Comparison
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Single Trigger vs Double Trigger Acceleration
Quick Answer
Single trigger acceleration vests all unvested equity upon one event (usually an acquisition), while double trigger requires two events (acquisition PLUS termination) before equity accelerates.
What is Single Trigger Acceleration?
Single trigger acceleration automatically vests some or all unvested equity when a single event occurs — typically a change of control (acquisition). If a company with single trigger provisions is acquired, all covered equity immediately vests regardless of whether the employee continues working at the acquirer. This is highly favorable to the equity holder and relatively uncommon except for founders and C-suite executives.
What is Double Trigger Acceleration?
Double trigger acceleration requires two events before unvested equity accelerates: first, a change of control (acquisition), and second, an involuntary termination or constructive dismissal within a specified period (usually 12-18 months after the acquisition). This structure protects employees from being acquired and then fired to avoid paying out their equity, while still incentivizing them to stay and help with the transition.
Key Differences
| Feature | Single Trigger Acceleration | Double Trigger Acceleration |
|---|---|---|
| Events Required | One event — typically change of control (acquisition) | Two events — change of control AND involuntary termination |
| When Equity Vests | Immediately upon the acquisition closing | Only if terminated without cause (or constructive dismissal) after acquisition |
| Retention Incentive | None — employee is fully vested and can leave immediately | Strong — employee stays to continue vesting under the acquirer |
| Acquirer Preference | Strongly disfavored — creates flight risk and upfront cash obligation | Preferred — keeps key employees incentivized to stay post-acquisition |
| Who Gets It | Typically founders, CEOs, and C-suite only | More broadly available — sometimes all employees with equity |
| Impact on Deal | Can reduce acquisition price or kill deals — acquirers see it as a liability | Deal-friendly — acquirers accept it as reasonable employee protection |
| Market Standard | Not standard — considered aggressive by most investors | Industry standard — widely accepted as fair and balanced |
When Founders Choose Single Trigger Acceleration
- →Founders and CEOs sometimes negotiate single trigger acceleration because an acquisition may eliminate their role entirely. If you're a founder with significant unvested equity and an acquisition would remove you as CEO, single trigger ensures you're compensated for the value you created.
When Founders Choose Double Trigger Acceleration
- →Double trigger should be the default for almost everyone. It protects employees from the 'acqui-fire' scenario (being acquired then terminated to avoid equity payouts) while keeping acquirers comfortable that key talent will stay. Most investors and boards prefer this structure.
Example Scenario
A CTO has 100,000 unvested shares when the company is acquired. With single trigger: all 100,000 shares vest immediately at closing. The CTO can leave the next day, fully compensated. With double trigger: the 100,000 shares continue their normal vesting schedule under the acquirer. If the acquirer fires the CTO without cause at month 6, all remaining unvested shares accelerate. If the CTO voluntarily quits, they forfeit unvested shares.
Common Mistakes
- 1Founders accepting double trigger when they should push for single trigger (especially if the acquirer plans to eliminate their role). Employees not understanding that double trigger ONLY protects against involuntary termination — quitting doesn't trigger acceleration. Not defining 'constructive dismissal' clearly (major role change, relocation, compensation cut). Acquirers not factoring single trigger acceleration into their offer price.
Which Matters More for Early-Stage Startups?
Double trigger matters more for the ecosystem because it's the balanced structure that makes deals work. Single trigger is a powerful tool but should be used sparingly — it can complicate or kill acquisitions. For individual employees, double trigger provides meaningful protection against the most common post-acquisition risk (being let go) without the downsides that single trigger creates.
Related Terms
Frequently Asked Questions
What is Single Trigger Acceleration?
Single trigger acceleration automatically vests some or all unvested equity when a single event occurs — typically a change of control (acquisition). If a company with single trigger provisions is acquired, all covered equity immediately vests regardless of whether the employee continues working at the acquirer. This is highly favorable to the equity holder and relatively uncommon except for founders and C-suite executives.
What is Double Trigger Acceleration?
Double trigger acceleration requires two events before unvested equity accelerates: first, a change of control (acquisition), and second, an involuntary termination or constructive dismissal within a specified period (usually 12-18 months after the acquisition). This structure protects employees from being acquired and then fired to avoid paying out their equity, while still incentivizing them to stay and help with the transition.
Which matters more: Single Trigger Acceleration or Double Trigger Acceleration?
Double trigger matters more for the ecosystem because it's the balanced structure that makes deals work. Single trigger is a powerful tool but should be used sparingly — it can complicate or kill acquisitions. For individual employees, double trigger provides meaningful protection against the most common post-acquisition risk (being let go) without the downsides that single trigger creates.
When would you encounter Single Trigger Acceleration vs Double Trigger Acceleration?
A CTO has 100,000 unvested shares when the company is acquired. With single trigger: all 100,000 shares vest immediately at closing. The CTO can leave the next day, fully compensated. With double trigger: the 100,000 shares continue their normal vesting schedule under the acquirer. If the acquirer fires the CTO without cause at month 6, all remaining unvested shares accelerate. If the CTO voluntarily quits, they forfeit unvested shares.
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