Mark Zuckerberg

Lifetime donations: $1.6 billion
Net worth: $40.7 billion
Generosity Index: 4%
Facebook founder and CEO Mark Zuckerberg is one of the youngest self-made billionaires in the world. The social-media mogul has signed the Giving Pledge and promises to donate at least half of his wealth in his lifetime.
Last year, Zuckerberg and his wife Priscilla famously donated $25 million in the fight against Ebola. Through the Silicon Valley Community Foundation, Zuckerberg gave $75 million to San Francisco General Hospital.
They're also focused on education: The pair gave $120 million to improve Bay Area schools, and before that, donated $100 million worth of Facebook shares to a New Jersey public-school system.
Source: Wealth-X

Paul Allen

Lifetime donations: $2 billion
Net worth: $17.3 billion
Generosity Index: 12%
Paul Allen, cofounder of Microsoft, now serves as the chairman of Vulcan, his private-investment company.
As chairman of the Paul G. Allen Family Foundation, he's given millions to global-health causes, including $5 million to Seattle BioMed, $4 million to Global FinPrint, a conservation project focused on the preservation of sharks worldwide, and $7 million in grants to Alzheimer's research.
Source: Wealth-X

Michael Bloomberg

Lifetime donations: $3 billion
Net worth: $37.7 billion
Generosity Index: 8%
Michael Bloomberg is the founder and CEO of Bloomberg media company and founder of the Bloomberg Foundation, which gives primarily to educational, healthcare, and environmental causes. Recipients of the foundation's donations include John Hopkins University, World Lung Foundation, World Health Organization, Sierra Club Foundation, and John Hopkins Bloomberg School of Public Health.
Most recently, Bloomberg launched a $42 million "What Works Cities" initiative aimed at helping 100 mid-sized cities to make better use of data and evidence through his philanthropic arm, Bloomberg Philanthropies.
Source: Wealth-X

George Kaiser

Lifetime donations: $3.3 billion
Net worth: $9.3 billion
Generosity Index: 35%
George Kaiser, chairman of BOK Financial Corporation, also founded the George Kaiser Family Foundation, which gives to educational, health, religious, social, and community-development-related causes, including the Tulsa Community College Foundation, Oklahoma City Educare, National Energy Policy Institute, the Tulsa Community Foundation and the University of Tulsa.
In 2010, Kaiser joined the Giving Pledge, vowing to donate half of his fortune to charity.
Source: Wealth-X

Eli Broad

Lifetime donations: $3.3 billion
Net worth: $7.3 billion
Generosity Index: 45%
Through The Broad Foundation, KB Home cofounder and former SunAmerica CEO Eli Broad invests in public education, science, and the arts.
The organization operates as two entities, The Eli and Edythe Broad Foundation and The Broad Art Foundation, both of which aim to improve communities and advance entrepreneurship.
A resident of California, Broad gives back to his home state — and the arts — through donations to the Museum of Contemporary Art, Los Angeles and the Los Angeles County Museum of Art.
Source: Wealth-X

Carlos Slim Helú

Lifetime donations: $4 billion
Net worth: $27.3 billion
Generosity Index: 15%
One of the richest self-made billionaires in the world and the chairman of Grupo Carso, Carlos Slim Helú's primary philanthropic efforts occur through his Fundación Carlos Slim Helú.
The foundation has invested $100 million in the World Wildlife Fund toward efforts to conserve Mexico's natural environment, and in 2012, it gave $3 million to help provide internet to Latino families living in the US, in addition to many other donations to international organizations.
Slim Helú also serves as chairman of the Telmex Foundation, which strives to improve the quality of life in Mexico, his home country.
Source: Wealth-X

Gordon Moore

Lifetime donations: $5 billion
Net worth: $6.5 billion
Generosity Index: 77%
Gordon Moore cofounded Intel in 1968, but these days he is focused on philanthropy. He retired from his corporate positions in 2006, and currently runs the Gordon and Betty Moore Foundation with his wife.
The foundation aims to make an impact in environmental conservation, patient care, science, and the San Francisco community, and has wide-spanning programs that include everything from the Marine Conservation Initiative to the Thirty Meter Telescope.
Source: Wealth-X