Founder Vesting Explained: Standard Terms & Traps (2026)

How founder vesting works, why 4-year with a 1-year cliff is standard, acceleration clauses.

Founder Vesting Explained

Founder vesting protects the company from a co-founder leaving early with a large equity stake. It also protects each co-founder from the same happening to them. The details — cliff, acceleration, reset — determine who wins if things go sideways.

The standard: 4 years with 1-year cliff

Equity vests linearly over 4 years, with a 12-month cliff before any equity vests at all. If a founder leaves before month 12, they get nothing. Between months 12 and 48, equity vests monthly. This is the market default.

Why vesting protects everyone

Without vesting, a co-founder who leaves after 6 months keeps 50% of the company forever. That kills the ability to raise (investors won't fund a company with a large absent shareholder) and demoralizes the founder who stays.

Single-trigger acceleration

All (or a portion of) unvested shares vest immediately on acquisition. Founder-friendly but investor-hostile — acquirers usually want founders locked in for 1–2 years post-acquisition. Rarely granted in full.

Double-trigger acceleration (standard)

Unvested shares accelerate only if two events happen: acquisition AND the founder is terminated without cause (or forced out) within 12 months of the acquisition. This is the standard and protects founders against post-acquisition purges.

The Series A reset trap

Investors sometimes reset founder vesting at Series A — restart the 4-year clock even if the founder has been at the company for 3 years. This effectively confiscates 3 years of earned vesting. Push back hard: credit for time served is standard, full reset is not.

Vesting after leaving

Standard: departing founder keeps vested shares and forfeits unvested. Some agreements include a repurchase option for the company to buy back vested shares at fair market value or the original price — read carefully.

Frequently asked questions

Should I have vesting if I'm a solo founder?
Yes, before you take investment. Investors will require it. Setting it up preemptively means you set the terms.
Can co-founders have different vesting?
Yes, but usually the same schedule with different equity amounts. Different schedules signal distrust.
What if a co-founder is fired before the cliff?
They leave with nothing. This is the point of the cliff — it forces the co-founder decision to be made honestly in the first year.

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