Warren Buffett's annual letter to Berkshire Hathaway shareholders is considered a must-read for investors.
Buffett aims to make the letter accessible as well as informative, and he's careful not to include too much jargon. To keep it readable, he writes the letter as if he's talking to his two sisters.
"It's 'Dear Doris and Bertie' at the start and then I take that off at the end," Buffett told CNBC's Becky Quick in an exclusive interview on "Squawk Box" on Monday.
That's because, for Doris and Bertie, "Berkshire is pretty much their whole investment." And although they're smart, Buffett says, his sisters are "not active in business, so they're not reading about it every day. I pretend that they've been away for a year and I'm reporting to them on their investment."