Not patio11 but you can still evaluate something like net preset value by doing discount to the eventual liquidity event. In reality this is complicated as you need to assign probabilities to (1) when liquidity event can occur (2) real value of your equity at the event (3) discount rate.
While estimating probability distributions is probably beyond what one can do without detailed inside knowledge (and even then), it's useful to think of a number of stories, eg: target_co will ipo in 3 years at 2x last raised value, target_co will ipo in 5 year at last raise, target_co will be acquired at 0.1x last raise in 8 years (what is the overhang?); let's say all at equal probabilities. For discount rate you can think of alternative places where you could work (eg. alternative_public_co will grow at -10, +20, +30% yoy with equal probability) + time value of not being able to liquidate (let's say another 10%).
This will give you some range of numbers to consider.
While estimating probability distributions is probably beyond what one can do without detailed inside knowledge (and even then), it's useful to think of a number of stories, eg: target_co will ipo in 3 years at 2x last raised value, target_co will ipo in 5 year at last raise, target_co will be acquired at 0.1x last raise in 8 years (what is the overhang?); let's say all at equal probabilities. For discount rate you can think of alternative places where you could work (eg. alternative_public_co will grow at -10, +20, +30% yoy with equal probability) + time value of not being able to liquidate (let's say another 10%).
This will give you some range of numbers to consider.