Warren Buffett has spent decades urging investors to separate a company’s underlying economics from the market’s shifting enthusiasm. In Berkshire Hathaway’s (BRK.B) (BRK.A) 1993 shareholder letter, the CEO revisited a theme that runs through much of his writing: in the short term, stock prices can depart sharply from the progress of the businesses they represent. That performance gap, he suggested, can persist long enough to tempt investors into confusing momentum with durability — even though it rarely b ...