Turin, May 30 - Fiat Chairman John Elkann on Thursday said Sergio Marchionne should stay on as the carmaker's CEO beyond 2015 and that the planned merger between Fiat Industrial and CNH Global NV will be completed by September. Elkann was speaking as a meeting of Exor, the Agnelli family investment company that he chairs and which controls Fiat and it sister company Fiat Industrial. "Marchionne has spoken about 2015 as the date of his exit (from Fiat) because he thinks many things will have been completed by then," Elkann told the meeting. "But having spoken to him, I'm convinced that he will stay with us for many more years". He added that Marchionne had Exor's full backing for his plan to merge Fiat with Chrysler, which the Italian carmaker took control after bankruptcy in 2009. He also said truck-and-agricultural-vehicles-producer Fiat Industrial's merger with tractor unit CNH Global NV will not take long. "There are a series of procedures (to carry out)," said Elkann, an Agnelli family heir who is a board member of Fiat Industrial as well as being the number one at Fiat. "We believe that between July 4, (American) Independence Day, and September 1, this new entity should come to life. There are no problems on the horizon".