Our 2017 annual letter is addressed to our dear friend Warren Buffett, who in 2006 donated the bulk of his fortune to our foundation to fight disease and reduce inequity. A few months ago, Warren asked us to reflect on what impact his gift has had on the world.
Dear Warren,

Ten years ago, when we first got word of your gift to the foundation, we were speechless. It was the biggest single gift anyone ever gave anybody for anything. We knew we owed you a fantastic return on your investment. Of course, philanthropy isn’t like business. We don’t have sales and profits to show you. There’s no share price to report. But there are numbers we watch closely to guide our work and measure our progress. Our goals are shared by many other organizations working to save and improve lives. We’re all in this together. So most of the numbers we look at don’t focus just on how we as a foundation are doing, but on how the world is doing—and how we see our role.