That doesn't make any sense (i.e., you can stipulate this maintenance of %age, but you are crippling your ability to raise money). Predefined IPO data is simil

That doesn't make any sense (i.e., you can stipulate this maintenance of %age, but you are crippling your ability to raise money). Predefined IPO data is similarly unrealistic, as there are too many external factors. What does make sense is to have a risk conversation with these early people, and be willing to give up enough equity to have that make sense to them. So, if your target is to give them 0.5% "at exit", you're going to be giving them, say, 1-2% initially. And do this in the best way, tax-wise, for them in your jurisdiction.