Quote: Due to our disagreement about the best way to get the most vulnerabilities fixed, Google has withdrawn sponsorship of Pwn2Own. We understand their reasons for doing so: they want to be able to receive the sandbox escape details to improve the security of their product. That is why they launched Pwnium. What we believe they fail to realize is that, for the $60,000 they are offering, it is incredibly unlikely that anyone will participate. For example, a quote from a prior Pwn2Own winner: https://twitter.com/#!/VUPEN: "Google canceled its sponsorship of #pwn2own and launched its own #pwnium. To win, report your sophisticated exploit. We're not interested!".
http://dvlabs.tippingpoint.com/blog/2012/02/29/pwn2own-and-p...