ALMOST FORTY of America’s richest people have agreed to give over half of their fortunes to charitable causes, in a campaign launched by Warren Buffet with Bill and Melinda Gates.

The Giving Pledge has been signed by many well-known personalities.

The campaign invites the billionaires to publicly pledge the majority of their wealth to philanthropic causes and charitable organizations, either during the person’s lifetime or after their death.

Buffett and the Gates’ are also pledging. Buffet has pledged the majority of his $47bn fortune to the Bill and Melinda Gates Foundation, which  mainly focuses on fighting disease in developing countries.

So who has signed the Giving Pledge? See our top ten below:

Michael Bloomberg

The current mayor of New York City, he was elected for a record third term last year. He is also the founder of news company Bloomberg, and Forbes rates hims as the eighth richest person in the United States, with a personal wealth of $18bn.

He is a long-time philanthropist, having donated millions to the likes of John Hopkins University and to disease research.

William Barron Hilton

Hilton is a hotel heir, former co-chairman of the Hilton Hotels chain, and the original owner of the San Diego Chargers.

On Christmas Day 2007, Hilton announced that he planned to give away 97% of his fortune to a charitable trust that is due to eventually be merged with the Conrad N. Hilton Foundation.

He is one of the sons of Conrad Hilton, the founder of Hilton Hotels, and is grandfather to American socialite Paris Hilton.

Ted Tuner

Robert Edward “Ted” Turner III is an American media mogul and founder the first 24-hour news channel, CNN. Forbes put his wealth at $1.8bn.

He is also the largest landowner in America – with over two million hectares to call his own.

Turner is a well known philanthropist; he has given generously to United Nations causes, depositing a hefty $1bn to the UN in 1998.

George Lucas

Hollywood director George Lucas is most famous for his Star Wars and Indiana Jones films. Forbes put his personal wealth at $3bn.

Lucas is also founder of special effects studio Industrial Light & Magic, which is now the most successful special effects studio in Hollywood.

Barry Diller and Diane von Furstenburg

Fashion designer Diane von Furtsenburg and her media entrepreneur husband Barry Diller have both signed the pledge.

Von Furstenburg is a top designer and Diller is responsible for the creation of Fox Broadcasting Company and USA Broadcasting.

Larry Ellison

Chairman and co-founder of database giant Oracle Corp, Ellsion is the sixth richest person on the planet and the third richest in the United States, according to Forbes. His fortune is an estimated $28bn.

Oracle has recently enlarged after engaging in a large series of acquisitions, buying 57 companies in the last five years alone.

Paul Allen

A university drop out made (very, very) good, Paul Allen co-founded software giant Microsoft with Bill Gates.

The pair founded Microsoft in in 1975 but Allen left in 1983 due to illness. Forbes estimates that he is currently worth $13.5bn.

Bill Gates

The Microsoft mogul is currently worth $53bn according to Forbes, putting him second place in the rich-list rankings.

Although Gates has left Microsoft, he remains the company’s largest single stockholder. In 2000, he established the Bill & Melinda Gates Foundation with his wife, and is known for donating large amounts of money to various causes.

Warren Buffet

Buffet was listed as the richest person in the world in 2009.

One of the most successful investors in the world, he is also widely known for his philanthropic work. Buffet has already promised to give away 99% of his fortune to charitable causes, primarily through the Gates Foundation.