FIIG Securities managing director and chief executive Mark Paton has stepped down from his role as he "explores a potential role" at FIIG and MH Carnegie alternate debt joint venture Gieldan Capital.
Jim Stening has been appointed acting managing director effective immediately, pending the appointment of a new chief executive.
A statement by FIIG said the company has engaged an executive search firm to commence the process of appointing a new chief executive.
FIIG chairman Douglas Bates said Mr Paton had played a key role at the company during his four years at the firm.
Mr Stening said he was "looking forward to rejoining the company" while the search for a replacement is undertaken.
"FIIG is in a strong financial position with a growing and highly engaged client base. I look forward to re-joining the company in an executive capacity," Mr Stening said.