What just happened? MacKenzie Bezos, now the world's third richest woman, has pledged to give away at least half of her fortune to charity. In her Giving Pledge letter, MacKenzie said she has a disproportionate amount of money to share and "will keep at it until the safe is empty."

MacKenzie Bezos on Tuesday announced intentions to give away at least half of her fortune to charity, joining more than 200 of the world's wealthiest individuals and couples that have vowed to do the same through the Giving Pledge.

The Giving Pledge is a charitable organization founded by Bill Gates and Warren Buffett in 2010 that encourages wealthy individuals and couples to contribute at least half of their net worth to philanthropic causes, either during their lifetime or when they die.

MacKenzie's divorce from Amazon founder Jeff Bezos was finalized last month. The two were married in 1993, a year before Amazon was incorporated. As part of the divorce, Jeff kept 75 percent of their joint Amazon stock as well as their interests in Blue Origin and The Washington Post.

Even still, MacKenzie's stake in Amazon is estimated to be worth north of $35 billion, making her the third richest woman and the 22nd richest person in the world.

Bloomberg has Jeff Bezos listed as the world's richest person with a total net worth of around $114 billion. To date, he has not signed the Giving Pledge put praised MacKenzie's decision earlier today on Twitter.

Image credit: Elena Sibert