people ask about equity acceleration a lot when they get laid off. thought i'd write up what i actually learned going through this at a late-stage startup two years ago.
the two types:
single trigger - accelerates some or all of your unvested shares automatically on a change-of-control (acquisition, merger). has nothing to do with you being laid off in a regular RIF. most employees have this if they have any acceleration at all.
double trigger - accelerates if BOTH a change-of-control happens AND you're terminated (or resign for good reason) within some window (usually 12-18 months post-close). this is the one that actually protects you in a layoff-post-acquisition scenario.
what you almost certainly do NOT have:
a clause that accelerates vesting just because you were laid off in a normal reduction-in-force, with no acquisition involved. that's not standard. if you think you have this, read your grant agreement carefully. most people misremember what they signed.
what you might be able to negotiate:
if your layoff is happening in the middle of a quarter, you may be able to push for a few extra weeks of employment to hit your next cliff date. i did this. asked HR if my last day could be pushed 3 weeks to let me hit the quarterly vest. they said yes without much pushback. worth asking. the cliff date is in your grant agreement.
also check if the company will extend your post-termination exercise window for options. standard is 90 days. some companies will extend to a year or longer in a layoff scenario, especially if your options are deep in the money. this is a specific ask, not an automatic thing.
your documents to locate immediately: equity grant notice, equity plan document (the full thing, not the summary), and the separation agreement before you sign it. the last one may include equity-specific terms that override your defaults.