Michael Bloomberg to Return to Lead Company He Founded

Michael R. Bloomberg has decided to reassume the leadership of his business empire only eight months after ending his final term as mayor of New York.

Bloomberg told close confidants and senior executives of Bloomberg L.P., a financial data and media company, that Daniel L. Doctoroff, its chief executive and a longtime friend and lieutenant, would leave the company at the end of the year and that he would take over. For years, Bloomberg had insisted that he had no intention of returning full time to the company he founded.