Single-trigger acceleration vests unvested equity when a single defined event happens—almost always a change of control—regardless of whether the employee stays or leaves.

How it works

Imagine an engineer with two years of unvested options. The company sells to a strategic buyer. Under single trigger, those options vest fully at signing or close, and the employee can exercise and participate in proceeds (subject to the deal’s treatment of options). The acquirer cannot use the old vesting clock to keep that person tied to the earn-out.

Founders sometimes receive single trigger on a slice of their founder shares in early negotiations. Broad single trigger across the whole employee pool is rarer in venture-backed companies because it raises the effective purchase price and reduces post-close retention hooks. Buyers may demand option repricing, cash bonuses instead, or partial acceleration only for key roles.

Why it matters

• Founders: Granting company-wide single trigger can torpedo M&A terms. Use it sparingly and document who has it before you shop the company.
• Operators: If you have single trigger, understand tax timing—exercising options at close may create AMT or ordinary income you must fund immediately.
• Investors: Deal teams model acceleration as part of net proceeds. Hidden single triggers have killed deals at the eleventh hour.

Common mistake

Employees assuming they have single trigger because “that’s fair in a sale.” Most standard venture templates use no acceleration or double trigger unless explicitly negotiated.

Related ideas

Change-of-control clauses, option treatment in mergers, retention packages, and vesting schedules.