Vesting Schedule Explained: Cliffs & Founder Vesting

Give someone equity and one clause decides whether that promise is safe: the vesting schedule. Without it, a co-founder or early hire can join, hold shares outright from day one, and leave a month later owning the same stake as someone who stayed for years.

This guide covers what vesting actually is, the standard four-year structure with a one-year cliff, why investors make founders vest their own stock too, and how acceleration clauses work when a company is acquired.

What a vesting schedule is, and why it exists

A vesting schedule is the timetable that governs when someone actually earns the equity or options they've been granted. Shares or options can be issued on day one, but ownership of them is conditional — you only keep them by staying involved for a set period. Leave early, and the unvested portion is forfeited and returns to the company.

The reason is simple: equity is meant to reward the people who build the company, not people who show up briefly and leave. Without vesting, an employee stock option plan would be useless as a retention tool — anyone could accept a grant, contribute nothing, and walk away with a stake anyway. Tying ownership to time protects the company, the rest of the team, and eventually the investors who need to know the people they backed are still around.

Shares vs options: does vesting work the same way?

The mechanics differ slightly depending on what's vesting. Founder and employee shares usually exist from day one, with vesting enforced through a repurchase right — the company can buy back any unvested shares at cost if someone leaves. That's why founder vesting is called reverse vesting: the shares came first, and vesting is what removes the company's right to claw them back. Stock options work the other way round. The option itself only becomes exercisable as it vests, so there's nothing to repurchase — unvested options simply lapse and are never exercisable at all.

The end result is the same either way: only the vested portion survives an early departure. But the paperwork differs, and it's worth knowing which one you've signed. A stock option agreement references a vesting schedule that controls when options become exercisable. A founder or restricted stock agreement uses the same structure to control when the company's repurchase right lapses, share by share.

The standard structure: four years, one-year cliff

Almost every startup vesting schedule follows the same shape: 4-year vesting with a 1-year cliff. Nothing vests during the first twelve months — this is cliff vesting. At the twelve-month mark, a lump sum vests all at once, typically 25% of the total grant. After that, the remaining 75% vests in equal instalments, usually monthly, over the following three years.

Cliff vesting exists specifically to protect the company from someone who joins, contributes little, and leaves within the first year. A hire who doesn't work out and departs in month three costs nothing in equity terms, because the cliff was never reached. It's a blunt rule, but it's the market default, and any employee equity grant worth signing will use some version of it.

Founder vesting: earning your own shares back

It sounds strange the first time you hear it: investors will often insist that founders vest their own shares, even though those shares were issued — and sometimes already fully paid for — before any investor showed up. This is reverse vesting. Instead of shares vesting as they're granted, a founder's existing stock is subject to a repurchase right the company can exercise over any unvested portion if that founder leaves early.

Investors ask for founder vesting because an unvested cap table is a real risk. A pattern we see often: two co-founders incorporate with 10,000,000 shares split evenly, no vesting agreed anywhere. Six months in, one co-founder takes a job elsewhere. Under what is a cap table rules with no vesting attached, they still own 5,000,000 shares — half the company — with no obligation to do anything further for it. The founder who stayed has no leverage to bring in a replacement or recover that equity for the option pool.

Reverse vesting on the standard 4-year, 1-year-cliff timeline fixes this: a founder who leaves early keeps only the fraction of the company they've actually earned, and the rest returns for reallocation. It's worth setting up voluntarily, before any money is raised, even between just two or three co-founders — it protects co-founders from each other, not only from outside investors, and it's a near-universal term in the venture financing documents published by the NVCA.

A worked example: leaving right around the cliff

Timing near the cliff matters more than almost any other date in a grant's timeline. Take two employees granted 36,000 options each, on the same 4-year schedule with a 1-year cliff and $1.00 strike price, who both leave the company within weeks of the twelve-month mark.

Credit for time already served

Co-founders sometimes negotiate credit for work already done before incorporation — a few months of unpaid product-building before the company legally existed, for example. Rather than starting the clock from zero, the vesting start date is set back to when the work actually began, so the cliff and every milestone after it land earlier. This is common but never automatic: it has to be agreed and documented explicitly, it's usually capped at 6-12 months, and investors will look closely at a long credited period during due diligence, since it effectively pre-vests equity before any outside money was at risk.

Accelerated vesting: single-trigger vs double-trigger

Acceleration clauses change what happens to unvested shares in specific events, most commonly an acquisition. Single trigger vesting accelerates some or all of a person's unvested shares immediately when the triggering event happens, regardless of what happens to their job afterwards.

Double trigger vesting needs two events before acceleration kicks in: the company is acquired, and the employee is terminated without cause — or resigns for good reason — within a defined window afterwards, commonly twelve months. Double trigger is far more common in practice, especially for founders and executives, because acquirers generally want the option to retain key people after closing rather than watch equity vest away the moment the deal signs.

Single trigger acceleration is less popular with buyers for exactly that reason — it removes the retention incentive equity is meant to provide, which can make a company less attractive to acquire, or push the price down to compensate. Most negotiated founder and executive agreements settle on double trigger, often with partial acceleration — commonly 50% of the remaining unvested shares — rather than full acceleration, as a middle ground. Investopedia has a useful plain-English breakdown of both structures if you want a second explanation before a negotiation.

What's actually negotiable

The 4-year vesting, 1-year cliff structure is a strong default, not a legal requirement. Founders and senior hires can, and regularly do, negotiate around the edges of it.

• Cliff length — some agreements use a 6-month cliff instead of 12, though 1 year remains the norm
• Vesting cadence after the cliff — monthly is standard, though some grants vest quarterly instead
• Acceleration — how much, if any, accelerates on a single or double trigger, and what percentage
• Post-termination exercise window — often extendable well beyond the default 90 days for vested options

None of these change the total size of a grant. What they change is how quickly, and under what circumstances, that grant becomes irreversibly someone's own — which is worth spending negotiating time on, especially for a senior hire joining before a Series A.

Vesting for advisors and contractors

Advisors and contractors are rarely put on the full 4-year vesting timeline founders and employees use. A common pattern is 2-year vesting, sometimes with no cliff at all or a shorter 3-month one, reflecting a lighter, more time-boxed commitment than a full-time hire. Grant sizes are also much smaller — often a fraction of a percent — since the expected time input is a few hours a month rather than a full-time role. The core mechanic is unchanged: unvested equity is still forfeited if the relationship ends early, and it's still worth writing the schedule down explicitly rather than assuming it's understood.

Vesting on the cap table

Every option or share subject to a vesting schedule sits on the fully diluted cap table from the grant date, even though most of it isn't earned yet. This matters when understanding equity dilution: unvested shares still count toward fully diluted totals for valuation and ownership-percentage purposes, but they can still be clawed back if someone leaves early. That's exactly why tracking vested and unvested positions separately matters more than just looking at headline grant size.

It's also why an option pool needs headroom beyond current headcount. Unvested shares that get forfeited return to the pool and get re-granted, so a pool sized only against people already hired runs out faster than expected once ordinary departures are factored in.

Whether you're setting founder vesting before incorporation or sizing option grants for new hires, the underlying maths — cliffs, monthly vesting, forfeiture, acceleration — is the same every time. Foundily's option pool calculator runs the grant and pool numbers for you, so the vesting schedule you put in front of a co-founder or a candidate is grounded in real shares and real percentages, not a template nobody checked.