Andrew Waterworth is a managing director in FTI Consulting's strategic comms division and heads the agency's financial services marketing comms practice.
Waterworth's future destination is unknown, but it is understood that he is quitting the consultancy and embarking on a period of gardening leave before starting a new role towards the end of the year.
Andrew Walton, senior MD and global head of financial services, confirmed Waterworth's departure. Waterworth himself declined to comment.
During his time at the agency he advised clients such as Aviva, BlackRock and Barclays Global Investors.
His departure follows that of London-based global president Geoffrey Pelham-Lane, who left the agency last month.
A trio of MDs, Charlie Armitstead, Greg Quine and Ben Foster, also left last year to form Pendomer after its rebranding under parent FTI.
Meanwhile, British designer fashion brand Hobbs has appointed FTI Consulting as its retained financial and corporate PR adviser, following a competitive pitch process.