…The LSE said in a statement Thursday that it will start a search for a successor to Rolet, who has been in charge since May 2009. Rolet would have retired this year if all had gone to plan with the merger with Deutsche Boerse AG, but regulators blocked the takeover on antitrust concerns.

“He has a number of good lieutenants, but they would want to scan the market given the likely changes in the exchange world,” said Niki Beattie, founder of consultancy Market Structure Partners in London. “Given he is not going until December next year, I expect that is to give them time to have a good look around.”

Rolet, whose career started in the 1980s as a trader at Goldman Sachs Group Inc., transformed LSE from a business mostly focused on cash equities into a group with strong positions in …