Another way to think of this problem from a risk perspective is the following.
"I am long equity exposure in some startups. I would like to reduce my exposure. Is there an effective way to hedge my downside risk?"
If the basket of startups is somewhat diverse, then the first question is whether you can find exchange-listed companies or ETFs that operate in, or generate revenue from, the same sector. The diversification will reduce your single-factor exposure, and put options on that exchange-listed instrument will give you some insurance in the case of a correlated crash.
