By Caroline Preston

The country’s three best-known philanthropists — Bill and Melinda Gates and Warren Buffett — are embarking on a massive effort to encourage other rich people to give, a move that, if successful, could fundamentally rewrite how the megarich approach charity.

The trio will be trying to prod their rich peers — other billionaires, in particular — to pledge 50 percent of their fortunes to charity, Fortunereports in a detailed article on the effort.

That would have a huge impact on how much money currently flows to nonprofit groups. If individuals on the Forbes 400 list pledged half of their net worth to charity, that would amount to $600-billion, Fortune says.

Serious discussions of the plan Fortune is calling “the biggest fund-raising drive in history” began last summer at a gathering of some of the country’s most prominent donors. Mr. Buffett and the Gateses asked David Rockefeller to host the meeting, which also brought together Oprah, Ted Turner, Eli and Edythe Broad, and Michael R. Bloomberg, among other philanthropy A-listers.

News of the event was leaked to the media, but more dinners, held in secrecy, followed, saysFortune.

With the philanthropists’ plan revealed today, the question now is how many rich people will respond to this ultimate fund-raising solicitation. According to Fortune, the Gateses and Mr. Buffett will soon be sending e-mails and making calls to other billionaires deemed most likely to give, with solicitation efforts by other major philanthropists to follow. No doubt every charity fund raiser out there will be wishing Mr. and Ms. Gates and Mr. Buffett lots of luck with those “asks.”

The Chronicle will post more details about this effort throughout the day, but let us know what you think by adding your comment below.

To learn more about America’s most-generous donors, see The Chronicle’s Philanthropy 50 ranking. Last year, only 17 of the people on the Forbes 400 gave enough to be included on this list.