Key executives have left, or are leaving, fixed income broker FIIG Securities, a prominent force in the origination and trading of corporate bonds, often for firms with a conventional credit rating.Mark Paton, the current CEO, has "stepped down from the role," after four years FIIG said in a media release yesterday. Jim Stening will step in as acting managing director.John Cummins, the head of markets at FIIG, left the firm earlier this month to joint marketplace lender SocietyOne as chief investment officer.Paton and the FIIG board "are exploring a potential role at Gieldan Capital, the alternate debt joint venture between FIIG & MH Carnegie," FIIG said.Stening founded FIIG in 1998 and was the managing director of the company for 14 years before being replaced by Paton and moving to a non-executive director role.FIIG has more than A$11 billion in corporate bonds and term deposits under advice in its short-term money market, bonds and custody business.