So many variables. First, the software can be sold without an acquihire and is not an uncommon route by traditional enterprises outside of tech (an asset sale)

So many variables. First, the software can be sold without an acquihire and is not an uncommon route by traditional enterprises outside of tech (an asset sale). However, in general even in those cases the acquirer wants at least 1-2 key employees to help them through the transition. I have been though a couple of these with Public companies being the acquirer and am familiar with it. Also, if this was the route the startup would likely be required to pay investors first from the sale, and the chance you or anyone else gets anything is fairly low (so you want/hope for an equity sale not an asset sale). In the end, you aren't a founder so in reality unless the founders are including you on the discussions you won't know for sure what is happening or being discussed. If the founders are good people (but maybe bad business sense), hopefully they will be fighting for their team. You did mention you have a significant equity stake, if it is large enough you may be able to get a seat at the table, depending on if it is options or granted stock and what class of stock it is etc. Also, part of this all depends on how many people are in the company and what the skill set makeup is like. e.g. 6 people total with 4 being devs is different than 6 people with 1 dev when it comes time to be acquired. If the acquirer is a large firm with in place development and product management the chances of you staying in control of the product are slim long term. Short term you might have some say, 3-6 months, but longer term you likely will not. That isn't to say you couldn't, but the odds are against it generally speaking. The smaller the acquirer is, the better the chance you get to stay in a more controlling spot. As for what to do to protect you, don't try to sour the deal, but make sure that you negotiate what is fair to you. I'd stick out the acquihire if the deal was reasonable, you may have to stick around for 12 months or so but for that you may get a small amount of stock or cash. I have not ever done this part, so others here are probably a better source of information.