Microsoft today launched a $250,000 contest for researchers who develop defensive security technologies that deal with entire classes of exploits. The total cash awards for Microsoft's "BlueHat Prize" contest easily dwarfs any bug bounty that's been given by rivals. The company announced the contest as this year's Black Hat security conference got under way today in Las Vegas.

More Details here
https://www.microsoft.com/security/bluehatprize/

see rules and regulations
https://www.microsoft.com/security/bluehatprize/rules.aspx