#6 Marc Benioff: Fetal surgery

This chairman and CEO of salesforce.com is famous for his 1-1-1 philanthropic model in which companies dedicate a percentage of profits, equity, and employee time to nonprofit work.

Benioff, who hails from San Francisco has lot of pet projects around this city. But he's best known for his $100 million donation for the 180-bed UCSF Benioff Children's Hospital. He was drawn to UCSF because of its "pioneering work with fetal surgery," he said in an interview with Forbes.

#5 Dustin Moskovitz: Malaria and parasite worms

This co-founder of Facebook, who left the company to co-found Asana, wants to solve poverty-related diseases. His foundation, Good Ventures, gives money to causes recommended by GiveWell, a nonprofit run by Moskovitz's girlfriend, former Wall Street Journal reporter Cari Tuna. Good Ventures donated $500,000 to fight malaria and another $250,000 to fight schistosomiasis, a disease caused by parasitic worms.

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