Kraft Heinz is breaking up. Merging the food giants was a 'rare' misfire by Warren Buffett.

Warren Buffett's dealmaking made him a legend, but the breakup of Kraft Heinz marks one of his few missteps, the investor's close followers say. Buffett's Berkshire Hathaway conglomerate partnered with Brazilian private equity firm 3G Capital to acquire Heinz for around $23 billion in 2013. Two years later, they teamed up again to merge Heinz with Kraft in a $40 billion deal.Buffett, a fast-food aficionado, called it "my kind of transaction," adding that the combined company could "supply you Heinz ketchup ...