Pwnium is the annual Hacking Contest where Google invites coders from around the world to find security holes in Google Chrome. Google has announced its 4thhosted at the Canadian Security conference in March, offering more than $2.7 million in potential rewards for hacking Chrome OS-running ARM and Intel Chromebooks. Google will also pay USD 150,000 for providing an exploit, able to persistently compromise an HP or Acer Chromebook, i.e. hacking the device to retain control even after a reboot.
Source: https://thehackernews.com/2014/01/google-announces-27-million-reward-for.html