To my knowledge yes, but it was reduced in the last batch.
http://thenextweb.com/insider/2012/11/26/y-combinator-reduci...
http://thenextweb.com/insider/2012/11/26/y-combinator-reduci...
http://www.thenewamerican.com/usnews/politics/item/3286-face...
To clarify, Yuri Milner was not an investor in the company referenced.