Mark Bourke, group chief executive of IFG Group, is to leave the firm in April to take up an external role.
He has been head of the group, which includes self-invested personal pension provider James Hay, for 13 years.
An announcement to the stock exchange said the company has started recruiting a replacement.
Bourke will remain in his role until the end of April to ease the transition period, the announcement said.
IFG has made a number of significant key appointments in recent months, in particular John Cotter, group finance director, and, David Edwards, chief risk officer.
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