NEW YORK: Bill Gates and Warren Buffett think fellow US billionaires should donate most of their vast fortunes to charity -- and they revealed Wednesday that 40 are set to do just that.

"Forty of the wealthiest families and individuals in the United States have committed to returning the majority of their wealth to charitable causes," said a statement released by www.givingpledge.org.

The Giving Pledge, announced just six weeks ago, is the brainchild of Microsoft mogul Gates and investment guru Buffett who want to convince the richest people in the country to give 50 percent or more of their fortune to charity.

As of Wednesday, the group includes CNN founder Ted Turner, New York Mayor Michael Bloomberg, Oracle co-founder Larry Ellison and Hollywood director George Lucas, as well as Buffett and Gates.

Buffett said they simply started working their way through Fortune magazine`s list of 400 US billionaires, who between them have an estimated net worth of 1.2 trillion dollars.

"We probably called somewhere between 70 and 80 people on the Forbes list. It was a very soft sell, but 40 signed up," the chief executive of investment firm Berkshire Hathaway told reporters in a conference call. "We`ve made a terrific start."

The idea is to squeeze morally-, not legally-binding pledges from the super wealthy.

There`ll be no group decisions on how money is spent or when. Instead, club members are to set an example by funding philanthropic pet projects, such as health, education and arts -- and preferably sooner rather later.

"You don`t have to wait to die to give it away," said Bloomberg, a media entrepreneur and major philanthropist whose worth is estimated by Forbes at 18 billion dollars. "It never made a lot of sense to me why you`d want to change the world for better and not be around to see it."

Almost all on the list are self-made, such as Bloomberg, and are worth about a billion dollars, or far more. A few represent longer-established fortunes, including David Rockefeller.

They are not talking about taking vows of poverty. Bloomberg said he would ensure that his children were never destitute.

But he still has more than he can ever need. "You can`t spend it if you have over a certain amount," he explained.

US billionaires have been out of favor with the public and politicians since the 2008 financial collapse. The pledge scheme might burnish their image.

"Business people are pretty widely mistrusted and seen as overwhelmingly self-interested," conceded investment banker and newly signed-up pledge member Tom Steyer during the conference call.

"Warren and Bill Gates` point is an emphatically different one."

Apart from good PR, the scheme raises the prospect of eye-popping amounts of money flowing to charity.

If Gates and Buffett secured pledges of half the wealth of the 400 richest in the country, that would total more than 600 billion dollars, according to Forbes magazine estimates.

Gates alone is the second richest man in the world according to Forbes, with some 53 billion dollars, which places him narrowly behind Mexican telecoms tycoon Carlos Slim, with 53.5 billion.

Buffett, the second richest American, already announced in 2006 that he wanted gradually to give away all of his fortune estimated by Forbes at 47 billion dollars.

Rumors of the unprecedented drive first leaked in May 2009 when it emerged that Gates and Buffett had organized a secretive dinner for billionaires in New York City.

Wednesday`s list featured some notable absences, including investor George Soros.

Buffett said that many had not been called yet and that others were simply unavailable. He would not say who had refused.

"I won`t name any specific names," he said, adding that he expected the project to grow over the next year.

"You know, we don`t give up on them. Every saint has a past, every sinner has a future."

BDST: 09:29 HRS, August 05, 2010