To echo the other commentators, another way to think about this is: a seed stage company like this is worth ~$0 if the investor owned 100%. But it's worth $X mi

To echo the other commentators, another way to think about this is: a seed stage company like this is worth ~$0 if the investor owned 100%. But it's worth $X million, if the investor only owns 20%; the "team commitment" factor being a multiplier on the total valuation that has an inverse relationship with the investor's ownership percentage.