Often when people think about money they think of having it, not giving most of it away. But for these three millionaires, who were once billionaires, giving is second nature.
With the help of Wealth-X, which does research and valuations on ultra-high-net worth people, we recently published a list of the 20 most generous people in the world. Wealth-X provided us with each philanthropist's amount of lifetime donations and net worth, as well as each person's "Generosity Index."
The Generosity Index shows the amount of money they have donated in relation to their net worth. Out of the 20 people, three donated more money than they currently have, making their generosity indexes greater than 100%.
In total, Jon Huntsman Sr., Suleiman bin Abdul Aziz Al Rajhi, and Charles Francis Feeney have collectively given $13.2 billion to causes around the world. The common conviction among them: True satisfaction comes from seeing your private wealth in the hearts and hands of the public.
Scroll on to see why these philanthropists are donating a majority of their fortunes:
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Charles Francis Feeney has donated $6.3 billion.

Known to some as the "James Bond of philanthropy," Chuck Feeney, the creator of duty-free shopping, is on a mission to give away his entire fortune. In fact, Feeney is working overtime to donate most of his riches by the end of 2016. Today, the 84-year-old has an estimated net worth of $1.5 million, which will allow him to live comfortably in his final years.
Feeney is the founder of Atlantic Philanthropies, an organization established in 1984 that's dedicated to aiding important causes across the globe. Within two years of founding Atlantic, Feeney had donated the majority of his personal wealth to the organization to fund projects related to education, science, healthcare, and civil rights.
"I had one idea that never changed in my mind — that you should use your wealth to help people," Feeney said in a 2007 biography. At the end of last year, Feeney made one of his final donations through Atlantic Philanthropies to Northern Ireland. The $28 million grant will be used to promote shared education for Protestant and Catholic children, parenting programs, and improvements to dementia care.
After nearly three decades and over $6 billion of giving, Feeney has become one of the most generous people on the planet: "I want the last check I write to bounce."
Sulaiman bin Abdul Aziz Al Rajhi has donated $5.7 billion.

In 1957, Sulaiman bin Abdul Aziz Al Rajhi cofounded Al Rajhi Bank with his three brothers. It grew into one of the world's largest Islamic banks and earned Al Rajhi a 10-digit net worth.
After shifting his focus to philanthropy and making the decision to give half of his riches to his children and half to charity, he's now worth just $590 million, putting his Generosity Index at 966%.
The 95-year-old is the founder of Sulaiman Bin Abdul Aziz Rajhi Charitable Foundation, which supports educational, religious, health, and social causes. The foundation has donated to the Arab Institute for Arabic Language, National Guard Health Affairs, and the Sheikh Sulaiman bin Abdul Aziz Al Rajhi Mosque in Riyadh, Saudi Arabia.
The Saudi Arabian businessman revealed in an interview that he's no stranger to poverty, having been penniless on two separate occasions in his life. He appreciates his wealth and knows others will benefit too. "In the past, I never gave money to my children when they were young in return for nothing. When one of them approached me to give them cash, I asked them to do some work in exchange for it," he said.
Jon Huntsman Sr. has donated $1.2 billion.

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