purchase agreements
• restricted stock agreements
• option grant and exercise records
• proof of timely 83(b) elections
• board consents approving stock issuances
• capitalization tables at issuance
• company balance sheets before and after issuance
• records showing the company was a domestic C corporation
• documentation supporting the active business requirement
• SAFE and convertible note documents
• conversion documents
• records of stock repurchases or redemptions
• trust and gift documentation, if shares were transferred

For founders, it can be valuable to prepare a QSBS memo while the facts are fresh rather than waiting until a sale.

Common QSBS Mistakes

Mistake 1: Assuming All Startup Stock Is QSBS

Not all startup stock qualifies. The company must be a domestic C corporation, satisfy the gross-assets test, operate an eligible active business, and avoid disqualifying redemptions.

Mistake 2: Waiting Too Long to Exercise Options

For employees, the QSBS clock generally starts when shares are issued, not when options are granted. Waiting to exercise can delay or prevent QSBS eligibility.

Mistake 3: Assuming California Follows Federal QSBS Rules

California does not conform to Section 1202. A federal QSBS exclusion does not automatically reduce California tax.

Mistake 4: Ignoring Redemptions and Secondary Sales

Stock repurchases, tender offers, and secondary transactions can create QSBS issues. These should be reviewed carefully before a sale.

Mistake 5: Planning After a Deal Is Already Signed

QSBS stacking, gifting, trust planning, and residency planning generally need to happen before there is a binding sale commitment. Last-minute planning may not work.

Final Thoughts

QSBS can be a powerful federal tax benefit for founders, early employees, and startup investors. The 2025 QSBS changes made Section 1202 more generous for newly issued stock by increasing the exclusion cap, raising the gross-assets threshold, and allowing partial exclusions before five years.

But QSBS is not automatic. Small details can determine whether millions of dollars of gain qualify for federal exclusion. The timing of stock issuance, option exercise, company financing, business activity, redemptions, SAFEs, convertible notes, trust transfers, and residency can all matter.

For California founders, the planning challenge is even greater. QSBS may reduce or eliminate federal tax, but California generally taxes the full gain. That makes early planning around entity structure, stock documentation, option exercise, 83(b) elections, trust planning, Section 1045 rollovers, and residency especially important.

The best time to review QSBS eligibility is before a liquidity event, not after one. Founders, employees, and investors should evaluate QSBS when shares are issued, when options are exercised, when financing rounds close, and before any major secondary sale, acquisition, or IPO.