The Giving Pledge is a commitment by many of the world's wealthiest individuals and families to dedicate the majority of their wealth to giving back. The pledge aims to address the most pressing problems facing society by inviting the wealthiest people in the world to commit to giving the majority of their wealth to philanthropy or charitable causes either during their lifetime or in their wills. The pledge was formed in 2010 by billionaires Bill and Melinda Gates and Warren Buffett, who spoke with their fellow philanthropists as they sought a way to establish a new standard of generosity among the ultra-wealthy. The pledge initially focused on the United States but soon spread across the globe and now includes 170 of the world's wealthiest individuals, couples and families who represent 21 countries. Commitments are made publicly, and each couple or individual provides a statement explaining their decision to make the pledge. In addition to the Gates and Buffett, some of the recognizable people to have made the pledge include Virgin Group founder Richard Branson and his wife, Joan; American filmmaker and entrepreneur George Lucas and his wife, Mellody Hobson; and Facebook cofounder Mark Zuckerberg and his wife, Priscilla Chan.