Angel investor and entrepreneur Paul Graham has revealed some numbers about Airbnb and Dropbox. Graham gained equity stake in both companies through Y Combinator. Graham pointed out that most of the returns in startup investing comes from several winners.
The total value of the companies that Y Combinator has funded is around $10 billion. Two companies Airbnb and Dropbox are about three-quarters of it. About a year ago Dropbox was worth around $4 billion and Airbnb was worth around $1.3 billion.
This is a 42% increase in their valuations and the two companies have not had a major round since then. The reason for the increase in valuation could be possibly due to secondary markets or 409a valuations that companies must do before issuing stock options to employees according to BusinessInsider.