Kenneth Bohlin, the chief executive officer of Informa's financial information (IFI) arm, has decided to retire at the end of the year.The FTSE 250-listed group said that when Bohlin leaves, his reponsibilities will be transferred to Patrick Martell, who was recently appointed chief executive of Informa's business intelligence division.Bohlin has been with the company since 1984 and served as IFI's chief since its launch in 1987.Group chief executive Stephen Carter said Bohlin had built "a robust financial information business with strong market positions", and helped it to expand the company's presence in North America and further afield". For his part, Bohlin said he "could not be more satisfied and content than I am as I leave Informa and enter retirement".