Saying that: “You want to be the pebble in the pond that creates the ripple for change,” Apple CEO Tim Cook told Fortune that he plans to leave all his wealth to charity.

Cook, estimated to be worth about $120 million, said he’ll pay for his 10-year-old nephew’s college before making sure the rest of his money goes to good causes.

Cook follows the lead of billionaire Warren Buffet who encourages the wealthy to give away at least half their worth through the “Giving Pledge.” Buffet’s philanthropy website boasts supporters such as Microsoft’s Bill Gates, Mark Zuckerberg of Facebook and Oracle’s Larry Ellison.

To read the Fortune.com Tim Cook profile, click here.