Cliff Vesting Explained for Startup Founders and Employees

Cliff vesting makes equity an all-or-nothing proposition for an initial period. Nothing vests before the cliff date; a defined block vests when that date is reached. Vesting usually continues in smaller increments afterward.

For venture-backed startups, the familiar structure is four years of vesting with a one-year cliff. That is a convention, not a legal requirement. Carta describes this as the usual schedule for VC-backed corporations, while Cooley notes that founders can choose another cliff period and may receive credit for documented work performed before incorporation (Carta, Cooley GO).

A one-year cliff in numbers

Suppose an employee receives 48,000 options under a four-year schedule that starts January 1, 2027:

Date	Vested options	What changed
December 31, 2027	0	The cliff has not been reached
January 1, 2028	12,000	25% vests at the first anniversary
July 1, 2028	18,000	Six more monthly installments of 1,000 have vested
January 1, 2031	48,000	The grant is fully vested

Leaving one day before the cliff would ordinarily mean vesting none of this grant. Remaining in continuous service through the cliff date would vest the first 12,000 at once. One filed option agreement illustrates this mechanism: 25% on the first anniversary of the vesting start date and 1/48 of the original grant monthly afterward, subject to continued service (SEC exhibit).

The agreement—not the shorthand “four years with a one-year cliff”—controls. It should identify the vesting start date, what counts as continuous service, the post-cliff cadence and how fractional shares are rounded.

The mechanism depends on the equity instrument

A cliff does not operate identically across every form of equity:

• Standard stock options: Before vesting, the holder generally cannot exercise the option unless the grant permits early exercise. After departure, vested options may remain exercisable only for the period stated in the plan and grant documents. The cliff does not determine that post-termination window.
• Restricted founder stock: Shares may be issued at formation, but the company can typically repurchase the unvested portion if the founder leaves. The repurchase right lapses according to the vesting schedule. Cooley describes a common founder arrangement as monthly or quarterly vesting over four years, with unvested shares repurchased at the lower of cost or then-current fair market value (Cooley GO).
• Early-exercised options: The holder buys shares before the underlying option has vested. Those shares remain on the option’s vesting schedule and are generally subject to company repurchase if service ends early (Cooley GO).
• RSUs: The award terms may require continued service and a separate milestone, such as an IPO, before the recipient owns the shares. Reaching a service cliff therefore does not necessarily produce shares that can be sold (Carta).

This distinction matters when someone says, “I lose my equity before the cliff.” An optionholder may lose an unvested right to buy shares. A founder may already hold shares but be required to sell the unvested portion back under a contractual repurchase right.

Why founders use a cliff

The cliff limits dead equity. If a co-founder or early hire leaves after a short period, they do not retain a material stake intended to reward years of work. For co-founders, it addresses the “free rider” problem: without vesting, an early departure could keep the entire original allocation (Cooley GO).

But a cliff also creates a sharp boundary. A departure shortly before the anniversary may move a meaningful grant from 25% vested to zero. Founders should settle the policy before a relationship deteriorates, not during a departure.

Terms to settle before issuing equity

Document these points explicitly:

1. Vesting commencement date. Is it incorporation, the grant date or an earlier date reflecting documented work?
2. Cliff and total term. A one-year cliff over four years is common, but it may not fit a short project or an advisor relationship.
3. Vesting after the cliff. State whether vesting occurs monthly, quarterly or annually.
4. Departure treatment. Define what happens upon resignation, termination, death, disability or a change from employee to advisor.
5. Acceleration. Single-trigger acceleration vests some or all covered equity upon one event, commonly a company sale. Double-trigger acceleration also requires a second event, commonly a qualifying termination after the sale. Double-trigger terms can protect the holder after an acquisition while preserving some retention value for the buyer (Carta).
6. Administration. Make the board approval, cap-table record and signed grant or purchase agreement agree. A spreadsheet is not a substitute for the governing documents.

These choices belong beside ownership, IP and departure provisions in a founders agreement worksheet, then in counsel-prepared company documents.

Do not miss the US Section 83(b) issue

For US taxpayers, restricted stock and stock acquired through early exercise can create a separate tax decision. Without an election, substantially nonvested property received for services is generally included in income when it becomes substantially vested, based on fair market value at that time minus the amount paid. A Section 83(b) election instead includes the spread at transfer, so later appreciation generally is not compensation income as the property vests (IRS Publication 525).

The election must be filed no later than 30 days after the property transfer—not 30 days after the cliff—and generally cannot be revoked without IRS consent. The IRS provides Form 15620 and filing instructions (IRS Form 15620).

An election is not automatically beneficial. If the property is later forfeited, the IRS says the loss is generally the amount paid minus any amount realized on forfeiture; the amount previously included as compensation does not itself become the deductible loss. Nor should someone assume that merely receiving an ordinary, unexercised option starts an 83(b) deadline: the election concerns transferred substantially nonvested property, such as restricted shares or shares acquired through early exercise. Equity holders should review the instrument and filing deadline with a qualified tax adviser.

Cliff vesting is simple arithmetic but consequential contract design. Specify the instrument, start date, cliff event, departure mechanics and tax workflow; otherwise, “one year” can conceal several different outcomes.