Vesting acceleration is the contractual mechanic that vests some or all of an equity holder's unvested shares upon defined trigger events. It applies to stock options, restricted stock, founders stock, and RSUs, with two primary structures: single-trigger (acceleration on a change of control alone) and double-trigger (acceleration only if the holder is also terminated without cause or resigns for good reason within a defined window). It is a critical equity-grant term that determines how much of an executive's or employee's equity actually pays out in an exit scenario.
The two main structural flavors: