Berkshire Hathaway Letters to Shareholders: 1965-2024

by Warren Buffett

We face another obstacle: In a finite world, high growth rates must self-destruct. If the base from which the growth is taking place is tiny, this law may not operate for a time. But when the base balloons, the party ends: A high growth rate eventually forges its own anchor. Carl Sagan has entertainingly described this phenomenon, musing about the destiny of bacteria that reproduce by dividing into two every 15 minutes. Says Sagan: “That means four doublings an hour, and 96 doublings a day. Although a bacterium weighs only about a trillionth of a gram, its descendants, after a day of wild asexual abandon, will collectively weigh as much as a mountain…in two days, more than the sun—and before very long, everything in the universe will be made of bacteria.” Not to worry, says Sagan: Some obstacle always impedes this kind of exponential growth. “The bugs run out of food, or they poison each other, or they are shy about reproducing in public.”