You know, I originally had a hard answer and edited it away because I think OP is ambiguous. >for $150,000 you could have bought 10% of Airbnb. Does that mean

You know, I originally had a hard answer and edited it away because I think OP is ambiguous. >for $150,000 you could have bought 10% of Airbnb. Does that mean for $150K I can buy as many shares as constitute 10% of the current outstanding number? Or that after I pay $150K, I will own 10%? Since new shares are issued, in the former case I end up with 9.0909...% (1/11th) of the company. That gives us a post-money valuation of... $1.65M! (and $1.5M pre-money) But in the more probable reading of the phrase, I own 10% of the post-money $1.5M company, giving us $1.35M pre-money. So, your choice. Someone more in the VC loop might be able to say that the phrasing definitely means one or the other; I've just got the math.