An ESOP grant is a promise, not a payout. Startups issue stock options to employees as part of compensation, but those options are not simply handed over on day one. They vest over time, and the exact shape of that vesting schedule determines how much an employee actually keeps if they leave the company early, get let go, or stay for the long haul.
What Vesting Actually Means
Vesting is the process by which an employee earns the right to exercise, meaning buy, the options they were granted, spread out over a period of time rather than all at once. Until an option vests, the employee has no right to purchase the underlying shares. If they leave before an option vests, that portion of the grant is simply forfeited back to the company's option pool.
The Standard Four-Year Schedule With a One-Year Cliff
The most common startup vesting schedule is four years with a one-year cliff. The cliff means the employee vests nothing at all for the first year. If they leave before their first anniversary, they walk away with zero options from that grant, regardless of how large the grant was. After the cliff, a large chunk, commonly a quarter of the total grant, vests all at once, and the remainder vests monthly or quarterly over the following three years until the full grant is vested at the four-year mark.
Why the Cliff Exists
The cliff protects the company and existing shareholders from a scenario where someone joins, receives a meaningful equity grant, and leaves within a few months having contributed very little, while still walking away with vested equity. It is a filtering mechanism as much as a compensation structure.
Exercising Options After They Vest
Vesting only grants the right to buy shares at a fixed exercise price, usually set at the fair market value on the grant date. The employee still has to pay to exercise, and in most jurisdictions that purchase can trigger a tax event even before the shares are ever sold. Employees sometimes discover, only when they try to exercise, that the cost of buying the shares plus the associated tax bill is a real cash outlay, not a formality.
What Happens If You Leave Before Full Vesting
Any unvested portion of the grant is forfeited immediately on departure, with no exceptions unless the specific plan or an individual agreement says otherwise. The vested portion is a different story, and this is where the post-termination exercise window matters. Most option plans give a departing employee a limited window, commonly 90 days, to exercise their already-vested options before they are cancelled entirely. If the employee cannot afford to exercise and pay any associated tax within that window, they can lose vested options they otherwise earned. Some companies now offer extended exercise windows precisely because the standard 90-day window has pushed departing employees to forfeit equity they had already vested.
Acceleration Clauses
Some option grants include acceleration provisions that speed up vesting under specific conditions, most commonly a sale of the company. A single-trigger acceleration vests some or all outstanding options automatically when the company is acquired. A double-trigger acceleration requires both an acquisition and a qualifying termination, such as being let go without cause after the acquisition, before acceleration applies. Double-trigger is far more common in modern grants because it protects employees from being pushed out right after an acquisition while still requiring an actual change of control to trigger the benefit.
Tax Treatment Varies by Jurisdiction and by Event
Exercising an option and later selling the resulting shares can each be separate taxable events, and exactly when tax is owed, and how much, depends heavily on local tax law, the type of option plan the company uses, and how long the shares are held before being sold. Employees should not assume the tax treatment they have heard about from a friend at a different company, in a different country, or under a different plan applies to their own grant. Checking with a tax professional before exercising a meaningful number of options is worth the cost, especially since exercising can create a tax liability before the shares themselves can be sold to cover it.
Secondary Sales and Company Buyback Programs
Vested options and shares are usually illiquid until the company is acquired or goes public, since there is normally no open market to sell into. Some companies run periodic buyback or secondary sale programs, allowing employees to sell a portion of their vested shares back to the company or to incoming investors at a valuation set by the company's latest round. These programs are not guaranteed, are entirely at the company's discretion, and typically come with their own eligibility rules and caps on how much any one employee can sell, so they should be treated as a possible future benefit rather than something to plan around.
How Vesting Interacts With Future Fundraising
Every option grant comes out of the company's option pool, and that pool is one of the levers that gets adjusted, usually expanded, as part of negotiating a term sheet for a new priced round. A larger pool set aside for future hires dilutes existing shareholders, including employees whose own options have already vested, which is one reason cap table mechanics and dilution compound in ways that are not always obvious from an offer letter alone.
What to Actually Ask Before Accepting an Equity Grant
Before accepting an equity-heavy offer, it is worth asking for the total number of fully diluted shares outstanding, not just the number of options offered, the current strike price, the length of the post-termination exercise window, and whether any acceleration provisions apply. These four data points, more than the headline number of options, determine what the grant is actually worth in most realistic outcomes. The same level of diligence an investor applies during a data room review of the cap table is worth applying to your own offer letter.