London Stock Exchange Group said Thursday that its chief executive, French national Xavier Rolet, would leave the company by the end of 2018 after almost a decade in charge.
"The board is now initiating a process to find a successor and will work closely with Xavier to ensure a smooth transition process as the group continues to execute on its successful growth strategy," a statement said.
It did not give any indication about the reason for Rolet's departure.
Rolet joined LSEG in 2009 and since then, the company's market value has rocketed to nearly £14 billion ($18.5 billion, 15.7 billion euros) from £800 million, the statement said.
Rolet said he was "extremely proud" to have helped "turn LSEG into a truly global financial market infrastructure group".
Under his stewardship, the company bought US asset manager Russell for $2.7 billion to diversify and boost its business in the United States.
It also bought LCH.Clearnet, the British clearing house.
But also on his watch, the LSEG -- which additionally operates Italy's Borsa Italiana -- failed in separate attempts to merge with the Toronto stock exchange and earlier this year with Germany's Deutsche Boerse.
The EU in March blocked a proposed blockbuster tie-up of the London and Frankfurt stock markets owing to competition concerns and fallout from Brexit.
Speaking on Wednesday, Rolet warned that more British firms would move business to EU countries should Britain fail to hammer out a post-Brexit transition deal by the end of the year.
"In the absence of certainty in the next few months, the businesses, the CEOs, the boards the executive committees of many companies that are based here will have to start acting on worst case scenarios," the 57 year-old said in a speech made at Britain's parliament.
© 2017 AFP