Carl Icahn speaking at Delivering Alpha in New York on Sept. 13, 2016.Billionaire investor Carl Icahn took a significant stake in auto-service chain Monro, becoming the largest single shareholder and marking his latest move in the automotive sector.Icahn disclosed ownership of 4,439,914 shares, representing a 14.8% stake in Monro, according to a new regulatory filing. The filing showed the shares were acquired by Icahn's investment entities. It wasn't clear whether he plans to push for changes at Monro.Icah ...