Let sleeping dogs lie, don’t poke the bear, and never, ever antagonise your company’s billionaire major shareholder – especially if he’s already voiced a desire to replace you. Klaus Kleinfeld should have borne this final point in mind when he penned a letter to Paul Singer earlier this month. The correspondence gave Singer, the man behind hedge fund Elliott Management, the ammunition needed to blast Kleinfeld out of Arconic Inc, parent company of Alcoa Wheels.