SAC chief operating officer to leave as hedge fund transforms NEW YORK (Reuters) - A top lieutenant at Steven A. Cohen's SAC Capital Advisors will leave the hedge fund in the new year as the once $15 billion firm converts to a family office, according to a memo sent to employees and seen by Reuters. Sol Kumin, the firm's chief operating officer, will leave SAC in January, the memo from Cohen said. "We are now moving from a firm which manages external capital to a 'family office' that will manage my capital and employee capital only," Cohen wrote in an email Thursday. We will not need the same degree of business development activity or investor relations as before. After taking a hard look at the evolution of his primary areas of responsibility, Sol has decided to resign, effective January 31, 2014. This summer, a federal grand jury indicted SAC after a long-running insider trading investigation. The firm agreed to plead guilty to the criminal charges earlier in November and pay a $1.2 billion fine as part of a settlement. Cohen has not been personally charged with any crime. SAC will no longer manage money for outside investors including pensions, endowments and wealthy individuals, under the terms of its settlement. The firm also paid $616 million as part of a deal with the U.S. Securities and Exchange Commission. "I am looking forward to taking a break, to recharging my batteries and to figuring out what the next chapter of my life will look like," Kumin said in a statement. Kumin said he will return to Boston, where he grew up, in June next year. News of Kumin's resignation was first reported by the Wall Street Journal. SAC, which once employed more than 900 people in offices on three continents, told employees in October it was closing its London office. In addition to recent investment staff cuts and departures, a dozen marketing and sales people have been let go by SAC in recent months. Reporting by Katya Wachtel; Editing by Andrew Hay and Steve Orlofsky