A share vesting agreement is a contract between a company and an individual, usually a founder, employee, or advisor, that controls when granted equity actually becomes theirs. Instead of transferring shares outright, the company releases them in portions tied to continued service or specific milestones. The standard structure runs four years with a one-year cliff, and the fine print inside the agreement shapes tax liability, what happens in an acquisition, and what the company can reclaim if the participant leaves.
Why Companies Use Vesting
The core problem vesting solves is the departing co-founder. Split a company 50/50 with someone who walks away three months later, and without vesting that person still owns half the company forever. Vesting turns ownership into something earned over time rather than handed over on day one.
Investors expect it. Venture capital firms almost always require founders to have vesting schedules in place before they’ll invest. If vesting already exists when a VC arrives, the investor will often accept the existing terms; if it doesn’t, the investor proposes their own, and those tend to be less favorable to founders. Setting up vesting before fundraising keeps the terms in the founders’ hands.
Vesting also works as a retention tool. Equity that vests over four years gives people a financial reason to stay, and gives the company a structured way to reclaim shares from anyone who leaves early.
The Four-Year Schedule and the One-Year Cliff
The standard time-based schedule runs four years with a one-year cliff. During the cliff, nothing vests. If someone leaves or is let go within the first twelve months, they walk away with zero equity. On the cliff date, a full quarter of the granted shares vest at once.
After that, the remaining 75% vests in equal monthly or quarterly installments. Monthly vesting on a four-year schedule works out to 1/48th of the grant each month. At the four-year mark, the participant owns every share in the grant.
Until shares vest, they remain subject to forfeiture. The participant has no legal claim to unvested shares, and the company can reclaim them when service ends.
Performance-Based Vesting
Not every schedule runs on the calendar. Performance-based vesting ties equity to specific business objectives instead of, or on top of, time served. Common milestones include revenue targets, major product launches, profitability, or closing strategic partnerships. For leadership roles, vesting might link to annual recurring revenue growth or market expansion.
The upside is direct alignment between someone’s equity and the outcomes they’re supposed to drive. The downside is complexity. Time-based milestones are binary; performance milestones need clear definitions upfront. What counts as hitting a revenue target if the company pivots? Who decides whether a milestone has been met? Those questions need answers in the agreement, not after a dispute. Many companies use a hybrid: a time-based schedule with performance accelerators that speed things up if goals are reached early.
Acceleration in a Sale or Change of Control
Acceleration clauses override the normal timeline and grant immediate ownership when specific events happen. They protect people whose equity could otherwise be wiped out by an acquisition or restructuring they had no hand in.
Single-Trigger Acceleration
Single-trigger acceleration vests all or part of unvested shares the moment the company is sold or undergoes a change of control. One event, one trigger. The participant doesn’t have to be terminated or affected in any other way.
Acquirers and investors dislike this. A buyer wants the team to stay after the deal closes, and if everyone’s equity is already fully vested on day one, the financial reason to stick around drops. For that reason, single-trigger acceleration is uncommon in practice.
Double-Trigger Acceleration
Double-trigger acceleration requires two events. The first is a change of control. The second is the participant being terminated without cause, or forced to resign for good reason (a significant pay cut, demotion, or required relocation), within a set window after the acquisition, commonly three to twelve months.
This is the market standard. The acquirer keeps the team motivated with unvested equity, and the equity holder gets protection against being fired by new management just to reclaim shares. If both triggers occur, the remaining unvested equity vests in full.
What Happens to Shares When You Leave
Termination triggers the most consequential provisions in the agreement. The general rule: unvested shares are forfeited or repurchased by the company, and vested shares belong to you. The details depend on how and why you left.
Repurchase of Unvested Shares
When service ends, the company either automatically reclaims unvested shares or exercises a repurchase option to buy them back at the original purchase price, which for early-stage restricted stock is often a fraction of a penny per share. The repurchase window is typically 90 days from the termination date, though some agreements allow up to 120.1U.S. Securities and Exchange Commission. EX-10.3.2 Stock Option Agreement If the company misses that window, the former participant may keep the unvested shares, which is why tracking the deadline matters.
Vested Shares and Right of First Refusal
Vested shares are yours after departure, but most agreements restrict your ability to sell them. A right of first refusal gives the company, and sometimes existing investors, the option to buy your vested shares at the offered price before you sell to an outsider.2U.S. Securities and Exchange Commission. Right of First Refusal and Co-Sale Agreement This keeps the ownership group tight and prevents strangers from landing on the cap table without consent.
Good Leaver, Bad Leaver
The reason for departure changes the outcome. A good leaver, someone laid off, retiring, or leaving due to illness or disability, generally keeps all vested shares and forfeits only the unvested portion. A bad leaver, someone fired for serious misconduct, in breach of contract, or violating non-compete obligations, faces harsher consequences. Some agreements let the company repurchase even vested shares from a bad leaver, sometimes at the original purchase price rather than fair market value. Define these categories precisely so there’s no ambiguity about which bucket a departure falls into.
Permitted Transfers
Most agreements lock down share transfers but carve out exceptions for estate planning. Common permitted transfers include gifts to immediate family, transfers to family trusts, and distributions through a will or inheritance. The transferee typically becomes bound by the same restrictions as the original holder, including repurchase rights and rights of first refusal.
