Luca Cordero di Montezemolo will step down as chairman of Ferrari as of Oct. 13 and will be replaced by Sergio Marchionne, who also serves as the chief executive of parent group Fiat The departure of Montezemolo, announced by Fiat on Wednesday, was widely expected after escalating clashes between the two executives over strategy and the role of the luxury sports car business within the Fiat group. Fiat shares were up 2.4 percent by 0721 GMT , against a 0.1 percent fall for Milan's blue-chip index .