Berkshire was Exxon’s sixth-largest shareholder before liquidating its position, and the stake counted as the eighth-largest (3.7%) in the portfolio run by Buffett and lieutenants Todd Combs and Ted Weschler. The firm also exited its remainingConocoPhillips COP -0.59% position, which it had been cutting back for the past several years and amounted to just 471,994 by Sept. 30, less than 0.1% of the Berkshire stock portfolio.