Acceleration (single-trigger)
Also: single-trigger acceleration, single trigger, change-of-control acceleration
A contract provision that vests some or all unvested equity on a single event, typically a change of control, without requiring a subsequent termination.
Single-trigger acceleration vests equity on one event. In practice that event is almost always a change of control: acquisition, merger, or majority recapitalization. No termination of employment is required. The award accelerates whether the executive stays, leaves, or is retained by the acquirer. Single-trigger is unusual below the C-suite because it creates retention risk for the buyer.
Example: a VP of Engineering with 40,000 unvested RSUs and a single-trigger provision sees the company acquired in a $3.2 billion deal. All 40,000 RSUs vest at closing at the deal price of $42 per share, producing $1.68 million of ordinary wage income subject to 37% federal supplemental withholding.
Common mistake: assuming “acceleration on change of control” means single-trigger. Most grants use double-trigger, which requires both a change of control and a qualifying termination. Read the specific grant agreement, not the summary plan description.
Single-trigger provisions matter in offer negotiation for senior hires at pre-IPO companies, and at closing of a deal where the tax spike needs planning against the cash component of the transaction consideration.