London Stock Exchange C.E.O. Rolet to Step Down Immediately

LONDON — The London Stock Exchange Group said on Wednesday that Xavier Rolet, its chief executive, would step down immediately, amid a public fight with a major investor who claimed Mr. Rolet was being forced out.

Mr. Rolet had originally planned to retire at the end of next year, giving the exchange operator, one of Europe’s biggest, time to find a replacement. But TCI Fund Management, run by Christopher Hohn, claimed that the exchange had forced Mr. Rolet to retire, and waged an aggressive campaign to keep him in place, calling for Donald Brydon to be replaced as chairman of the exchange.

“Since the announcement of my future departure on 19 October, there has been a great deal of unwelcome publicity, which has not been helpful to the company,” Mr. Rolet said in a news release. “At the request of the board, I have agreed to step down as C.E.O. with immediate effect. I will not be returning to the office of C.E.O. or director under any circumstances.”

The stock exchange operator said that David Warren, the company’s chief financial officer, would serve as interim chief executive until a successor was chosen.

Mr. Rolet had originally planned to retire after the completion of the London Stock Exchange’s merger with Deutsche Börse, but that deal was blocked by regulators this year.

Then last month, Mr. Rolet announced that he would step down from the stock exchange at the end of next year and the exchange would begin the process of finding a successor.

Carsten Kengeter, the Deutsche Börse chief executive, has separately announced that he will leave the German stock exchange operator at the end of the year. It came amid an insider trading inquiry over his stock purchases ahead of an announcement that the exchanges were in merger talks.