More billionaires showing their benevolence is a business trend we can get behind.

Nine new wealthy donors and their families signed on to the Giving Pledge on Tuesday, promising to donate at least half their wealth to charity as part of a non-binding moral contract started by Warren Buffett and Bill and Melinda Gates in 2010.

The new group includes Sara Blakely, the founder of Spanx, who is the first female billionaire to join the pledge and also the youngest self-made woman to reach billionaire status at age 41, according to Forbes.

Blakely said in her Giving Pledge letter that she wishes to further her philanthropic work in empowering underserved women.

“Since I was a little girl I have always known I would help women. In my wildest dreams, I never thought I would have started with their butts…I have so much gratitude for being a woman in America. I never lose sight that I was born in the right country at the right time. And I never lose sight of the fact that there are millions of women around the world who are not dealt with the same deck of cards upon their birth.”

Blakely and Spanx, a private company of which she owns 100 percent, have donated $17.5 million to charities that empower women and girls, thanks in part to another Giving Pledge member. After appearing on Virgin Group founder Richard Branson’s reality show “Rebel Billionaire,” which aired on Fox in 2004, the mogul gave her $750,000 to start a foundation, Forbes reported.

Earlier this year, Branson paved the way as one of the first non-U.S. billionaires to sign on to the pledge.

Past notable Giving Pledge signatories include Facebook founder Mark Zuckerberg, New York Mayor Michael Bloomberg and Netflix CEO Reed Hastings.

See the full Giving Pledge list here.

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  • George Lucas

    Hollywood director George Lucas is passionate about education. He has worked to foster positive growth in the education sector through, <a href=”http://www.edutopia.org/” target=”_hplink”>Edutopia</a>, the George Lucas Education Foundation. Lucas plans to donate the majority of his fortune to this end.

  • Paul G. Allen

    Microsoft co-founder Paul Allen has supported his namesake, the <a href=”http://www.pgafoundations.com/” target=”_hplink”>Paul G. Allen Family Foundation</a>, for more than 20 years, as well as helped advance nonprofit scientific research through the Allen Institute for Brain Science. Allen has already given hundreds of millions of dollars to charity through his foundation, and has expressed his commitment to give the <a href=”http://www.huffingtonpost.com/2010/07/15/paul-allens-charity-promi_n_648142.html” target=”_hplink”>majority of his fortune</a> after his death.

  • Barron Hilton

    Barron Hilton (left) plans to immediately pledge over $1 billion to the <a href=”http://www.hiltonfoundation.org/” target=”_hplink”>Conrad N. Hilton Foundation</a>, which provides funds for nonprofits addressing a variety of issues, including homelessness, access to clean water and disaster relief. Hilton also plans to follow an example set for him by his father, donating the remaining 97 percent of his wealth in the future.

  • Ted Turner

    In 1998, media mogul Ted Turner donated $1 billion to start the <a href=”http://www.unfoundation.org/about-unf/” target=”_hplink”>United Nations Foundation</a>. Turner plans to continue giving, saying that his fortune should be almost completely distributed to charity at the time of his death.

  • Michael Bloomberg

    Mayor of New York City Michael R. Bloomberg plans to give away the majority of his wealth during his lifetime, explaining that it is a better way to ensure a <a href=”http://givingpledge.org/#michael+r.+_bloomberg” target=”_hplink”>better future for his children</a> than leaving them to inherit his fortune. According to Bloomberg, his <a href=”http://www.mikebloomberg.com/index.cfm?objectid=B96D19BD-C29C-7CA2-F72C5EDC3BEDFA6A” target=”_hplink”>foundation</a> is currently working to find ways to prevent early deaths caused by tobacco use and traffic accidents.

  • David Rockefeller

    The Rockefeller family has historically been involved in philanthropic efforts supporting University of Chicago, <a href=”http://www.rockefeller.edu/” target=”_hplink”>The Rockefeller University</a>, the Museum of Modern Art, and the <a href=”http://www.rbf.org/” target=”_hplink”>Rockefeller Brothers Fund</a>. David Rockfeller, the current heir, has pledged the majority of his wealth to charity.

  • Jon and Karen Huntsman

    After losing his mother to cancer, businessman Jon Huntsman felt called to found the <a href=”http://www.hci.utah.edu/” target=”_hplink”>Huntsman Cancer Institute</a> and use his fortune to find a cure for cancer. Huntsman plans to leave his entire estate to his foundation and other cancer-related charities.

  • Alfred Mann

    In 1985, businessman Alfred Mann founded the <a href=”http://www.aemf.org/” target=”_hplink”>Alfred Mann Foundation</a> to fund scientific research in the field of medicine. Mann has joined the ranks of the ‘Giving Pledge,’ planning to commit 90 percent of his estate to his foundation and other causes.

  • Eli and Edythe Broad

    Billionaire businessman and real estate mogul Eli Broad and his wife, Edythe, have pledged to give away 75 percent of their fortune within their lifetimes. The <a href=”http://www.broadfoundation.org/” target=”_hplink”>Broad Foundation</a> supports arts organizations, funds advancements in medical science and advocates for education reform.