London Stock Exchange Group said today that its chief executive Xavier Rolet will leave the bourse operator by the end of December 2018.
This comes just under a decade after he took the helm at the firm.
LSE said it would start looking for his successor immediately.
Rolet, who joined the group from Lehman Brothers, said last year that he would leave the group if a merger with Deutsche Boerse went through.
However the collapse of the deal in March meant he opted to stay on for longer.
Under the Frenchman's leadership, the exchange has completed a string of deals including buying up the FTSE Group and clearing house LCH.CLearnet.
But his attempts to make truly transformative deals eluded him.
LSE walked away from an attempted takeover of the Toronto stock exchange in 2011 in the face of a rival bid from Canadian banks, while competition regulators thwarted his bid to merge with Deutsche Boerse.
Rolet took over at LSE from Clara Furse in May 2009, with his banking background making him a popular choice among the exchange's largest customers.
Under his leadership the company's market value has risen from less than £1 billion to almost £14 billion, helped by diversifying into the derivatives, data and index businesses.
LSE said in a separate statement today that group income for the quarter ended September rose 17% to £1.66 billion, with revenue up 14% to £486m as its clearing and FTSE Russell businesses grew strongly.
Analysts had forecast total income of £477.5m.