Robert Soros, deputy chairman of Soros Fund Management, will take over management of the $8.4 billion Quantum Endowment Fund, the firm's flagship hedge fund, said industry sources with knowledge of the company. Mr. Soros is son of company founder and chairman George Soros. Michael Vachon, spokesman for Soros Fund Management, declined to comment. The younger Mr. Soros assumes management of the fund from Jacob Goldfield, who reportedly left to start his own money management firm. Mr. Goldfield could not be reached to comment on his future plans.