SHAREHOLDERS in Rio Tinto and SABMiller should be concerned about sharing a chairman next year, a UK adviser to investors with £1.5 trillion (R27 trillion) in assets said yesterday. SABMiller said yesterday that Jan du Plessis would replace John Manser as chairman in July next year. Du Plessis, who has chaired Rio Tinto since 2009, would become an independent non-executive director at SABMiller on September 1. “Chairing a company like Rio Tinto would be very close to being a full-time job, if it is to be done effectively,” Andrew Whiley, a spokesman at Pensions & Investment Research Consultants, said. “Are SABMiller really saying that out of all of the talented men and women that could chair their company this is the best candidate available?” – Bloomberg