Single-Trigger Acceleration

Single-Trigger Acceleration (Summary)

Single-trigger acceleration speeds up vesting when a single event happens: the company is acquired. When the acquisition closes, all (or a defined portion of) your unvested equity vests immediately, regardless of whether you:

• Stay employed, or
• Are fired or pushed out shortly after the deal.

Why It’s a Mixed Bag

• Employee upside: You can walk away with more equity value at the moment of acquisition.
• Deal downside: You become more expensive for an acquirer to retain because:
  • Your equity is already fully vested.
  • They’ll likely need to issue new equity to keep you.
• Acquirers factor this extra cost into the purchase price or may walk away from the deal entirely.
• Founders/investors sometimes like single-trigger because it simplifies negotiations with acquirers, but it can hurt you if you’re terminated soon after closing.

Example

You join a seed-stage startup with:

• 1% equity
• 4-year vesting with a 1-year cliff

After 18 months, the company is acquired for $60M.

With single-trigger acceleration:

• Remaining 30 months of unvested equity vests immediately.
• You now own the full 1%.
• Payout: 1% × $60M = $600,000.

Without acceleration:

• Vested: 18 / 48 months = 37.5% of your grant.
• You own 0.375%.
• Payout: 0.375% × $60M = $225,000.
• The acquirer doesn’t need to give you new equity just to make you whole.

Trade-off:

• Single-trigger gave you $375,000 more in this scenario.
• But it may have made the acquisition harder to close or reduced the price because of higher retention costs.

What to Watch Out For

• Single-trigger can backfire.
  • Some acquirers avoid deals where key employees fully vest on day one because retention economics don’t work.
• Less common than double-trigger.
  • Many modern, employee-friendly and deal-friendly setups use double-trigger acceleration, which requires:
    1. An acquisition, and
    2. Your termination (often without cause) or a qualifying resignation.
• Ask about a “good reason” clause.
  • If you have single-trigger, negotiate a definition of good reason (e.g., demotion, pay cut, forced relocation) so that if you resign for cause, you still get acceleration.
• Expect equity renegotiation post-acquisition.
  • If you’re fully vested on day one, the acquirer has less leverage to retain you with existing equity.
  • They may:
    • Offer a new grant with its own vesting, or
    • Push for changes to your existing package.

Related Terms

• Double-Trigger Acceleration – Acceleration only if there’s an acquisition and you’re terminated (or leave for good reason). Generally more balanced for both employees and acquirers.
• Vesting Acceleration – The broader concept of speeding up vesting schedules under certain conditions (single-trigger, double-trigger, or other custom structures).