No. 1: Warren Buffett

Amount donated in 2012: about $3.1-billion

Top beneficiaries: Howard G. Buffett Foundation, NoVo Foundation, and the Sherwood Foundation.

Background: He is the chairman of Berkshire Hathaway, an insurance and investment company.

Mr. Buffett, age 82, pledged 12,220,852 shares of Berkshire Hathaway class “B” stock, valued at more than $1-billion, to each of his three children’s foundations. The Howard G. Buffett Foundation gives money to agricultural development, clean-water projects, and programs working to fight poverty. The NoVo Foundation, co-founded by Peter Buffett and his wife, Jennifer, seeks to improve the well-being of girls and women globally and supports economic and education programs. The Sherwood Foundation, founded by daughter Susan Buffett, supports social-justice and early-childhood education.

This pledge follows a 2006 promise to give each foundation about $1-billion, which Mr. Buffett has been steadily paying off each year.

He will begin paying down this latest commitment later this year.

In addition, Mr. Buffett gave stock worth close to $1-million to a charity in 2012 that he declined to name and 10 shares of stock, currently valued at about $12,000 apiece, to each of 15 elementary-school students who won an educational contest sponsored by Mr. Buffett called the “Grow Your Own Business Challenge.” The contest is associated with “The Secret Millionaires Club,” an animated television show that features Mr. Buffet and seeks to teach children about business and personal finance.