After a remarkable 60 years at Fortune, writer and reporter Carol Loomis is ready to retire from her day job at the age of 85.
Managing Editor Andy Serwer made the announcement in an online story in which he called her "arguably the greatest business journalist of our time."
Serwer quotes Buffett as saying, "Carol is one of the few people who is smarter at the end of every day than she was at the beginning of it. She has a reverence for facts, and then she makes them understandable and fun to read. You always wish her stories were longer. That's the real sign of a great writer."
In a 2009 interview with CNBC, Buffett called Loomis a "tough editor" and she agreed. But, she said, the content of Buffett's letters is "all his."
"I help out a little bit on the presentation, but it's Warren who writes the annual report. There's no question about that."
Loomis has broken some of Buffett's biggest stories, including his 2006 decision to give away almost all of his money to the Bill & Melinda Gates Foundation.
In late 2012, Buffett made several media appearances with Loomis, including one of CNBC, to help promote her book, Tap Dancing to Work: Warren Buffett on Practically Everything, 1966-2012. It's a collection of Fortune's articles about Buffett.
In his story, Serwer says Loomis will "continue writing some for Fortune in retirement."
It would be no surprise if she also takes some time to keep helping Buffett with his annual letter.
—By CNBC's Alex Crippen. Follow him on Twitter: @alexcrippen