As of August 26, 2015:
Number of YC companies worth more than $1 billion: 8 [1]
Number of YC companies worth more than $100 million: >40
https://blog.ycombinator.com/yc-stats/
As of August 26, 2015:
Number of YC companies worth more than $1 billion: 8 [1]
Number of YC companies worth more than $100 million: >40
https://blog.ycombinator.com/yc-stats/