For several years now, the board has had someone in mind who would step in to run the company if Buffett was suddenly unable to do the job, and that someone doesn't know he's waiting in the wings. The board also has two or three other people in mind if needed.
While Buffett and his doctors are confident the cancer is treatable and not life threatening, the development is once again fueling the long-running guessing game on who will be running Berkshire Hathaway in the (Buffett hopes) far future.
Here are some of the leading candidates.
First, it's almost certainly someone who is already running a Berkshire subsidiary.
In his annual letter to shareholders in February, Buffett wrote the Berkshire board is enthusiastic about his successor, "an individual to whom they have had a great deal of exposure, and whose managerial and human qualities they admire."
A few days later, in a live CNBC interview, Buffett said, "The person who's going to become CEO of Berkshire is probably a CEO of some operation within Berkshire Hathaway."
Our leading candidate: Greg Abel, chairman and CEO of Berkshire's MidAmerican Energy.
Quick, our Buffett expert, her producer Lacy O'Toole, and I all have his name at the top of our lists. Abel's been working for MidAmerican for many years and became its CEO in 2008. Like other managers, he has been singled out for praise in several of Buffett's annual letters.
Of course, Buffett's insurance chief, Ajit Jain,also gets glowing praise from Buffett and he has long been seen as one of the leading contenders. CNBC's "Squawk Box" co-anchor, Andrew Ross Sorkin, also a long-time Buffett-watcher, tells me he's not sure who the successor is, but he thinks it should be Jain, because he's the smartest person in the group. Andrew thinks Ajit is "closest in mindset" to Buffett, but he's more of an insurance guru than an operating manager.
Another possibility from Berkshire's insurance side is Tony Nicely. He runs the GEICO auto insurance business and has also been lavished with praise by Buffett.
Burlington Northern Santa Fe CEO Matthew Rose and Lubrizol CEO James Hambrick are also possibilities, but they're relative newcomers to the Berkshire family. Burlington Northern was acquiredin 2010 and Buffett bought Lubrizol in 2011.
In that February live interview with us, Buffett said the person the board has in mind now is the same person they had in mind at least five years ago.
That means, and Buffett has confirmed, that former MidAmerican Chairman David Sokol was never the name in the board's envelope — even before he left Berkshire after it was revealed he had bought Lubrizol shares while he knew Berkshire might acquire the company.
That underlines just how difficult this guessing game has become, because Sokol was widely seen as the leading CEO contender until he resigned in disgrace.
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