14 more billionaires just joined Warren Buffett and Bill Gates in pledging to give away most of their money

Fourteen billionaires and billionaire couples have committed to donating most of their fortunes to philanthropic causes, joining Warren Buffett and Bill Gates in signing the Giving Pledge, the organization announced Tuesday.

The new members of the Giving Pledge — a global organization started by Buffett and Bill and Melinda Gates in 2010 to encourage the world's wealthiest to donate a majority of their riches — hail from eight countries and have built a diverse array of businesses.

They include Dean Metropoulos, the private equity titan; Dagmar Dolby, the wife of the audio-systems giant Ray Dolby; Leonard Ainsworth, the Australian founder of a casino-gaming-machines company; and Sir Stelios Haji-Ioannou, the Cypriot founder of easyJet who lives in Monaco.

"Philanthropy is different around the world, but almost every culture has a long-standing tradition of giving back," Melinda Gates, the co-chair of the Bill & Melinda Gates Foundation, said in the Giving Pledge announcement. "Bill and Warren and I are excited to welcome the new, very international group of philanthropists joining the Giving Pledge, and we look forward to learning from their diverse experiences."

Here are the 14 new members and their home countries, according to the announcement:

1. Leonard Ainsworth — Australia

2. Mohammed Dewji — Tanzania

3. Dagmar Dolby — United States

4. Dong Fangjun — People's Republic of China

5. Anne Grete Eidsvig and Kjell Inge Røkke — Norway

6. Sir Stelios Haji-Ioannou — Monaco, Cyprus

7. Nick and Leslie Hanauer — United States

8. Iza and Samo Login — Slovenia

9. Dean and Marianne Metropoulos — United States

10. Terry and Susan Ragon — United States

11. Nat Simons and Laura Baxter-Simons — United States

12. Robert Frederick Smith — United States

13. Harry Stine — United States

14. You Zhonghui — People's Republic of China

The new additions bring this rarefied philanthropy club's total membership to 168 people from 21 countries.

With fortunes of $73.5 billion and $95.5 billion, respectively, Buffett and Bill Gates are among the richest and most generous people on earth. The Gates' lifetime giving now exceeds $32 billion, while Buffett's exceeds $25 billion, according to Forbes.