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The billionaire founder of social network Facebook Inc. has agreed to give the majority of his wealth to charity, part of a broader group of rich entrepreneurs committing to philanthropy earlier in their lives.

Mark Zuckerberg has signed onto the "Giving Pledge," which asks its signatories to commit publicly to give away the majority of their wealth.

The 26-year-old is one of 16 billionaires new to the pledge, which now totals more than 50 donors. New names include AOL co-founder Steve Case, investor Carl Icahn and former junk-bond king Michael Milken.

They join existing pledges made by wealthy individuals and families including Oracle Corp. founder Larry Ellison, film director George Lucas and New York Mayor Michael Bloomberg.

The Giving Pledge is an effort organized by software mogul Bill Gates and investor Warren Buffett to persuade the world's rich to boost their giving.

"I view this as a call to others who might in their thirties or forties use some of their creativity to get involved in philanthropy earlier in life," Milken, 64, said of the pledge.

Those pledging are part of a broader shift in philanthropy, in which successful business people—often entrepreneurs—are giving more of their money to charity far earlier than their predecessors. It was a trend that was helped along by Gates, who started his foundation while still leading Microsoft Corp.

Case, 52, and his wife Jean Case, 50, said they signed the pledge because they hoped it would help philanthropists learn from each other. "It is less about what size of a check that you write and more about the outcome," Case said.

Continue reading at The Wall Street Journal