Glossary/Acceleration (Vesting)
Legal & Governance

Acceleration (Vesting)

A provision that speeds up the vesting of equity, typically triggered by an acquisition or termination.

Full Definition

Acceleration in the context of equity vesting refers to provisions that speed up the vesting schedule, allowing a founder or employee to receive their equity faster than the original schedule. Acceleration is typically triggered by specific events like a company acquisition or termination.

Types of Acceleration

  • Single Trigger: Acceleration upon one event (usually acquisition). All or a portion of unvested shares vest immediately when the company is acquired.
  • Double Trigger: Acceleration requires two events (usually acquisition + termination within 12-24 months). More common and considered more balanced.

Common Terms

  • Single trigger: 25-100% acceleration upon acquisition
  • Double trigger: 50-100% acceleration upon acquisition + involuntary termination
  • Partial acceleration: Only a portion of unvested shares accelerate

Single vs Double Trigger Acceleration

FeatureSingle TriggerDouble Trigger
Events Required1 (acquisition only)2 (acquisition + termination)
When equity vestsImmediately at acquisitionOnly if terminated after acquisition
Typical acceleration25-100%50-100%
Founder preferenceStrongly preferredMore common, balanced
Investor preferenceResistedAcceptable

Real-World Example

A CTO with double-trigger acceleration has 50% of their unvested shares vest when the company is acquired and they are terminated within 12 months.

Frequently Asked Questions

What is single trigger acceleration?
Single trigger acceleration means all or a portion of unvested equity vests upon a single event — typically a company acquisition. This protects founders and employees from losing unvested shares when the company is sold.
Why do investors prefer double trigger?
Investors prefer double trigger because it keeps key employees incentivized to stay after an acquisition. With single trigger, employees could leave immediately after the deal closes, potentially harming the acquiring company and reducing the deal value.
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Acceleration (Vesting): Definition & Examples | Datapile