Taxes and the 83(b) Election
This is where people lose the most money, and it’s entirely preventable. Under federal tax law, when you receive restricted stock in exchange for services, you owe income tax on the difference between what you paid and the shares’ fair market value. The question is when that bill hits.
The Default: Taxed at Each Vesting Date
Without an election, you’re taxed each time shares vest. The taxable amount is the fair market value on the vesting date minus what you paid for them.3Office of the Law Revision Counsel. 26 USC 83 – Property Transferred in Connection With Performance of Services For a startup that’s grown quickly over four years, the shares could be worth dramatically more at vesting than at the grant date. That appreciation gets taxed as ordinary income, at rates that can exceed 35% federally.
The 83(b) Election Flips the Timing
Section 83(b) lets you pay income tax on the full value of all the shares at the time of grant, even though most haven’t vested.3Office of the Law Revision Counsel. 26 USC 83 – Property Transferred in Connection With Performance of Services For an early-stage founder who paid a fraction of a penny per share when the company was worth almost nothing, the tax bill is negligible. Future appreciation then qualifies for long-term capital gains treatment when you eventually sell, at significantly lower rates than ordinary income.
The catch: the election must be filed with the IRS within 30 days of the stock transfer. No extensions. You file by mailing the completed IRS Form 15620 to the IRS office where you file your tax return, and you must also send a copy to the company.4Internal Revenue Service. Form 15620 – Section 83(b) Election Miss the deadline and you’re stuck with the default rule. For founders receiving restricted stock at incorporation, the election is almost always worth filing because the tax owed at that point is close to zero.
One risk: if you file an 83(b) election and later forfeit the shares by leaving before they vest, you don’t get a tax deduction for the loss. You paid tax on shares you never actually owned. For most early-stage grants where initial value is negligible, this downside is minimal. For grants where the stock already has meaningful value, it requires careful analysis.
409A Valuations and Rule 701 Compliance
Two federal regimes sit behind every equity grant and quietly determine whether the paperwork holds up.
Any company granting stock options must set the exercise price at or above the stock’s fair market value on the grant date. Section 409A imposes steep penalties for getting this wrong. If the IRS finds options were granted below fair market value, the option holder (not the company) faces a 20% excise tax on the deferred compensation plus an interest penalty calculated from the year the options first vested.5Office of the Law Revision Counsel. 26 USC 409A – Inclusion in Gross Income of Deferred Compensation Under Nonqualified Deferred Compensation Plans To create a safe harbor, private companies hire independent appraisers to conduct a 409A valuation, generally valid for 12 months. A material event, a new funding round, a major customer contract, a significant business-model shift, requires a fresh valuation regardless of how recent the last one was.
Issuing equity is issuing securities. Most private companies rely on Rule 701, which exempts equity issued under a written compensation plan from federal registration as long as the company is not a public reporting entity.6eCFR. 17 CFR 230.701 – Exemption for Offers and Sales of Securities Pursuant to Certain Compensatory Benefit Plans and Contracts If total securities sold under the exemption exceed $10 million in any 12-month period, the company must provide enhanced disclosures to all recipients, including a summary of the plan terms, risk factors, and financial statements prepared under GAAP. Failing to provide those disclosures costs the exemption for every grant made during the entire 12-month period, not just the ones after the threshold was crossed. State-level securities laws (often called blue sky laws) add another layer, with filing requirements and fees that vary by jurisdiction.
What to Include in the Agreement
Ambiguity in a vesting agreement surfaces at the worst possible time: during a termination dispute, an acquisition, or a tax audit. Before drafting, nail down the following.
- Full legal name and address of the participant, matching government-issued identification.
- The exact number of shares granted, verified against the company’s authorized share pool, and the price per share based on the most recent 409A valuation or board-determined fair market value.
- The total vesting period, cliff duration, and whether vesting occurs monthly or quarterly after the cliff.
- Both the grant date and the vesting start date, which can differ if someone started working before the paperwork was completed. Both affect tax deadlines, including the 30-day window for an 83(b) election.
- Acceleration terms: single-trigger, double-trigger, or none.
- Repurchase provisions covering the repurchase price for unvested shares, the exercise window, and any repurchase rights on vested shares.
- Clear definitions of cause, good reason, and the good leaver versus bad leaver distinction.
Leaves of Absence
Address what happens to vesting during unpaid leave. The standard approach pauses vesting during unpaid leave and extends the schedule by the length of the leave. Some agreements let vesting continue during short leaves (under 90 days) and pause only for extended absences. Without explicit language, disputes are inevitable when someone returns from parental or medical leave and the two sides disagree about how much has vested.
Spousal Consent
In community property states, a spouse may have a legal interest in shares acquired during the marriage. A spouse who never signed the agreement could later challenge transfer restrictions or repurchase rights. Collecting a spousal consent at the time of the grant binds the spouse’s community property interest to the agreement’s terms and prevents that problem from surfacing during a divorce or the equity holder’s death.
Board Approval and Records
The board of directors must formally approve the share issuance and the terms of the vesting agreement before anyone signs, either through a written board consent or in the minutes of a board meeting. Skipping this step can call the validity of the grant into question.
Once approved, the agreement goes to the participant for signature, typically through an electronic platform that creates a timestamped audit trail. After both parties sign, the company should update its cap table software immediately and store the executed agreement in corporate records permanently. These documents get pulled during due diligence in every financing round and acquisition, and a missing agreement creates problems that are far easier to prevent than to fix.