Forty wealthy families and individuals, including Philadelphia-area philanthropist H.F. "Gerry" Lenfest, have joined Microsoft Corp. cofounder Bill Gates and billionaire investor Warren Buffett in a pledge to give at least half their wealth to charity.

Six weeks after launching a campaign to get other billionaires to donate most of their fortunes, Buffett, the chairman and chief executive officer of Berkshire Hathaway Inc., on Wednesday released the first list of people who have signed what he and Gates call the "giving pledge."

In addition to Lenfest, whose fortune came from cable television, the list included Microsoft cofounder Paul Allen, industrialist Ronald O. Perelman, New York City Mayor Michael R. Bloomberg, eBay Inc. founder Pierre Omidyar, and Turner Television founder Ted Turner.

"We're hoping that America, which is the most generous society on Earth, becomes even more generous over time," Buffett said in a telephone conference announcing the donors. "We hope that not only will that norm move toward even greater philanthropic contributions, but also toward smarter ones."

The pledges come at a time when many philanthropic causes in the United States are barely recovering from a tough two years as individual and corporate donations declined during the credit crunch and recession that followed the 2008 subprime mortgage crisis.

Charitable giving to nonprofits in 2009 fell 3.6 percent from $315 billion to $303.6 billion, according to a report published by the Giving USA Foundation. That was worse than the 2 percent drop to $307.7 billion in 2008.

Buffett decided in 2006 to give 99 percent of his fortune to charity. Then, he was worth about $44 billion. After five years of investment returns while making annual gifts to five foundations, Buffett's fortune totals nearly $46 billion.

Lenfest ran privately held Lenfest Communications Inc. from 1974 to 2000, when he sold it for $1.2 billion in a deal that brought the company under Comcast Corp.'s ownership. By the end of the 1990s, Lenfest Communications, based in Oaks, Montgomery County, had become the Philadelphia area's largest cable operator.

Since the sale, he, his wife, Marguerite, and their three children have been active charitable donors, giving away more than $800 million by mid-2009. Lenfest said then that the family had given away "the bulk of our wealth."

Local beneficiaries of the family include the Barnes Foundation, the Curtis Institute of Music, the Philadelphia Museum of Art, the Independence Seaport Museum, the James A. Michener Art Museum, Swarthmore College, and the Lenfest College Scholarship Program.

Lenfest said Wednesday that his pledge to donate half his fortune to charity was a bit like "closing the barn door after the horse got out."

What remains of his estate will be left to his charitable foundation for further giving after his death and that of his wife.

He said he joined with Buffett and Gates in hopes of encouraging others to be as generous.

Buffett said he, Bill and Melinda Gates, and a few others have made 70 to 80 calls to some of the nation's wealthiest individuals. The people who agreed to the pledge are from 13 states, with the most participants in California and New York.

Among those who haven't signed the pledge, some prefer to keep their philanthropy anonymous, some were not available to talk, and others were not interested, Buffett said.

Many on the list will be asked to call others, and small dinners will be held across the country in coming months to talk about the campaign.

"We're off to a terrific start," Buffett said.

Buffett said he and Bill Gates also will meet with groups of wealthy people in China and India within six months to talk about philanthropy. They hope the idea of generosity will spread, but they have no plans to lead a global campaign, Buffett said.

Gates and Buffett estimate their efforts could generate $600 billion dollars in charitable giving.

For the full list of those who pledge to give at least half their wealth to charity, go to