Executive Summary
What is double-trigger acceleration?
Double-trigger acceleration means your unvested stock options or RSUs vest automatically only when two events happen: (1) a change of control (your company is acquired or merges), and (2) you're terminated without cause—or you resign for good reason—within a set period (often 9–18 months) after the deal. If only the deal happens, nothing vests. If you're laid off after the sale, your unvested equity vests. It protects you from being let go with nothing.
Your company is being acquired. You've heard about "double-trigger" and "single-trigger" acceleration. What does it mean for you? In short: double-trigger protects you if the acquirer lays you off. Single-trigger vests everything at closing—but you might still get laid off, with a big tax bill and no job.
The bottom line: Double-trigger is the norm for most employees. Your unvested equity vests only if the deal closes and you're terminated (or quit for good reason) within a window after. Single-trigger vests everything at closing—no termination needed. That sounds great until you realize: the acquirer might lay you off anyway, and you've already paid tax on the vesting. See our vesting schedule guide and M&A equity guide.
Single-Trigger vs. Double-Trigger
| Single-Trigger | Double-Trigger | |
|---|---|---|
| When does unvested equity vest? | At deal close | Only if you're terminated (or quit for good reason) after the deal |
| First event | Change of control | Change of control |
| Second event | None | Termination without cause, or resignation for good reason |
| Typical window | N/A | 9–18 months after closing |
| Who usually gets it | Sometimes founders, key execs | Most employees |
Why Double-Trigger Exists
Acquirers want to keep key people after a deal. If everyone's equity vested at closing (single-trigger), they might leave right away—they've got their money. So acquirers prefer double-trigger: you only get acceleration if you're terminated. That gives them a reason to keep you—and if they do lay you off, you're protected.
For you: Double-trigger means you're not left empty-handed if the new owner cuts your job. Your unvested equity vests when you're let go. Single-trigger means you get a big vesting event at closing—and a big tax bill—but if you're laid off six months later, you get nothing extra.
What Counts as "Good Reason"?
"Good reason" is usually defined in your equity plan or employment agreement. Common triggers:
- Significant cut in pay or role
- Relocation requirement
- Loss of title or responsibility
- Material breach by the company
If you resign for good reason, it often counts like a termination without cause—your double-trigger can fire. Check your documents.
The Tax Angle
When equity vests (single or double-trigger), you owe tax. RSUs = ordinary income at vesting. Stock options = depends on type (ISO vs NSO). A single-trigger that vests $500,000 at closing can mean a $185,000+ tax bill—and you might not have cash to pay it if the acquirer's stock is illiquid or restricted.
Double-trigger spreads the risk: you only vest (and owe tax) if you're actually terminated. If you keep your job, you keep vesting on the normal schedule.
Frequently Asked Questions
How do I know if I have single or double-trigger?
Check your equity plan, award agreement, or the merger agreement. HR or your equity administrator can confirm. Don't assume—the terms vary by company and sometimes by grant.
Can I negotiate double-trigger?
Executives sometimes negotiate it. Rank-and-file usually get what the plan says. If you're in a key role and the company is being acquired, it's worth asking.
What if I'm terminated "for cause"?
Termination for cause usually does not trigger double-trigger. You typically forfeit unvested equity. "Cause" is usually defined narrowly (fraud, gross misconduct, etc.). If you're laid off as part of a reduction in force, that's usually "without cause."
Disclaimer: This guide is for educational purposes. It does not constitute legal or tax advice.
Last Updated: March 2026 | Research Team: VestingStrategy