[dspillett]

As much as every acquirer will say about "investing in the team, not just buying the product", aside sometimes for a couple of key people adding the IP to their portfolio and integrating it with their existing offering (or keeping it down if it competes with their existing offering) is their main interest.

Employee retention defaults to being managed by notice periods and other contract conditions being inherited from the acquired entity, after that the new owner and the employees need to negotiate (unless "keep as you are" is what both parties want at this time). If you are on one month notice or less start looking around just in case, if you are on six months you have plenty of time to plan if things do look like working in a way you are not happy with.

Sometimes, again for key people, the negotiations happen as part of the main dealing before the purchase (after purchase we'll X if you Y and not Z) by proxy (the acquirer can't directly dictate anything at this point, but they can say "we won't buy unless Y+Z is agreed, we promise X in return for Y+Z if we do purchase" to the prospective purchasee and they then officially negotiate with the employees).

It is about the IP. If you are directly and visibly important to the IP then you are important to the purchaser and have a good negotiating position. The buyer knows this and it will form part of their negotiation plan (to make sure they have a viable business after purchase) so unless they are buying to silence competition they are unlikely to do anything too unfriendly to the existing staff (but make damn sure you raise any concerns you may have if you get chance before anything is agreed).