Qualified small business stock is one of the most valuable provisions in the tax code for people who take equity in early-stage companies, and one of the most frequently discovered too late. It allows the exclusion of a substantial portion of the gain when qualifying shares are sold — and eligibility depends on facts established years earlier, at the moment the stock was issued.
By the time an exit is imminent, you cannot change whether the company qualified. You can only find out.
This is general information, not tax advice. Rules are detailed and fact-specific; work with a qualified professional.
What changed in 2026
- Holding period became tiered. Legislation in 2025 replaced the all-or-nothing five-year cliff with graduated exclusion at earlier holding periods, for stock acquired after the effective date.
- Thresholds rose. Both the company's gross asset limit at issuance and the per-taxpayer exclusion cap were increased, widening the range of companies and outcomes covered.
- Two regimes now coexist. Stock acquired before the change follows the prior rules; stock after follows the new ones, which means the acquisition date determines which analysis applies.
- Attention increased. The expansion drew more founders and employees into the analysis, and more advisers began raising it at issuance rather than at exit.
What has to be true
| Requirement |
Applies to |
Note |
| Domestic C corporation |
The company |
S corporations and LLCs do not qualify |
| Gross assets below the threshold at issuance |
The company |
Measured at and immediately after issuance |
| Active qualified trade or business |
The company |
Several service industries are excluded |
| Original issuance |
Your shares |
Bought from the company, not from another shareholder |
| Holding period met |
Your shares |
Tiered under the new rules |
| No disqualifying redemptions |
The company |
Buybacks near issuance can taint shares |
The original issuance requirement catches people regularly. Buying shares on a secondary market from a departing employee generally does not qualify, because the stock was not issued to you by the company. Exercising an option granted to you does qualify, since exercise is an issuance.
The excluded-industry list is broader than expected and includes several professional services categories. A company that looks like a startup may be in an excluded line of business, and this is determined by what the company actually does rather than how it describes itself.
The traps
Redemptions. If the company repurchased stock from anyone within defined windows around your issuance date, your shares can be disqualified — even though you had nothing to do with the buyback and may not know it happened. Ask.
Conversion timing. A company that started as an LLC and converted to a C corporation starts the clock at conversion, and the asset test applies then. Early participants sometimes assume their holding period runs from the original entity.
Losing the paperwork. Establishing eligibility years later requires evidence about the company's assets and business at issuance. Get a written QSBS attestation from the company while it is still around and cooperative. After an acquisition, obtaining it becomes much harder.
Assuming it is automatic. The exclusion is claimed on your return with supporting documentation. Nobody applies it for you.
For the general treatment of investment gains outside this provision, capital gains tax explained covers the default rules that apply when shares do not qualify.
Common mistakes
- Not asking at issuance. The facts that determine eligibility exist then; verify then.
- Assuming secondary purchases qualify. Original issuance is a hard requirement.
- Ignoring state treatment. Some states do not conform to the federal exclusion, so a federal win may still carry a state bill.
- Forgetting the company-level tests. Your shares can be perfect and the company can still fail to qualify.
- Waiting until an exit is announced. Planning options narrow sharply once a transaction is underway.
FAQ
Does QSBS apply to stock options?
The holding period generally starts at exercise, not grant, since that is when stock is issued to you. This makes exercise timing consequential.
What if I sell before meeting the holding period?
Under the tiered rules for newer stock, partial exclusion may be available earlier. There are also rollover provisions allowing reinvestment into other qualifying stock in some circumstances.
Do all states follow the federal rules?
No. State conformity varies, and some states decline the exclusion entirely. Check your state's treatment separately.
How do I prove the company qualified?
Through company records on gross assets and business activity at issuance. A written attestation obtained contemporaneously is far easier than reconstructing it later.
Where to go next
For the default treatment of gains, read capital gains tax explained. For related planning, estate tax exemption and direct indexing explained.