Brian Cohn, who joined SAC Capital Advisors when it managed just $300 million, has announced his departure from the now-$15 billion firm after 11 years.

Cohn, SAC’s president, told colleagues on Friday that he plans to take a break before pursuing another opportunity. Last summer, Cohen suffered a personal tragedy when his six-year-old son drowned in the family pool.

Before joining Stamford, Conn.-based SAC, Cohn worked at International Fund Services.

Cohn is the second SAC executive to announce he is leaving the firm in a week.

James Rowen, chief financial officer, said last week that he would join East Setauket, N.Y.-based Renaissance Technologies as chief operating officer. SAC said that accounting and operations chief Dan Berkowitz will succeed Rowen, who joins James Simons’ quantitative shop in about a month.